Note: Descriptions are shown in the official language in which they were submitted.
~189178
PUNCH
The present invention relates to an improvement in a
punch.
An example of a conventional punch will now be described
with reference to Figs. 20 and 21. In Fig. 21, a head member
1 is fixed to a base 2. A guide member 3 is fitted in the
head member 1 and fixed thereto by bolts 4. A proximal end
of a support member 5 is rotatably mounted inside the guide
member 3 by a pin 6. A proximal end of an arm 8 is rotatably
mounted at the other end of the support member 5 by a pin 7.
A guide projection 301 is provided on the guide member 3. A
guide gap 9 is formed between the guide projection 301 and a
front face 101 of the head member 1. A guide groove 11 of a
slider 10 is engaged with the guide projection 301. A guide
flange 12 is engaged with the guide gap 9 so that the slider
10 may be movable in the vertical direction .
The slider 10 is connected to the arm 8 by a pin 13.
The arm 8 is rotated about a pin 7 in directions indicated by
a double-headedarrow. As a result, the slider 10 is moved up
and down in the vertical direction. A cylindrical blade 14 is
detachably provided to a lower end of the slider 10. A pad 16
is provided on a paper laying surface 15 on which the tip end
of the cylindrical blade 14 is to abut. As shown in Fig. 20,
the mounting operation of the cylindrical blade 14 is
2~89178
attained by fixing the cylindrical blade 14 to the slider 10 by
inserting a head portion of the cylindrical blade 14 into an insertion
hole 19 without any displacement, screwing a stop screw 17 and press-
fitting the tip end of the stop screw 17 to a concave groove 18. Also,
the substantially same technology is also disclosed in Japanese
Utility Model Publication No. Sho 59-39040.
The above-described conventional punch suffers from the
following defects since the fixture of the cylindrical blade depends
upon the holding manner of the fitting between the insertion hole and
the head portion of the cylindrical blade and the guide portion of the
slider by inserting the head portion of the cylindrical blade into the
insertion hole without any displacement so that the cylindrical blade
is not displaced when the paper is punched. When the cutting
performance of the cylindrical blade is degraded or it is desired to
change a size of the hole to be formed through the paper, it is
necessary to exchange cylindrical blades. Upon the exchange of the
blades, it is necessary to remove the stop screw away and subsequently
draw the cylindrical blade from the insertion hole, then to newly
insert a cylindrical blade into the insertion hole and thereafter to
fix the cylindrical blade by the stop screw. The exchange of the
cylindrical blades is troublesome.
Also, when a new cylindricalbladeisinserted into the insertion
hole, there is no displacement in the engagement between the
cylindrical blade and the insertion hole, and it is impossible to
2189178
carry out the insertion while observing the insertion hole.
Accordingly, it is difficult to insert the head portion of the
cylindrical blade into the insertion hole. Also, in the case where the
large number of the holes should be formed in the paper, the number of
the cylindrical blades is increased. It is therefore troublesome to
replace the cylindrical blades. This point should be improved for use
in office instrument.
Also, since the cylindrical blade is substantially supported by
the slider, this structure has the points to be improved as follows.
In the case where a large stack of paper should be punched, the arm
should be pressed down by a considerably large force. This downward
pressure is directly applied to the slider. Accordingly, if there is
any displacement in the guide portion of the slider, on the way where
the slider is pressed downwardly, the slider would be swung. The swing
motion is transmitted to the cylindrical blade. At the worst, the
cylindricalblade wouldbedamaged.Accordingly, inordertoeliminate
the displacement of the slider, it is necessary to effect a high
precision machining for the guide portion of the slider. The
manufacture cost therefor would be increased disadvantageously.
Also, the displacement of the slider and the curvature of the
cylindrical blade causes the positional displacement at the lowering
position of the tip of the cylindrical blade. It is therefore
difficult to insert the tip of the cylindrical blade into the lower
blade to carry out the cutting operation between the lower blade and
2189178
the tip. It is almost impossible to adopt a system in which the lower
blade is provided. Accordingly, a pad is provided at the lowering
position of the tip, and the tip of the cylindrical blade is pressed
against the pad. Even if the position of the tip is somewhat
displaced, the paper may be well punched. Until the pad is new, the
cutting may be well performed. However, when the pad is subjected to
flaws, even if the tip of the cylindrical blade is not worn but is
sharp, the pads should be replaced. For this reason, the pads should
be replaced frequently and this would be troublesome. This should be
improved for the routine operation of the office instrument.
