U.S. patent number 3,719,117 [Application Number 05/167,326] was granted by the patent office on 1973-03-06 for punch holder.
Invention is credited to Robert W. Mauk, William B. Scott.
United States Patent |
3,719,117 |
Mauk , et al. |
March 6, 1973 |
PUNCH HOLDER
Abstract
A punch press includes a tubular punch holder telescoped on the
lower end of a reciprocable ram for up and down movement between
(a) a clamped position in which the end of the ram holds a punch
locked within the holder and (b) a released position in which the
end of the ram is retracted upwardly relative to the holder to
allow the punch to be removed from the holder. Formed in the side
of the holder is an entryway correlated in size and shape to that
of the punch so that the punch may be inserted into and removed
from the holder by being moved radially in and out of the holder
when the latter is in the released position.
Inventors: |
Mauk; Robert W. (Rockford,
IL), Scott; William B. (Rockford, IL) |
Family
ID: |
22606904 |
Appl.
No.: |
05/167,326 |
Filed: |
July 29, 1971 |
Current U.S.
Class: |
83/698.91;
279/126; 403/331; 279/156 |
Current CPC
Class: |
B21D
28/34 (20130101); Y10T 279/3487 (20150115); Y10T
403/61 (20150115); Y10T 83/9476 (20150401); Y10T
279/21 (20150115) |
Current International
Class: |
B21D
28/34 (20060101); B26d 001/06 () |
Field of
Search: |
;83/698,527 ;287/104,13R
;279/9R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Juhasz; Andrew R.
Assistant Examiner: Bray; W. Donald
Claims
We claim as our invention:
1. A punching machine for reciprocating an upright punch unit
having an elongated shank with an enlarged head at the upper end
thereof, said machine comprising a ram adapted for up and down
reciprocation, a tubular punch holder having an axial passage
therethrough and telescoped over said ram with the lower end of the
ram projecting into said passage, an elongated slot formed through
one side of said holder, an enlarged opening formed through said
holder at the upper end of said slot, the size and shape of said
slot and opening being correlated with the size and shape of said
shank and head, respectively, to permit movement of said punch unit
radially into said punch holder, mating seats on said punch unit
and the inner side of said punch holder and engageable with one
another to limit axial movement of the punch unit downwardly within
said holder, and means mounting said punch holder on the lower end
of the ram for reciprocation with the ram and also for selective
axial movement relative to the ram between (a) a clamped position
in which the end of said ram closes off at least the upper end
portion of said opening, engages the head of said punch unit and
forces said seats into engagement to lock said punch unit in said
holder, and (b) a released position in which the end of the ram
releases said head and opens up said upper end portion of said
opening to permit radial movement of said punch unit out of said
holder.
2. A punching machine as defined by claim 1 including an operator
for moving said holder axially relative to the ram between said
clamped and released positions.
3. A punching machine as defined by claim 2 wherein said operator
is power actuated.
4. A punching machine as defined by claim 2 wherein said mounting
means includes a carrier connected between the ram and the holder
and being movable axially relative to the end of the ram by said
operator to carry said holder between said clamped and released
positions.
5. A punching machine as defined by claim 4 wherein said holder
includes an outer flange at a periphery of the upper end of the
holder, said carrier being a collar with a generally horizontal
annular lip on the lower end of the collar positioned to engage the
lower surface of the flange and limit movement of said holder
downwardly within the collar, a threaded upper end portion on the
collar and holding the collar on the ram so that the collar may be
turned to move axially relative to the lower end of the ram, and
gear teeth on said upper end portion for engagement with said
operator to be turned thereby to move said holder between said
clamped and released positions.
6. A punching machine as defined by claim 4 in which said operator
is power actuated and further including of means for automatically
deactivating the operator once said holder is moved into said
positions.
