Information
-
Patent Grant
-
6557390
-
Patent Number
6,557,390
-
Date Filed
Friday, May 11, 200123 years ago
-
Date Issued
Tuesday, May 6, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 072 4811
- 072 4812
- 072 4816
- 072 4817
- 072 4821
- 072 4822
- 072 4826
- 072 4819
-
International Classifications
-
Abstract
A tool holder apparatus for a press brake is provided. The apparatus comprises a support plate having a first receiving surface. A pivotable clamp has an engagement portion that is moveable toward the first receiving surface of the support plate by pivoting the clamp. The engagement portion has therein formed a bore in which a lifting shaft is rotatably received. The engagement portion defines an opening communicating with the bore. The shaft has therein formed a notch that is adapted to be engaged through the opening by an exterior corner of a forming tool. The notch is configured such that when the engagement portion of the clamp is forced against such tool, a first surface of the exterior tool corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a second surface of the exterior tool corner and delivering to the tool a mounting force having a component normal to the second surface of the exterior tool corner.
Description
FIELD OF THE INVENTION
The present invention relates to press brakes of the type used to shape sheet-like workpieces. More particularly, this invention relates to press brake tool holders that are used to releasably retain forming tools in a press brake.
BACKGROUND
Press brakes are commonly used to shape sheet-like workpieces, such as sheet metal and the like. A conventional press brake includes an upper table and a lower table, at least one of which is movable toward and away from the other. Typically, the upper table is movable vertically, while the lower table is fixed in a stationary position. It is common for a male forming tool and a female forming die to be carried respectively by the upper and lower tables of a press brake.
Typically, the forming tool has a downwardly-oriented workpiece-deforming surface (or tip). The configuration of this surface is dictated by the shape into which it is desired to bend workpieces. The forming die has a recess that is aligned with the workpiece-deforming surface of the tool. The configuration of the recess corresponds to that of the workpiece-deforming tool surface. Thus, when the tables are brought together, a workpiece between the two is pressed by the tool into the die to give the workpiece the desired bend.
Various tool holders have been devised to mount a forming tool to the upper table of a press brake. For example, U.S. Pat. No. 5,619,885, the teachings of which are incorporated herein by reference, discloses a tool holder with a tool clamp member that is pivotally attached to a stationary support plate. During use, the clamp member exerts a clamping force upon the shank of a forming tool. To keep the tool from falling when the clamping force is released, the clamp member is provided with a projection that is engageable with a complementary drop-prevention groove formed in the tool.
In order to accurately deform workpieces, it is necessary for the forming tool to be mounted securely to the tool holder. This is accomplished by forcibly clamping the tool holder to the forming tool (i.e., by applying a clamping force to the tool). Multiple steps are typically required to operatively mount a forming tool on a conventional tool holder. This is perhaps best understood with reference to
FIGS. 1-3
, which illustrate a particularly useful press brake tool holder. The illustrated tool holder is disclosed in U.S. Pat. No. 6,003,360, the teachings of which are incorporated herein by reference.
As illustrated in
FIG. 1
, the forming tool
28
is initially mounted loosely to the tool holder
10
. Specifically, the mounting tang
30
of the tool
28
is lifted upwardly between a support plate
14
and a clamp
42
of the tool holder
10
. As the tool
28
is moved into the unclamped position illustrated in
FIG. 1
, a safety slot
122
on the tool
28
is engaged by a lip
116
of the clamp
42
. Thus, the tool
28
is prevented from falling from the holder
10
by the engagement of the lip
116
and the safety slot
122
. Although the tool
28
is retained loosely by the holder
10
in this position, it is not operatively clamped therein. Specifically, the load-bearing surfaces
24
,
26
of the support plate
14
and forming tool
28
are not brought into secure engagement with one another by simply mounting the tool
28
in its unclamped position. Rather, additional steps are required to mount the tool
28
in its operative position.