An object of the present invention is to provide a punch in which
replacement of cylindrical blades is simplified, even if there is a
slight displacement in guide surfaces of a slider, the displacement
does not adversely affect a displacement of a tip end of each
cylindrical blade, and the punching is effected by a lower blade and
the tip end to thereby dispense with a pad.
According to a first aspect of the invention, there is provided
a punch in which a head portion of a blade is detachably held to a
slider that moves up and down in a vertical direction, characterized
in that a holder having a gap for insertion of paper, the gap is U-
shaped in side elevation defined by an upper horizontal portion, a
lower horizontal portion and a vertical portion, through holes are
formed in the upper horizontal portion and the lower horizontal
~189178
portion so that a cylindrical blade traverses the gap, the
holder in which the cylindrical blade has been inserted into
the through holes is inserted and drawn below the slider, and
a head portion of the blade projecting in the upper
horizontal portion is held by the slider.
According to a second aspect of the invention, a
length of the through hole formed in the upper horizontal
portion of the holder is elongated, namely larger than a
length of the diameter of the through hole~ so that the
cylindrical blade is not swung, and a lower blade is formed
in the through hole formed in the lower horizontal portion.
According to a third aspect of the invention, a recess
groove is formed in a circumferential surface of the head
portion of the cylindrical blade, and a convex surface
engaged with the recess groove is formed in a holding
portion of the slider for the cylindrical blade.
According to a fourth aspect of the invention, a
flanged convex portion is formed in a circumferential surface
of the head portion of the cylindrical blade, and a concave
surface engaged with the flanged convex portion is formed in
a holding portion of the slider for the cylindrical blade.
According to a fifth aspect of the invention, a recess
groove is formed in a circumferential portion of the
cylindrical blade, an insertion hole into which a head portion
of the cylindrical blade is provided in a holding portion of
the slider for the cylindrical blade, and a screw hole is
provided so that a tip end of a screw is engaged with the
recess groove of the head portion inserted into the insertion
21 891 7~
hole.
An explanation will be made as to how to solve the
tasks by the above described structure. First of all,
according to the first aspect of the invention, by the
simple steps in which the gap defined by the upper horizontal
portion, the lower horizontal portion and the vertical
portion to form the U-shaped side elevation for insertion of
the paper is traversed by the cylindrical blade, and the
holder having the through holes formed in the upper
horizontal portion and thelower horizontal portion through
which the cylindrical blade traverses is inserted and drawn
below the slider, it is possible to replace the cylindrical
blades. Also, the head portion of the blade projecting into
the upper horizontal portion of the holder is held to the
slider and the up and down movement of the cylindrical blade
is guided by the through hole formed in the upper horizontal
portion of the holder irrespective of the guide portions of
the slider. The swing of the cylindrical blade is obviated
and the lowering position of the blade tip is exactly
determined.
According to the second aspect of the invention, the
length of the through hole formed in the upper horizontal
portion of the holder is elongated, namely larger than a
length of the diameter of the through hole, so that no swing
motion of the cylindrical blade is generated, the guidance
for the up and down movement of the cylindrical blade is more
positive, the swing motion of the cylindrical blade is
eliminated more effectively to keep constant the lowering
position of the blade tip end, the lower blade is provided in
2~9178
the through hole formed in the lower horizontal portion, and the tip
end of the cylindrical blade lowering to an accurate position is
inserted into the lower blade with high precision for cutting and
punching the paper between the lower blade and the tip end of the
cylindrical blade.
According to the third aspect of the invention, since the
prevention of the swing motion of the cylindrical blade does not
depend upon the guide portions of the slider, simply by forming the
recess groove on the circumferential surface of the head portion of
the cylindrical blade, forming the convex surface, that is to be
engaged with the recess groove, in the holding portion of the slider
for the cylindrical blade, and inserting and drawing the holder below
the slider in the engagement between the recess groove and the convex
surface, it is possible to hold the head portion of the cylindrical
blade to the slider.