7. A punching machine as defined by claim 6 wherein said
last-mentioned means includes a switch housing mounted on said ram
above said carrier, first and second limit switches mounted within
said housing, and first and second cams mounted within said housing
and movable vertically with said carrier, said first cam actuating
the first limit switch to deactivate said operator when said
carrier moves the holder into said clamped position, and said
second cam actuating the second limit switch to deactivate said
operator when the carrier moves the holder into said release
position.
8. A punching machine as defined by claim 1 further including means
for holding said punch holder angular movement relative to the end
of the ram and for holding said punch unit against angular movement
relative to said holder.
9. A punching machine as defined by claim 8 wherein said holding
means includes a key fastened to the side of the ram, and a
longitudinal keyway formed in the inner wall of said punch holder
to receive said key and prevent the holder from moving angularly
relative to the end of the ram.
10. A punching machine as defined by claim 9 wherein the enlarged
head of said punch unit includes a notch to hold said key extending
past the end of the ram to fit within said notch to hold said unit
against angular movement relative to said holder and the end of the
ram.
11. A punching machine as defined by claim 1 wherein said punch
unit includes a punch with an elongated body having an enlarged
upper end portion, said body being substantially smaller than the
slot and opening in the side of the holder, the diameter of said
enlarged upper end portion being smaller than the smallest diameter
of said axial passage, said punch unit further including an adapter
sleeve with an entryway formed through one side thereof, said
entryway conforming to the size and shape of said punch body to
permit said tool to be moved radially into the adapter sleeve,
holding surfaces on said punch and on the inside of said adapter
sleeve and engageable with one another to limit axial movement of
the punch downwardly within the sleeve, and a spacer mounted on top
of the enlarged upper end portion of the punch with the top surface
of the spacer substantially flush with the top edge of the
sleeve.
12. A punching machine as defined by claim 11 including means for
preventing relative angular movement of said punch holder, said
adapter sleeve and said punch with respect to each other and with
respect to said ram when mounted together on the end of the
ram.
13. A punching machine as defined by claim 12 wherein said holding
means includes a first key fastened to the side of the ram, a
longitudinal keyway formed in the inner wall of said punch holder
to receive said first key and hold the holder angularly oriented on
the end of the ram, a first notch formed in the outside wall of
said adapter sleeve, said key extending past the end of the ram to
fit within said first notch to hold said adapter sleeve against
angular movement relative to said holder and the end of the ram, a
second key fastened to the inside wall of said adapter sleeve, a
second notch formed in the enlarged upper end of the said punch,
and said second key extending into said second notch to hold said
punch against angular movement within said adapter sleeve.
14. For holding a tool having an elongated shank with an enlarged
head at one end thereof, the combination of, an outer sleeve member
formed with an axially extending passage, and elongated slot formed
through one side of said sleeve, an enlarged opening formed through
said sleeve at one end of said slot, said slot and said opening
being sized and shaped to permit radial movement of said shank and
said head, respectively, into said passage when said tool is moved
radially toward said sleeve, coacting surfaces on said tool and the
inner side of said sleeve and engageable with one another to limit
axial movement of the tool in one direction within the sleeve, and
an inner member telescoped into said sleeve member, one of said
members being movable axially relative to the other member between
(a) a clamped position in which one end of said inner member closes
off at least a portion of said opening, engages the head of said
tool and forces said surfaces into engagement to lock said tool in
said sleeve, and (b) a released position in which said one end of
said inner member releases said head and opens up said one portion
of said opening to permit radial movement of said tool out of said
sleeve.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a punch holder of the type which
is used to clamp and unclamp a punch on the end of the reciprocable
ram of a punch press. More particularly, the invention relates to
the type of holder with an axial passage narrowed by an annular
mating surface or seat upon which the punch is supported by a
complementary surface on the punch head to limit downward movement
of the punch within the holder.
SUMMARY OF THE INVENTION
The primary object of this invention is to provide a novel punch
holder of the above general character which, while still serving to
rigidly anchor the punch in a precise radial, axial and angular
position, is effective to simplify the tool changing operation and
thereby substantially reduce the time and work previously required
by a punch press operator to change punches.