The upper and lower tables of the press brake are subsequently moved together until the forming tool comes into contact with a forming die on the lower table. This is best understood with reference to
FIG. 2
, wherein the tip
38
of the loosely-mounted tool
28
has been moved into engagement with a forming die
168
on the lower table (not shown). By forcing the tip
38
of the tool
28
against the die
168
, the tool
28
is urged upwardly relative to the tool holder
10
until the load-bearing surface
26
of the tool
28
is moved into contact with the load-bearing surface
24
of the support plate
14
.
At this point, the tool
28
can be forcibly clamped (or locked) in its operative position. While maintaining the tool
28
in the position shown in
FIG. 2
, the lower portion
68
of the clamp
42
is pivoted toward the tool
28
. As this portion
68
of the clamp
42
closes upon the shank
30
of the tool
28
, the tool is clamped securely to the holder.
FIG. 3
illustrates the resulting operative position, wherein the load bearing surfaces
24
,
26
of the support plate
14
and the tool
28
are engaged and the mounting shank
30
of the tool
28
is forcibly clamped between the support plate
14
and the lower portion
68
of the clamp
42
. During operation, the tool holder
10
is locked in this clamped position. Thus, it can be seen that several steps are typically required to operatively mount a forming tool upon a tool holder.
It would be desirable to provide a tool holder that can be operatively clamped about a forming tool in such a way that the load-bearing surfaces of the tool and the holder are engaged as an adjunct of the clamping action of the tool holder (i.e., without having to press the tip of the loosely-clamped tool against a die on the lower table of the press brake).
SUMMARY OF THE INVENTION
A tool holder apparatus for a press brake is provided in a first embodiment of the present invention. The apparatus comprises a support plate having a first receiving surface. A pivotable clamp has an engagement portion that is moveable toward the first receiving surface of the support plate by pivoting the clamp. The engagement portion has therein formed a bore in which a lifting shaft is rotatably received. The engagement portion defines an opening communicating with the bore. The shaft has therein formed a notch that is adapted to be engaged through the opening by an exterior corner of a forming tool. The notch is configured such that when the engagement portion of the clamp is forced against such tool, a first surface of the exterior tool corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a second surface of the exterior tool corner and delivering to the tool a mounting force having a component normal to the second surface of the exterior tool corner.
In another aspect of the invention, there is provided a tool holder assembly for a press brake. The assembly comprises a support plate having a first receiving surface and a load-bearing receiving surface. A forming tool has a first mounting surface on a first side thereof and an exterior corner (i.e., an exterior tool corner) on a second side thereof. The first mounting surface of the tool is engaged with the first receiving surface of the support plate. The tool has a load-bearing mounting surface forming an included right angle with the first mounting surface. The load-bearing mounting surface is adapted to engage the load-bearing surface of the support plate. A pivotable clamp has an engagement portion that is moveable toward the first receiving surface by pivoting the clamp. The engagement portion has therein formed a bore in which a lifting shaft is rotatably received. The engagement portion defines an opening communicating with the bore. The shaft has therein formed a notch that is adapted to be engaged through the opening by the exterior corner of the forming tool. The notch is configured such that when the engagement portion of the clamp is forced against the tool, a first surface of the exterior tool corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a second surface of the exterior tool corner. Thus, delivering to the tool a mounting force having a component normal to the second surface of the exterior tool corner.
In still another aspect of the invention, there is provided an upper press brake assembly. The assembly comprises an upper press brake table including a tool holder body. A support plate forms part of the tool holder body and has a first receiving surface and a generally downward-facing load-bearing receiving surface. The receiving surfaces of the support plate together define an exterior corner. A forming tool has a first mounting surface on a first side thereof and an exterior corner (i.e., an exterior tool corner) defined by first and second corner surfaces on a second side thereof. The second corner surface is generally-downwardly-facing. The first mounting surface of the tool is engaged with the first receiving surface of the support plate. The tool has a load-bearing mounting surface forming an included angle with the first mounting surface and being adapted to engage the generally downward-facing load-bearing receiving surface of the support plate. A clamp is attached pivotally to the tool holder body and has an engagement portion that is moveable toward the first receiving surface by pivoting the clamp. The engagement portion has therein formed a bore in which a lifting shaft is rotatably received. The engagement portion defines an opening communicating with the bore. The shaft has therein formed a notch that is adapted to be engaged through the opening by the exterior corner of the tool. The notch is configured such that when the engagement portion of the clamp is forced against the tool, the first corner surface bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against the second corner surface. Thus, delivering to the tool a mounting force having a generally-upward component.