According to the fourth aspect of the invention, since the
prevention of the swing motion of the cylindrical blade does not
depend upon the guide portions of the slider, simply by forming the
flanged projection on the circumferential surface of the head portion
of the cylindrical blade, forming the concave surface, that is to be
engaged with the flanged projection, in the holding portion of the
slider forthe cylindrical blade, and inserting and drawing the holder
below the slider in the engagement between the recess groove and the
convex surface, it is possible to hold the head portion of the
2189178
cylindrical blade to the slider.
According to the fifth aspect of the invention, the insertion
hole into which the head portion of the cylindrical blade is provided
in the holding portion of the slider for the cylindrical blade, a
screw hole with which the tip end of the screw is engaged is provided
in the recess groove formed in the head portion of the cylindrical
blade which is inserted into the insertion hole, the holder having the
through hole into which the cylindrical blade is inserted is located
below the slider, the head portion of the cylindrical blade is
inserted into the insertion hole by lowering the arm, the tip end of
the screw is fitted in the recess groove of the head portion, and the
head portion of the cylindrical blade is held to the slider.
The embodiment of the invention defined by the first aspect of
the invention is as follows: According to the first aspect of the
invention, in Fig. 1, there is provided a punch in which a head portion
of a blade 14 is detachably held to a slider 10 that moves up and down
in a vertical direction. A holder 28 having a gap for insertion of
paper. The gap is U-shaped in side elevation defined by an upper
horizontal portion 22, a lower horizontal portion 23 and a vertical
portion 24. Through holes 25 and 26 are formed in the upper horizontal
portion 22 and the lower horizontal portion 23 so that a cylindrical
blade 14 traverses the gap. The holder 28 in which the cylindrical
blade 14 has been inserted into the through holes 25 and 26 is inserted
and drawn below the slider 10, and a head portion of the cylindrical
21~17~
blade 14 projecting in the upper horizontal portion 22 of the
holder 28 is held by the slider lO.
The embodiment of the invention defined by the second
aspect of the invention is as follows: In Fig. 4, a length H2
of the through hole 25 formed in the upper horizontal portion
22 of the holder 28 is elongated larger than a length of the
diameter of the through hole, and a lower blade 27 is formed
in the through hole 26 formed in the lower horizontal portion
23.
The embodiment of the invention defined by the third
aspect of the invention is as follows: In Fig. 1, a recess
groove 20 is formed in a circumferential surface of the head
portion of the cylindrical blade 14, and a convex surface 21
engaged with the recess groove 20 is formed in a holding
portion of the slider 10 for the cylindrical blade 14 as
shown in Figs. 10 and 12.
The embodiment of the invention defined by the fourth
aspect of the invention is as follows: A flanged convex
portion is formed in a circumferential surface of the head
portion of the cylindrical blade 14 instead of the recess
groove 20, and a concave surface is formed in a holding
portion of the slider 10 for the cylindrical blade 14 instead
of the convex surface 21. In this case, also, it is possible
to hold the cylindrical blade 14 at the lower end of the
slider 10.
The embodiment of the invention defined by the fifth
aspect of the invention is as follows: In Fig. 2, a recess
groove 20 is formed in a circumferential portion of the
cylindrical blade 14, an insertion
2~89~7~
hole 32 into which a head portion of the cylindrical blade 14 is
provided in a holding portion of the slider 10 for the cylindrical
blade 14 , and a screw hole 33 is provided so that a tip end of a screw
31 is engaged with the recess groove 20 of the head portion inserted
into the insertion hole.