A related object is to provide a punch holder which is movable
automatically between clamped and released positions to clamp and
unclamp the punch on the end of the ram, the holder uniquely
retaining the unclamped punch on the ram to prevent the punch from
falling out of the holder and interfering with the advance of a
workpiece preparatory to the next punching operation and thus
freeing the punch press operator for the performance of other tasks
while the holder moves between the clamped and released
positions.
A more detailed object is to provide a holder whose side is formed
with a unique radial entryway which is closed when the punch is
clamped in the holder and which is open when the punch is unclamped
so that the punch press operator need only to move the unclamped
punch radially out of the holder and loosely hang another in the
holder to perform his part in changing punches.
A further object is to provide a holder which is power actuated
between the clamped and released positions and which is stopped
automatically upon reaching either of those positions.
Invention also resides in the provision of a novel adapter which
enables use of the punch holder with punches of various sizes.
These and other objects and advantages of the present invention
will become more apparent from the following detailed description
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary elevational view of a ram equipped with a
new and improved punch holder embodying the novel features of the
present invention.
FIG. 2 is a fragmentary cross-sectional view taken substantially
along line 2--2 of FIG. 1.
FIG. 3 is a cross-sectional view taken substantially along line
3--3 of FIG. 1.
FIG. 4 is a fragmentary cross-sectional view similar to FIG. 2 but
showing parts in moved positions.
FIG. 5 is a fragmentary side elevational view taken substantially
along line 5--5 of FIG. 1.
FIGS. 6 and 7 are cross-sectional views taken substantially along
lines 6--6 and 7--7 respectively, of FIG. 5.
FIG. 8 is a front elevational view showing an adapter used for
mounting a smaller punch in the punch holder.
FIG. 9 is a cross-sectional view taken substantially along line
9--9 of FIG. 8.
FIG. 10 is a view taken substantially along line 10--10 of FIG.
8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in the drawings for purposes of illustration, the present
invention is embodied in a tubular punch holder 20 used to secure a
punch unit 21 on the reciprocating ram 23 of a punch press for
performance of a punching operation on a workpiece (not shown) when
the ram is moved through advance and return strokes by a fluid
operated actuator. Herein, the holder is telescoped onto the lower
end of the ram and includes an axial passage 24 (FIG. 2) which is
narrowed at its lower end by a downwardly tapered annular seat 25.
A complementary mating seat 26 is formed on the punch 21 which, in
the present instance, includes an elongated shank 27 and an
enlarged head 29. The latter is located on the upper end of the
punch and includes a frusto-conical lower surface which forms the
complementary mating seat 26. When the punch is inserted into the
holder, the two mating seats 25 and 26 engage each other as shown
in FIG. 2 to center the punch radially in the holder and to limit
downward axial movement of the punch within the holder thereby to
keep the punch from being pulled downwardly out of the holder on
the return stroke of the ram.
Upward vertical restraint for the punch 21 is provided as a result
of the lower end of the ram 23 engaging the top surface of the head
29 in a clamped position (see FIG. 1) to securely seat the punch
within the holder 20. Moreover, angular movement of the punch
holder and the punch relative to each other and to the ram is
prevented by an elongated key 30 (FIG. 2) fastened in a slot 31 in
the side of the ram by a pin 33. The key extends radially outward
from the side of the ram and slidably fits within a vertical keyway
34 grooved in the inner wall of the holder thus limiting relative
angular movement of the holder and ram. The lower end of the key
extends downwardly past the lower end of the ram and fits within a
notch 35 (FIG. 3) which is cut in the side of the enlarged head of
the punch unit so as to hold the punch in a particular angular
orientation relative to both the ram and the holder. Thus, the
punch is located in a precisely centered position on the end of the
ram by the mating seats 25 and 26 and is located in a precise
angular position by the key 30.