A tool holder apparatus for a press brake is provided in yet another aspect of the invention. The apparatus comprises a support plate having a first receiving surface and a generally downward-facing receiving surface. These receiving surfaces together define an exterior corner. A pivotable clamp has an engagement portion that is moveable toward the first receiving surface by pivoting the clamp. The engagement portion has therein formed a bore in which a lifting shaft is rotatably carried. The engagement portion defines a slot communicating with the bore. The shaft has therein formed a notch that is adapted to be engaged through the slot by an exterior corner of a forming tool a mounting tang of which is positioned between the first receiving surface of the support plate and the engagement portion of the clamp. The notch is configured such that when the engagement portion of the clamp is forced against such tool, a generally-vertical surface of the exterior corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a generally-downward-facing surface of the exterior corner and delivering to the tool a mounting force having a generally-upward component.
A tool holder apparatus for a press brake is provided in still another aspect of the invention. The apparatus comprises a support plate having a first receiving surface. A clamp has an engagement portion defining a slot communicating with a bore formed in the clamp. A lifting shaft is rotatably received in the bore. The shaft has therein formed a notch that can be engaged through the slot by an exterior corner of a forming tool. The notch is configured such that when it is forced against the exterior corner, a first surface of the exterior corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a second surface of the exterior corner. Thus, delivering to the tool a mounting force having a component normal to the second surface of said exterior corner.
In yet another aspect of the invention, there is provided a press brake assembly. The assembly comprises an upper press brake table including a tool holder body and a lower press brake table including a forming die. A support plate forms part of the tool holder body and has a first receiving surface and a load-bearing receiving surface. These receiving surfaces together form an exterior corner. A forming tool has a first mounting surface on a first side thereof and an exterior corner defined by first and second corner surfaces on a second side of the tool. The first mounting surface is engaged with the first receiving surface of the support plate. The tool has a load-bearing mounting surface forming an included angle with the first mounting surface. The load-bearing mounting surface is adapted to engage the load-bearing surface of the support plate. The tool has a workpiece-deforming surface oriented downwardly toward the forming die. A clamp is attached pivotally to the tool holder body and has an engagement portion that is moveable toward said first receiving surface by pivoting the clamp. The engagement portion has therein formed a bore in which an elongated shaft is rotatably received. The engagement portion defines an opening communicating with the bore. The shaft has therein formed a notch that is adapted to be engaged through the opening by the exterior corner of the tool. The notch is configured such that when the engagement portion of the clamp is forced against the tool, the first corner surface bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against the second corner surface and delivering to the tool a mounting force having a component normal to the second corner surface. Thus, the load-bearing surfaces can be engaged with one another by forcing the engagement portion of the clamp against the tool without forcing the workpiece-deforming surface of the tool against the forming die on the lower table.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a cross-sectional end view of a prior art tool holder depicted in its unclamped position;
FIG. 2
is a cross-sectional end view of the unclamped tool holder of
FIG. 1
in which the tool holder is depicted in engagement with a forming die;
FIG. 3
is a cross-sectional end view of the tool holder of
FIG. 1
in which the tool holder is depicted in its clamped position;
FIG. 4
is a cross-sectional end view of a tool holder in accordance with one embodiment of the present invention;
FIG. 5A
is a cross-sectional end view of a tool holder in accordance with another embodiment of the invention;