In the accompanying drawings:
Fig.lisasideelevational, longitudinalsectionalview showing
a primary part of a punch provided with a holderin accordance with one
embodiment of the invention;
Fig.2isasideelevational, longitudinal sectionalview showing
a primary part of a punch provided with a slider in accordance with
another embodiment of the invention;
Fig. 3 is a plan view showing the holder shown in Figs. 1 and 2;
Fig. 4 is a longitudinal sectional view taken along the line X-X
of Fig. 3;
Fig. 5 is a frontal view as viewed from the right side of Fig. 4;
Fig. 6 is a bottom view of Fig. 3;
Figs. 7A, 7B and 7C are views showing the order of the steps for
replacing the cylindrical blades of Fig. 1;
Fig. 8 is a view showing an operational condition of the punch
shown in Fig. 1;
Fig. 9 is a plan view showing the slider shown in Figs. 1 and 2;
Fig. 10 is a side elevational view showing the slider shown in
2 1 ~9 1 78
Figs. 1 and 2;
Fig. 11 is a longitudinal sectional view of the slider shown in
Fig. 1, taken along the line Y-Y of Fig. 9;
Fig. 12 is a back view showing the slider shown in Figs. 1 and 2;
Fig. 13 is a frontal view of Fig. 11;
Fig. 14 is a partially fragmentary, plan view of Figs. 1 and 2;
Fig. 15 is a longitudinal sectional view of the slider shown in
Fig. 2, taken along the line Y-Y of Fig. 9;
Fig. 16 is a frontal view of Fig. 15;
Fig. 17 is a plan view showing the guide member shown in Figs. 1
and 2;
Fig. 18 is a side elevational view of Fig. 17;
Fig. 19 ls a perspective view showing the entire punch shown in
Fig. 2;
Fig. 20 is a longitudinal sectional view showing a primary part
of a conventional punch; and
Fig. 21 is a partially fragmentary, longitudinal sectional view
showing the entire state of the conventional punch.
The present invention will now be described by way of example
with reference to the accompanying drawings. An outline of a punch
will now be described with reference to Fig. 19. Each head member 1
mounted on a base 2. An arm 8 is rotatably mounted on a support member
5 (Figs. 1 and 2) incorporated in the head member 1. A holder 28 is
2 ~ ~9 1 78
retractably/projectablyprovided inaU-shapedgapportionOfthehead
member 1. The holder 28 is fixed under the condition that the lower
horizontal portion 23 (Figs. l and 2) is inserted into a recess
portion 151 formed in a paper loading surface 15. In this embodiment,
for example, three punch holes are shown. The number of the punch
holes may be two, four or any other number. Each component will now be
described in order in detail.
The holder 28 will now be described. In Fig. 4, the holder 28 is
U-shaped in side elevation. The holder 28 is composed of an upper
horizontal portion 22, a lower horlzontal portion 23 and a vertical
portion 24. Through holes 25 and 26 are formed in the upper horizontal
portion 22 and the lower horizontal portion 23, respectively, for
insertion of cylindrical blades 14. A diameter of each through hole 25
is selected so that the static engagement is attained without any
displacement between the through hole 25 and the blade 14 to be
inserted into the through hole 25. The vertical movement of the
cylindrical blade 14 may be well guided.
A boss 30 is provided for elongating a length H2 of the through
hole 25. The length H2 is selected so that the vertical movement of the
cylindrical blade 14 is positively carried out and the cylindrical
blade 14 is not vibrated against the cutting resistance of the paper.
Thus, the position of the tip of the cylindrical blade 14 is not
displaced. In this embodiment, the length H2 iS about twice larger
than the diameter of the through hole 25. It is preferable to select
2 1 8~ ~ 78
the lengthH2 at least longer than the diameter ofthe through hole 25.
A lower blade 27 is formed around an edge portion of the through hole
26. The lower blade 27 is fitted with the cylindrical blade 14 with
high precision for cutting the paper.
Fig. 3 is a plan view showing the holder 28. Ribs 29 are provided
in the holder 28. A dimension W1 between the outer walls of the ribs
29 is substantially equal to the inside dimension W2 of the head
member 1, so that the ribs 29 function as a guide member when the ribs
29 engage with the head member 1. As shown in Figs. 3, 4 and 5,
positioning surfaces 241 are provided on the vertical portion 24. The
positioning surfaces 241 are brought into contact with the bottom
portion 102 of the U-shaped cutaway portion of the head member 1, and
an axis of the through hole 25 is coincided with an axis of the
insertion hole 32 (Fig. 2) by the guiding action of the ribs 29. As
shown in Figs. 3 and 5, a guide surface 221 is provided on the upper
horizontal portion 22. When the guide surface 221 is in sliding
contact with the upper horizontal portion 103 of the U-shaped cutaway
portion of the head member 1 to thereby restrict the upward movement
of the holder 28. Thus, the holder 28 is retractably and projectably
positioned relative to the head member 1 by the ribs 29, the
positioning surfaces 241 and the guide surface 221.