Frequently, the punch 21 is removed from the punch holder 20 and is
replaced with a punch of a different size or shape. In accordance
with the primary aspect of the present invention, the punch
changing operation is greatly simplified through the provision of a
novel punch holder 20 which avoids the need for the operator of the
punch press to manually hold the punch 21 while the latter is being
clamped to and unclamped from the holder. For this purpose, a novel
entryway 36 is formed through one side of the holder to permit
radial loading and unloading of the punch 21 into and out of the
axial passage 24. After the punch has been loaded manually into the
holder through the radial entryway 36, and hung loosely in the
axial passage, the holder is automatically moved upwardly on the
ram 23 to a clamped position (FIG. 1) in which the lower end of the
ram closes off the entryway and clamps the punch securely in the
holder. While the punch is being clamped, the press operator need
not hold the punch in place and is free to perform other tasks
since the punch holder itself retains the punch during such
clamping. When the punch is to be removed, the holder is
automatically moved downwardly on the ram to a released position
(FIG. 4) in which the lower end of the ram unclamps the punch and
opens up the radial entryway 36 for subsequent manual unloading of
the punch. As the punch is being unclamped, the operator need not
hold the punch since, once unclamped, the punch simply hangs
loosely in the axial passage 24 and cannot fall downwardly out of
the holder and onto the workpiece. Accordingly, the punch holder of
the present invention requires less time and attention on the part
of the press operator during a punch changing cycle.
In the present instance, the entryway 36 includes an elongated slot
37 (FIG. 1) formed through the side of the holder diametrically
opposite the keyway 34. Centered at the upper end of the slot is an
enlarged generally rectangular opening 39 also formed entirely
through the side of the holder to lead into the axial passage 24.
The size and shape of the slot and opening conform generally to the
cross-sectional size and shape of the shank 27 and the enlarged
head 29, respectively, of the punch 21. Thus, when the holder is in
its released position shown in FIG. 4 and the lower end of the ram
23 uncovers the entryway, the punch can be moved radially into the
holder and then lowered into the passage with the seat 26 loosely
engaging the seat 25 to prevent the punch from dropping out of the
lower end of the passage.
When placing the punch 21 within the holder 20, the notch 35 on the
periphery of the punch head 29 is aligned angularly with the key 30
extending along the side of the ram 23 opposite the entryway 36.
The punch cannot be inserted completely into the holder without the
notch interfitting with the key and, if the punch press operator
finds that the notch and key are misaligned, a simple twist one way
or the other will properly align the punch within the holder and
allow the punch to be radially pushed into axial alignment with the
ram.
It is possible to mount the holder 20 for relative axial movement
between its clamped and released positions with respect to the
lower end of the ram 23 in various ways without deviating from the
concept of the present invention. For instance, the holder could be
held in a fixed position on the ram with a separate lower end
portion of the ram being movable up and down within the main
portion of the ram to open and close the entryway 36. For
simplicity in construction, however, the present arrangement
employs a movable carrier in the form of a collar 40 (FIG. 2)
connected at its lower end to the holder and internally threaded
for vertical movement on an intermediate portion of the ram to
carry the holder between the clamped and released positions. The
upper end of the collar is formed with external gear teeth 41
meshing with the teeth of a drive gear 43 connected to be rotated
by a reversible motor 44 which is mounted on the side of the ram by
a support block 45. As the collar is turned, it moves upwardly or
downwardly (depending upon the direction of turning) on an external
thread 46 formed on the side of the ram. The gear teeth 41 spline
with the gear 43 as the collar moves vertically thereby to enable
movement of collar relative to the motor.
Herein, the holder 20 is loosely telescoped into the collar 40, an
outer flange 47 (FIG. 2) at the periphery of the upper end of the
holder resting on an annular lip 49 formed on the inner wall at the
lower end of the collar to limit downward movement of the holder
within the collar. As shown, the holder is telescoped over a
reduced lower end portion 50 of the ram and slides up and down
thereon when moved between the clamped and released positions. When
in the clamped position as shown in FIG. 2, the top surface of the
holder is spaced below the lower surface 51 of the threaded portion
46 of the ram because the length of the reduced portion 50 is
longer than the distance between the top surface of the punch 21
and the top surface of the holder. Thus, when in the clamped
position, the extreme lower end surface of the ram presses against
the top surface of the punch to force the mating surfaces 25 and 26
together to seat the punch tightly in the holder.