FIG. 5B
is a cross-sectional end view of a tool holder in accordance with still another embodiment of the invention;
FIG. 5C
is a cross-sectional end view of a tool holder with yet another embodiment of the invention;
FIG. 6
is a perspective of a tool holder with attached tooling in accordance with still another embodiment of the invention;
FIG. 7
is an exploded perspective view of the tool holder of
FIG. 6
;
FIG. 8
is a cross-sectional end view of the tool holder of
FIG. 4
in which the tool holder is depicted in an unclamped position about a forming tool;
FIG. 9
is a close-up end view of the unclamped tool holder of
FIG. 8
;
FIG. 10
is a cross-sectional end view of the tool holder of
FIG. 8
in which the tool holder is depicted mounted to the beam of a press brake and clamped about the forming tool;
FIG. 11
is a close-up end view of the clamped tool holder of
FIG. 10
;
FIG. 12
is an exploded perspective view of a tool holder clamp in accordance with a preferred embodiment of the invention;
FIG. 13
is an end view of the engagement portion of the tool holder clamp of
FIG. 12
;
FIG. 14A
is a perspective view of the lifting shaft of the tool holder clamp of
FIG. 12
;
FIG. 14B
is a cross-sectional view of the lifting shaft of
FIG. 14A
, taken along line
14
B—
14
B of
FIG. 14A
;
FIG. 15A
is an end view of a lifting shaft in accordance with another embodiment of the invention;
FIG. 15B
is an end view of a lifting shaft in accordance with still another embodiment of the invention;
FIG. 16A
is an end view of a lifting shaft in accordance with yet another embodiment of the invention;
FIG. 16B
is an end view of a lifting shaft in accordance with still another embodiment of the invention;
FIG. 16C
is an end view of a lifting shaft in accordance with yet another embodiment of the invention; and
FIG. 17
is a perspective, broken-away schematic view of the tool holder of
FIG. 6
in which is depicted removal of tooling from the holder.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 4
illustrates a tool holder
10
in accordance with a preferred embodiment of the present invention. The illustrated tool holder
10
is not carrying a forming tool (i.e., the holder is depicted in an unloaded position). The tool holder
10
generally includes a holder body
12
and at least one clamp
42
. As is typical, the illustrated tool holder
10
includes two clamps
40
,
42
mounted on opposite sides of the holder body
12
. However, the tool holder can alternatively be provided with a single clamp, as discussed below.
The tool holder
10
shown in
FIG. 4
has a composite holder body
12
. That is, the holder body
12
is an assembly of multiple plates. Specifically, the illustrated holder body
12
includes a support plate
14
to which is joined a mount plate
16
. The support plate
14
and the mount plate
16
have generally vertical surfaces
18
,
20
, respectively, that are contiguous (i.e., abutting). When a composite holder body
12
of this nature is employed, the mount plate
16
can be joined to the support plate
14
by any desired fastening means. For example, they can be joined together by one or more threaded bolts (not shown). A variety of other conventional fasteners can also be used.
While
FIG. 4
illustrates a particularly useful composite holder body
12
, the present invention does not require a holder body of any particular structure. For example,
FIG. 5A
illustrates another particularly useful holder body
212
, which has a slightly different structure than that shown in FIG.
4
. This body
212
is also an assembly of multiple plates. It is noted that the reference numerals in
FIGS. 5A
,
5
B, and
5
C are indexed respectively by factors of
200
,
300
, and
400
over the reference numerals that identify analogous features in FIG.
4
. With reference to
FIG. 5A
, a mount plate
216
is joined to a support plate
214
in much the same manner as depicted in FIG.
4
. However, the mount plate
216
shown in
FIG. 5A
has a slightly different configuration than that of FIG.
4
. Specifically, the upper end
219
of the mount plate
216
shown in
FIG. 5A
is not as wide as the upper end
19
of the mount plate
16
shown in FIG.
4
. This provides a wider horizontal surface
215
against which the beam of an upper press brake table (not shown) can be mounted.
While
FIGS. 4 and 5A
illustrate composite tool holder bodies, the present invention is by no means limited to use with a holder body formed of multiple plates. For example, the holder body can be formed of a single plate.