Also, as shown in Fig. 4, in the holder 28, the paper insertion
portion having the U-shaped in side elevation and the height H1 is
formed by the upper horizontal portion 22, the lower horizontal
~ ~ 89 1~ 78
portion 23 and the vertical portion 24. The holder28 is reinforced by
the ribs 29 so that the upper horizontal portion 22 and the lower
horizontal portion 23 are integral to have a rigidity. As shown in
Figs. 4 and 6, the through hole 26 is formed in the lower horizontal
portion 23. The lower blade 27 is formed in the edge of the through
hole 26. The lower blade 27 and the tip of the cylindrical blade 14 are
engaged with high precision and the paper is cut between the lower
blade 27 and the tip to form a hole in the paper.
The slider 10 will now be described. Fig. 9 is a plan view of the
slider 10. Guide grooves 11 and guide flanges 12 are provided in the
slider 10. A slit 34 is formed in the central portion of the slider 10
for insertion of the arm 8. A width of the guide flange 12 is greater
than a width W5 between the guide surfaces 36 and stepped portion of
W6 are formed so that a guide member 3 (Figs. 1 and 2) to be described
later may be engaged. A width W7 between the support member guide
surfaces 37 is smaller than a width W5 of guide surfaces 36 so that the
support member 3 do not interfere with the guide surfaces 36 by the
stepped portions W8.
As shown in Fig. 10, a pin hole 35 through which the pin 13 shown
in Figs. 1 and 2 are inserted is formed so as to pass between the guide
surfaces 36. Also, cut chip guide portion 38 is provided in the slider
10. Namely, as shown in Figs. 11 and 12, the chips cut from the paper
by the cylindrical blade 14 (Figs. 1 and 2) are caused to pass through
the interior of the cylindrical blade 14 and discharged from the cut
2189178
chip discharge hole 40 as indicated by the arrows to be discharged
along the cut chip guide surface 39. When the chips are discharged,
the chips are guided by the cut chip guide portion 38 so that the chips
are dispersed to the outside.
Also, in the embodiment shown, as shown in Figs. 11 and 13, a
convex surface 21 is provided in the holding portion of the
cylindrical blade 14 to project toward the surface of the U-shaped
portion opened at its front face, so that the recess groove 20 formed
at the head portion of the cylindrical blade 14 shown in Fig. 1 is
fitted with the convex surface 21. Also, the convex surface 21 may be
concave, and the recess portion 20 formed at the head portion of the
cylindrical blade 14 may be convex so that the concave portion and the
convex portion may be engaged with each other. Figs. 15 and 16 show
another embodiment of the invention. An insertion hole 32 is formed in
the holding portion of the cylindrical blade 14. A diameter of the
insertion hole 32 is greaterthan a diameter of the head portion of the
cylindrical blade 14. In this case, a slight of displacement between
the insertion hole 32 and the head portion to be inserted into the
insertion hole 32 may be allowed. A screw hole 33 is provided to pass
through the insertion hole 32. The other structure is the same as that
shown in Figs. 9 to 12. The same reference numerals are used to
indicate the same member. Accordingly, the duplication of explanation
of the common parts will be omitted.
The guide member 3 will now be described. In Fig. 17, the plan
2189178
view of the guide member 3 is U-shaped. Its open portion is provided
with guide projections 301 for engagement with the guide grooves 11
(Fig. 9) of the slider 10. Also, an inside width W9 is set so that the
guide member 3 may be engaged with the portion having the width W5
between the guide surfaces 36 shown in Fig. 9. An outside width W10 is
set so that the guide member 3 may be engaged with the portion having
the inside width W2 of the head member 1 shown in Fig. 3. As shown in
Fig. 18, bolt holes 41 through which the bolts 4 shown in Figs. 1 and
2 pass and pin holes 43 through which the pin 6 passes for rotatably
supporting the support member 5 are formed on side walls of the guide
member 3. Also, oblong holes 42 are formed so that the pin 7 shown in
Figs. 1 and 2 may be moved.
Fig. 14 shows an assembled state. The guide member 3 is fitted
inside the head member 1. The guide flanges 12 of the slider 10 are
fitted between the guide projections 301 and the front faces 101 of
the head member 1. The guide projections 301 are fitted in the guide
grooves 11. Furthermore, the guide surfaces 36 are in sliding contact
with the inside walls of the guide member 3 so that the slider 10 may
be moved up and down in the vertical direction. Also, the proximal end
of the arm 8 is supported by the support member 5 by the pin 7. Both
ends of the pin 7 are located within the oblong holes 42 formed in the
guide member 3, so that the pin 7 may be moved in accordance with the
rotation of the support member 5.