In summary, the empty punch holder 20 is initially disposed in a
lowered released position as shown in FIG. 4 in which the extreme
lower end of the ram is located above the enlarged top opening 39
of the entryway 36. To load the punch 21 into the holder, the press
operator simply moves the punch radially into the entryway and
thereafter allows the punch to drop downwardly into the passage 24,
the head 29 of the punch then being located below the enlarged
opening and the punch hanging loosely in the holder by virtue of
the engagement of the seats 25 and 26. The press operator next
energizes the motor 44 to move the holder upwardly to its clamped
position (FIG. 2) and, during such movement, the operator may move
onto another task without danger of the punch falling downwardly
onto the underlying workpiece, which usually is being advanced into
position beneath the punch.
As the punch holder 20 moves upwardly to its clamped position (FIG.
2), the lower end portion 50 of the ram 23 closes off the enlarged
opening 39 of the entryway 36 to preclude any possibility of the
punch 21 escaping radially from the entryway. Thereafter, the head
29 of the punch engages the extreme lower end of the ram to press
the seat 26 into tight clamping engagement with the seat 25 and
thereby lock the punch tightly in the holder in an accurately
centered position.
When the punch 21 is to be removed, the operator merely energizes
the motor 44 in a direction causing the punch holder 20 to move
downwardly to its released position (FIG. 4). During such movement,
the head 29 of the punch moves downwardly away from the extreme
lower end of the ram 23 to release the clamping pressure between
the seats 25 and 26 and, in addition, the enlarged opening 39 moves
downwardly from the lower end portion 50 to open up the entryway 36
for subsequent radial unloading of the punch. The operator need
not, however, unload the punch immediately and indeed not attend to
the punch at all during the unclamping since the seats 25 and 26
retain the punch in the holder until the operator removes the punch
radially through the entryway.
Advantageously, the holder 20 is stopped automatically at the
clamped and released positions. For this purpose, upper and lower
limit switches 53 and 54 (FIG. 5) connected through appropriate
circuitry with the motor 44 are tripped to deactivate the motor by
a cam plate 55 which rides vertically with the collar 40 as it is
moved between the two positions. As shown in FIGS. 1 and 5, the
limit switches and the cam plate are carried on the side of the ram
23 within a rectangular housing 56. The cam plate is slidable
within the housing, extends vertically through the bottom thereof
and is resiliently biased downwardly by upper springs 57 so as to
engage the upper edge of the collar. As the collar moves between
the clamped and released positions, the plate slides past
spring-loaded switch actuators 59 (FIGS. 6 and 7) which ride
against two curved cam surfaces 60 and 61 on the plate to trip the
proper limit switch and deactivate the motor which, in turn, stops
the holder in one of the positions.
More particularly, the upper limit switch 53 is tripped as the
holder 20 reaches the clamped position by the cam surface 61 which
in the present instance is formed by a vertically adjustable block
63 (FIG. 7) fastened by a locking bolt 64 within a widened slot 65
cut in the cam plate 55. Vertical adjustment of the cam block 63
allows for precise stopping of the holder in the clamped position
to avoid binding of the threads 46 by threading the collar 40 too
far up on the ram 23 or to avoid not threading the collar far
enough up on the ram and leaving the end of the ram short of the
punch 21. The lower limit switch 54 serves to deactivate the motor
as the holder reaches the released position and, in this instance,
the curved portion of the cam surface 60 slides downwardly with the
collar to engage the actuator 59 and thereby trip the switch.
Herein, the cam surface 60 is formed by an elongated groove 66 cut
within the cam plate with a curved upper end portion for sliding
past the actuator to trip the lower limit switch 54.