FIG. 5B
illustrates one such embodiment, wherein the holder body
312
is formed of an integrally-constructed plate
314
. The configuration and relative dimensions of this holder body
312
are similar to those of the holder body
12
shown in FIG.
4
. For example, the holder body
312
has an upper extension
319
configured and dimensioned much like the upper end
19
of the mount plate
16
shown in FIG.
4
. This extension
319
forms an included right angle together with the upper surface
315
of the holder body
312
, hence facilitating mounting of the tool holder to an upper press brake table.
FIG. 5C
illustrates yet another holder body that is useful with the present invention. This holder body
412
, like that shown in
FIG. 5B
, is formed of a single plate
414
. However, the configuration and relative dimensions of this holder body
412
are similar to those of the holder body
212
in FIG.
5
A. For example, the upper extension
419
of the holder body
412
has the same relative width as the upper end
219
of the mount plate
216
shown in FIG.
5
A. Of course, those skilled in the art would readily appreciate a variety of other body structures that would be useful with the present invention.
Regardless of the particular structure of the holder body, the tool holder includes a shoulder extending from the holder body. For example, the support plate shown in
FIG. 4
includes a downward-facing shoulder that is adapted to engage an upward-facing shoulder of a forming tool (not shown). The downward-facing shoulder of the support plate
14
terminates in a load-bearing receiving surface
24
. This surface
24
of the support plate
14
is adapted to deliver downward force to a forming tool operatively mounted to the tool holder. As is discussed below in further detail, the load-bearing surface
24
of the support plate
14
is desirably maintained flush against a load-bearing surface of the forming tool during operation of the press brake. If so desired, the downwardly facing shoulder
17
can additionally, or alternatively, be employed as a load bearing surface.
The support plate
14
includes a first receiving surface
34
against which the mounting shank of a forming tool can be positioned. As illustrated in
FIG. 4
, the first receiving surface
34
arises along the front side (i.e., the side oriented toward the handle
82
) of the downward-facing shoulder of the support plate
14
. This receiving surface
34
forms an exterior corner together with the load-bearing surface
24
of the support plate
14
. In further detail, the first receiving surface
34
is typically a generally vertical surface that defines a normal exterior corner with the load-bearing receiving surface
24
. Accordingly, the load-bearing receiving surface
24
is typically a generally horizontal, downward-facing surface.
With continued reference to
FIG. 4
, receiving surfaces
34
,
36
arise along both sides of the downward-facing shoulder of the support plate
14
. Thus, a forming tool can be mounted on the tool holder
10
in two different positions. Specifically, a tool can be clamped either between the first clamp
42
and the first receiving surface
34
, or between the second clamp
40
and the second receiving surface
36
. As noted above, however, the tool holder
10
can alternatively be provided with a single clamp by simply omitting one of the clamps or by redesigning the tool holder such that only one side of the support plate has a useful vertical receiving surface. Variations of this nature will be obvious to those skilled in the art.
The tool holder includes at least one clamp that is adapted to forcibly retain the shank of a forming tool against the support plate. As noted above, the tool holder will typically be provided with two clamps mounted on opposite sides of the holder body. For example, with reference to
FIG. 4
, the first clamp
42
(i.e., the clamp on the front side of the tool holder) is mounted to the mount plate
16
, while the second clamp
40
is mounted to the support plate
14
. Each clamp is advantageously formed of two half units. This is perhaps best understood with reference to
FIG. 7
, which illustrates an exploded view of a preferred tool holder of the invention. In further detail, the first clamp
42
is composed of a first unit half
44
and a second unit half
46
, and the second clamp
40
is composed of a first unit half
48
and a second unit half
50
.
FIG. 6
illustrates the resulting assembly of the tool holder
10
.