The operation of the above-described embodiments will now be
16
2 1 89 1 78
described. The operation of the replacement of the cylindrical blades
14 will first be described. Under the condition that the cylindrical
blade 14 is inserted into the through holes 25 and 26 of the holder 28
as shown in Fig. 7, the holder 28 is moved in the direction indicated
by the arrow A and located below the slider 10 so that the head portion
of the cylindrical blade 14 which is projected from the holder 28 may
be held by the slider 10.
In holding the head portion of the cylindrical blade 14 to the
above-described slider 10, the recess groove 20 is formed in the head
portion of the cylindrical blade 14 is provided as shown in Fig. 1, and
the convex surface 21 which engages with the recess groove 20 is
formed in the holding portion of the slider 10 as shown in Figs. 11 and
13. As a result, the holder 28 is simply moved in the direction
indicated by the arrow A as shown in Fig. 7A while lowering arm 8 to
lower the slider 10 and engaging the convex surface 21 with the recess
groove 20, so that the head portion of the cylindrical blade 14 may be
held to the slider 10.
Also, the portion corresponding to the above-described recess
groove 20 may be formed into a flanged portion having the convex
surface, and the portion corresponding to the above-described concave
portion 21 may be formed into a portion having the convex surface.
Only by moving the holder 28 in the direction indicated by the arrow
A while engaging the convex and concave portion with each other as
shown in Fig. 7A, it is possible to hold the head portion of the
~t~39178
cylindrical blade 14 to the slider 10 in the same way.
Also, the insertion hole 32 is provided in the holding portion of
the cylindrical blade 14 of the slider 10 as shown in Fig 15. The arm
8 is raised to raise the slider 10 so that the cylindrical blade 14 is
inserted into the through holes 25 and 26 of the holder 28. Under this
condition, the holder 28 is moved in the direction indicated by the
arrow A in Fig. 7A so that the holder 28 is located below the slider
10. Thereafter, the arm 8 is lowered to lower the slider lO so that the
head portion of the cylindrical blade 14 which is projected from the
holder 28 may be fitted in the insertion hole 32. Then, the screw 31
is threadedly engaged with the screw hole 33 so that the tip end of the
screw 31 is engaged with the recess groove 20 formed in the head
portion of the cylindrical blade 14. As a result, it is possible to
hold the head portion of the cylindrical blade 14 to the slider 10.
In inserting the head portion into the insertion hole 32, by
moving the holder 28 in the direction indicated by the arrow A in Fig.
7A while pressingly lowering the arm 8 with a small power and bringing
the head portion of the cylindrical blade 14 projecting from the
holder 28 in sliding engagement with the lower surface of the slider
10, it is possible to readily insert the head portion of the
cylindrical blade 14 into the insertion hole 32 without observing the
operation. Also, the ribs 29 are formed in the holder 28 and the
positioning surfaces 241 are formed on the vertical portions 24. The
holder 28 is inserted until the positioning surfaces 241 are brought
2~89178
into contact with the bottom portion 102 of the U-shaped cutaway
portion of the head member 1 under the guidance of the ribs 29. As a
result, it is possible to coincide the axis of the cylindrical blade
14, which is inserted into the through holes 25 and 26 of the holder
28, with the axis of the insertion hole 32. Under this condition
without any additional operation, itis possible to readily insert the
head portion of the cylindrical blade 14 into the insertion hole 32
without observing the insertion hole 32.
The order of replacement of the cylindrical blades 14 will now be
described. First of all, the recess groove 20 formed in the head
portion of the cylindrical blade 14 is fitted with the convex surface
21 formed in the slider 10. The case where the cylindrical blade 14 is
held to the slider 10 will be explained. In Fig. 7A, the paper loading
surface 15 is moved in the direction indicated by the arrow B. The
fixing of the holder 28 by the recess portion 151 (see Fig. 19) is
released. The holder 28 is drawn in the opposite direction to the
direction A. Next, a new cylindrical blade 14 is inserted into the
through holes 25 and 26 of the holder 28. The arm 8 is lowered to the
lowermost position. As a result, the heights of the recess groove 20
and the convex surface 21 are identified with each other. The holder
28 is moved in the direction A. As shown in Fig. 7B, the recess groove
20 and the convex surface 21 are fitted with each other. The holder 28
is located in the position below the slider, and the cylindrical blade
14 is held to the slider 10. Next, the paper loading surface 15 is
~18ql78
moved in a direction indicted by the arrow C so that the holder 28 is
fixed by the recess portion 151 as shown in Fig. 7C.