Thus, the collar 40 is stopped at the clamped and released
positions by the cam plate 55 as it rides on top of the collar to
trip the upper and lower limit switches 53 and 54. Should the
collar be removed from the lower end of the ram 23, a keeper pin 67
(FIG. 6) fastened to and extending outwardly from the cam plate
engages the bottom wall of the housing 56 to prevent the cam from
falling out of the housing.
In accordance with another aspect of the present invention, the
holder 20 is adapted for use with a wide variety of shapes and
sizes of smaller punches 69. For this purpose, novel provision is
made of a tubular adapter 70 (FIG. 8) sized to fit within the
holder to reduce the size of the axial passage 24 while still
permitting radial tool changing, and provision also is made of a
spacer 71 for effectively lengthening the punch for axial locking
within the holder. With such adapters and spacers, the holder can
be used in conjunction with a wide variety of differently sized and
shaped punches which may be changed as easily and quickly as the
one piece punch unit 21 and without need of changing the
holder.
In the present instance, the adapter 70 is formed as a tubular
member having an axial opening 73 (FIGS. 9 and 10) and an outer
size and shape substantially equal to the size and shape of the
upper end portion of the one-piece punch 21. The adapter thus is
sized to fit within the axial passage 24 of the holder 20 in the
same fashion as the one-piece punch. When the adapter is fitted
within the holder, a T-shaped slot 74 formed in and extending from
the top to the bottom of one side of the adapter aligns with the
entryway 36 in the holder and extends completely through the side
of the adapter into the axial opening 73. The latter extends
axially through the adapter and includes an enlarged upper end
portion 75 (FIG. 9) sized to receive the head of the small punch 69
and a narrowed lower end portion 76 sized to fit around the shank
of the small punch. A holding surface 77 is formed between the two
end portions and below the enlarged upper end of the T-slot for
engagement with a complementary holding surface 79 on the punch to
prevent the punch from sliding through the axial opening 73 when
dropped into the adapter. Thus, the seating together of the two
holding surfaces and the inside walls of the adapter act to hold
the punch axially and radially within the holders.
To hold the small punch 69 angularly within the holder 20, a
rectangular notch 80 (FIGS. 9 and 10) is cut through the side of
the adapter 70 diametrically opposite the T-slot 74 and extends
downwardly from the top of the adapter to about the mid-portion
thereof. Mounted by a pin 81 (FIG. 9) in the bottom of the notch is
a key 82 engageable within a keyway 83 formed in the periphery of
the head of the smaller punch to hold the punch angularly within
the adapter. The upper outer sides of the notch engage the key 30
on the side of the ram in a manner similar to the engagement of the
key and the notch 35 in the periphery of the normal sized punch
unit 21 to hold the adapter angularly within the holder.
To increase the effective length of the small punch 69 so that the
latter may properly fit within the holder 20, the spacer 71 is
mounted on top of the head of the punch. Herein, the spacer is
formed as a circular metal slug 84 (FIG. 8) having a diameter equal
to the enlarged upper end portion of the small punch. A center
holding pin 85 is telescoped into a vertical hole 86 formed in the
top of the punch to hold the spacer against the top surface of the
head of the punch. When the punch is positioned in the adapter, the
top surface of the slug is flush with the top surface of the
adapter as shown in FIGS. 8 and 9 so that the lower end portion 50
of the ram 23 engages the top surface of the spacer as the holder
is moved upwardly on the ram to lock the punch unit in the
holder.
The small punch 69, the adapter sleeve 70 and the spacer 71 thus
form a punch unit which is substantially the same size as the large
punch 21 so that the small punch may be fitted into and locked in
the same holder 20 as the large punch. In the appended claims, the
terms "punch unit" are intended to encompass both a punch per se
and a punch assembly with a punch whose effective size is increased
by virtue of attaching elements such as an adapter, a spacer or the
like to the punch.
* * * * *