In the preferred embodiment illustrated in
FIG. 4
, each clamp has an upper portion
66
and a lower portion
68
and is pivotally attached therebetween to the holder body
12
. For example, the first clamp
42
is pivotally attached to the holder body
12
in such a way that the engagement portion
67
of the clamp
42
is moveable selectively toward or away from the first receiving surface
34
of the support plate
14
. As discussed below, this is accomplished by pivoting the clamp
42
, either in the clockwise direction (as seen in
FIG. 4
) to move the lower end
68
of the clamp
42
toward the support plate
14
, or in the counterclockwise direction to move the lower end
68
of the clamp
42
away from the support plate
14
. Thus, the engagement portion
67
of the clamp
42
is adapted to contact the mounting shank of a tool (not shown) when the tang of such tool is positioned between support plate
14
and the clamp
42
.
Preferably, each clamp is attached pivotally to the tool holder body
12
. In particularly preferred embodiments, each clamp is pivotally attached to the holder body
12
by a plurality of pins
52
, each extending from the clamp and terminating in an enlarged head
56
received in a recess defined by the holder body
12
, or vice versa. That is, each pin
52
can alternatively extend from the holder body
12
and terminate in a recess defined by the clamp. Either way, the enlarged heads
56
and the respective recesses are shaped so as to articulate together when the clamp is made to pivot.
The former arrangement is illustrated in
FIG. 7
, wherein each clamp half unit is provided with a pair of spaced-apart pins
52
. Each pin
52
has a threaded end
54
that is received in a threaded bore formed in the clamp. Each pin
52
also has an enlarged, rounded head
56
that is received in a slotted aperture defined by the holder body
12
. With continued reference to
FIG. 7
, the mount plate
16
and the support plate
14
each include a plurality of spaced-apart apertures
58
that are aligned horizontally to define an axis about which the first
42
and second
40
clamps are respectively adapted to pivot. Each aperture
58
forms a horizontally elongated slot having an enlarged end opening
60
and an undercut slot portion
62
. The enlarged heads
56
of the pins are sized so as to be received through the enlarged end openings
60
of the slots. When in this position, the individual clamps can be moved horizontally toward the center line of the tool, thus sliding the enlarged heads into engagement with the undercut surfaces
62
of the slots. In this manner, each clamp half can be released from the tool holder by sliding the clamp half horizontally away from the center of the tool until the pins are aligned with the enlarged openings
60
, whereupon the clamp halves can simply be removed from the holder body.
A series of compression springs
64
are advantageously mounted between the confronting surfaces of each clamp and the holder body. These springs
64
tend to urge the clamps away from the holder body so that each clamp is tethered to the body by the pins
52
. The confronting surfaces of each clamp and the holder body are provided with seating recesses to receive and support the ends of the springs. With respect to the embodiment of
FIG. 4
, the pins
52
separate each clamp into an upper portion
66
and a lower portion
68
. Thus, when the upper portion
66
of a clamp is moved away from the holder body
12
, the lower portion
68
of the clamp is conjointly moved toward the holder body
12
. This pivoting occurs about the axes defined by the centers of the enlarged pin heads
56
.
Any desired actuator can be used to cause a clamp of the present invention to pivot. As is perhaps best seen in
FIG. 7
, a preferred actuator mechanism involves a cam shaft. In more detail, a horizontal bore
70
is formed through the length of the support plate
14
. Rotatably fitted within the bore
70
is a cam shaft
72
. The cam shaft
72
has a generally circular cross section along its length and includes spaced camming sections, which can be oval or generally elliptical as shown at
74
. The midsection of the cam shaft is provided with a flat surface having a bore
76
threaded to receive the threaded end
78
of a handle
80
. With continued reference to
FIG. 7
, the handle
80
preferably comprises a composite handle assembly. For example, the illustrated handle assembly includes a manually-operable knob
82
at one end, an exteriorly threaded end portion
78
on a handle segment
84
at the opposite end, and an intermediate shaft portion
86
that is telescopically received within a bore
88
in the handle segment
84
. The intermediate shaft portion
86
is preferably releasably held in the bore
88
by a resilient O-ring
90
. In the illustrated embodiment, the support plate
14
is provided with a central, vertical slot
92
at its upper edge such that when the cam shaft is fully received within the bore
70
and the threaded end
78
of the handle is received in the threaded hole
76
, the handle can be moved upwardly and downwardly through the slot
92
. Likewise in the illustrated embodiment, an elongated slot
94
is formed through the thickness of the mount plate
16
in alignment with the slot
92
. The handle
80
passes through the slot
94
, which allows the handle to be moved easily between a lower position (shown in
FIG. 8
) and an upper position (shown in FIG.