In the embodiment shown in Fig. 2, in the case where the head
portion of the cylindrical blade 14 is inserted into the insertion
hole 32 and the tip end of the screw 31 is fitted in the recess groove
20 so that the cylindrical blade 14 is held to the slider 10, the
replacement order of the cylindrical blades 14 will now be described.
First of all, the screw 31 is loosened until the tip end of the screw
31 is disengaged from the recess groove 20. Next, the arm 8 is raised
up to a position where the lower end of the slider 10 does not
interfere with the head portion of the cylindrical blade 14. As a
result, since the engagement between the insertion hole 32 and the
head portion of the cylindrical blade 14 includes the displacement,
the cylindrical blade 14 is not raised by the slider 10. Only the
slider 10 is raised under the condition that the cylindrical blade 14
is left in the holder 28.
Subsequently, as shown in Fig. 7A, the paper loading surface 15
is moved in the direction B, and the fixing of the holder 28 by the
recess portion 151 is released. The holder 28 is drawn in the
direction opposite the direction A. When the holder 28 is drawn, since
it is possible to increase a gap to any desired length between the
lower end of the slider 10 and the head portion of the cylindrical
blade 14, the cut chips do not clog the gap and the holder 28 may be
smoothly drawn. Next, a new cylindrical blade 14 is inserted into the
2 1 891 78
through holes 25 and 26 of the holder 28. The holder 28 is inserted
into the direction A in Fig. 7A. The head portion of the cylindrical
blade 14 is inserted into the insertion hole 32. The tip end of the
screw 31 is engaged with the recess groove 20. Next, the paper loading
surface 15 is moved in the direction C as shown in Fig. 7B. The holder
28 is fixed by the recess portion 151 as shown in Fig. 7C.
The guidance of the cylindrical blade 14 by the holder 28 will
now be described. In Fig. 8, the arm 8 is moved up and down among the
positions 8A, 8B and 8C. The slider 10 is moved up and down in the
vertical direction among the position lOA, lOB and lOC under the
guidance by the guide flanges 12, the guide grooves 11 and the guide
surfaces 36. By the up and down movement of the slider 10, the
cylindrical blade 14 held at the lower end portion of the slider 10 is
also moved up and down among the positions 14A, 14B and 14C. Then, the
up-and-down movement of the cylindrical blade 14 is guided by the
through hole 25 of the holder 28. Accordingly, even if there is a
slight displacement in the guide portions of the guide flanges 12, the
guide grooves 11 and the guide surfaces 36 between the recess groove
20 and the convex surface 21, the cylindrical blade 14 is guided by the
through hole 25 and moved up and down in the vertical direction. Also,
by increasing the height H2 of the through hole 25 (Fig. 4), it is
possible to more positively restrict the escape of the tip end of the
cylindrical blade 14 upon the punching operation. With respect to the
guidance of the cylindrical blade 14 by the through hole 25, it is
218ql78
possible to enjoy the same effect in the case where the head portion
of the cylindrical blade 14 is inserted into the insertion hole 32 as
shown in Fig. 2.
Thus, even if there is a slight displacement in the engagement
between the recess groove 20 and the convex surface 21 (engagement
between the insertion hole 32 and the head portion of the cylindrical
blade 14) and in the guide portions of the guide flanges 12, the guide
grooves 11 and the guide surfaces 36, the cylindrical blade 14 is
guided by the through holes 25. Since there is no up and down
displacement of the tip end of the cylindrical blade 14, it is
possible to form the lower blade 27 in the lower horizontal portion 23
of the holder 28 as shown in Fig. 4 and to carry out the high precision
engagement of the tip end of the cylindrical blade 14 and the lower
blade 27 for cutting and punching the paper.
As described above in detail, according to a first aspect of the
invention that has been understood from the detailed description
thereof, by the simple steps in which the gap defined by the upper
horizontal portion, the lower horizontal portion and the vertical
portion to form the U-shaped side elevation for insertion of the paper
is traversed by the cylindrical blade, and the holder having the
through holes formed in the upper horizontal portion and the lower
horizontal portion through which the cylindrical blade traverses lS
inserted and drawn below the slider, it is possible to replace the
cylindrical blades. Accordingly, the replacement of the cylindrical
2189178
blades may be facilitated. It is therefore possible to
enhance the handling property as the office instrument.
Also, the head portion of the blade projecting into
the upper horizontal portion of the holder is held to the
slider and the up-and- down movement of the cylindrical blade
is guided by the through hole formed in the upper horizontal
portion of the holder irrespective ofthe guide portions of
the slider. Accordingly, the high precision machining work of
the guide portions of the slider is dispensed with to reduce
the manufacture cost. Then, the swing of the cylindrical
blade is obviated and the lowering position of the blade tip
is exactly determined. It is possible to cut the paper
between the tip end of the cylindrical blade and the lower
blade and to dispense with the pad. The handling property is
enhanced as the office instrument by dispensing with the pad
replacement. Also, it is possible to keep a long service life
of the blades. It is possible to enhance the function as the
office instrument.
According to a second aspect of the invention which is
understood from the detailed description thereof, the length
of the through hole formed in the upper horizontal portion of
the holder is elongated larger than a length of the diameter
of the through hole, the guidance for the up-and-down movement
of the cylindrical blade is more positive, the swing motion
of the cylindrical blade is eliminated more effectively to
keep constant the lowering position of the blade tip end, the
lower blade is provided in the through hole formed in the
218~178
lower horizontal portion, and the tip end of the cylindrical blade
lowering to an accurate position is inserted into the lower blade with
high precision for cutting and punchlng the paper between the lower
blade and the tip end of the cylindrical blade. Accordingly, it is
possible to dispense with the pad, to enhance the handing property as
the office instrument and to keep a long service life of the blades to
enhance the function as the office instrument.
According to a third aspect of the invention which is understood
from the detailed description thereof, since the prevention of the
swing motion of the cylindrical blade does not depend upon the guide
portions of the slider, simply by forming the recess groove on the
circumferential surface of the head portion of the cylindrical blade,
forming the convex surface, that is to be engaged with the recess
groove, in the holding portion of the slider for the cylindrical
blade, and inserting and drawing the holder below the slider in the
engagement between the recess groove and the convex surface, it is
possible to hold the head portion of the cylindrical blade to the
slider. Accordingly, the replacement of the cylindrical blades is
extremely simplified to enhance the handing property as the office
instrument.
According to a fourth aspectofthe inventionwhich isunderstood
from the detailed description thereof, since the prevention of the
swing motion of the cylindrical blade does not depend upon the guide
portions of the slider, simply by forming the flanged projection on
24
~789178
the circumferential surface of the head portion of the cylindrical
blade, forming the concave surface, that is to be engaged with the
flanged projection, in the holding portion of the slider for the
cylindrical blade, and inserting and drawing the holder below the
slider in the engagement between the recess groove and the convex
surface, it is possible to hold the head portion of the cylindrical
blade to the slider. Accordingly, the replacement of the cylindrical
blades is extremely simplified to enhance the handing property as the
office instrument.
According to a fifth aspect of the invention which is understood
from the detailed description thereof, the insertion hole into which
the head portion of the cylindrical blade is provided in the holding
portion of the slider for the cylindrical blade, a screw hole with
which the tip end of the screw is engaged is provided in the recess
groove formed in the head portion of the cylindrical blade which is
inserted into the insertion hole, the holder having the through hole
into which the cylindrical blade is inserted is located below the
slider, the head portion ofthe cylindrical blade is inserted into the
insertion hole by lowering the arm, the tip end of the screw is fitted
in the recess groove of the head portion, and the head portion of the
cylindrical blade is held to the slider. It is possible to insert the
head portion of the cylindrical blade into the insertion hole without
observing the insertion hole, to thereby extremely simplify the
replacement of the cylindrical blades to enhance the function as the
office instrument. 2 1 891 78
26