10
), the handle being thus moved in a plane perpendicular to the axis of the cam shaft
72
. The half units
44
,
46
of the illustrated first clamp
42
have confronting recessed surfaces
98
that define an upwardly open slot on the front of the tool holder
10
when the half units are joined, thus enabling motion of the handle in the manner just described.
With reference to the embodiment of
FIGS. 6-8
, it can be seen that aligned bores are formed transversely through the thickness of the support plate
14
and mount plate
16
. These bores intersect the bore
70
in which the cam shaft
72
is received. These transverse bores are in line with the portions of the cam shaft that include the camming surfaces
74
. The transverse bores formed in the support plate are designated by the reference numeral
100
, and those in the mounting plate by the reference numeral
102
. Within the transverse bores are positioned sliding cam follower pins that extend between the camming sections
74
of the cam shaft and the upper portions of the clamps. The cam follower pins between the cam shaft and the clamp
40
are designated
104
and the cam follower pins between the cam shaft and the clamp
42
are designated
106
. Preferably, the ends of the cam follower pins that engage the oval camming surfaces of the cam shaft are slightly concave, whereas the outer ends of the cam follower pins are preferably slightly convex so as to engage hemispherical recesses
108
formed in the confronting surfaces of the clamps.
As noted above, there is provided at least one clamp having an engagement portion that is moveable toward the support plate and is adapted to engage the tang of a forming tool positioned against the support plate. In embodiments of the invention wherein each clamp has an upper portion
66
and a lower portion
68
and is attached pivotally therebetween to the holder body
12
, the engagement portion
67
of each clamp will typically be on the lower portion
68
of the clamp. In the embodiment of
FIG. 4
, the engagement portion
67
of the clamp
42
includes a contact surface
96
that is adapted to bear against the mounting shank of a forming tool (not shown) positioned between the clamp and the downwardly-extending shoulder of the support plate
14
.
The engagement portion
67
of at least one of the clamps has therein formed a bore
93
that is adapted to rotatably receive a lifting shaft
75
. As is perhaps best understood with reference to
FIGS. 12 and 13
, the bore
93
preferably extends along substantially the entire longitudinal length of the engagement portion
67
of the clamp
42
. With reference to
FIG. 13
, the bore
93
is defined by an interior surface
95
of the clamp
42
. The configuration of this interior surface
95
is such that the bore
93
is adapted to rotatably carry the lifting shaft
75
. Most preferably, this interior surface
95
is shaped so as to define a semi-circle in cross-section, thereby allowing an appropriately dimensioned cylindrical lifting shaft
75
to be rotatably received in the bore
93
. Preferably, the arcuate extent of the interior bore surface
95
is greater than 180°, so that the interior bore surface
95
will embrace more than half of the circumferential extent of an appropriately dimensioned lifting shaft
75
, thus ensuring the lifting shaft
75
is maintained within the bore
93
.
In preferred embodiments of the invention, the engagement portion
67
of the clamp
42
defines an opening communicating with the bore
93
. With reference to
FIG. 13
, it can be seen that the bore
93
opens through a wall of the clamp
42
. Specifically, the bore
93
opens through the wall that defines the contact surface
96
. Thus, when the clamp
42
is mounted to the holder body
12
, the opening of the bore
93
is oriented generally toward the support plate
14
. This opening can also be characterized as a longitudinally-extending slot that communicates with the bore
93
. With continued reference to
FIG. 13
, the slot is bounded on one side by an exterior corner formed by the intersection of the interior bore surface
95
and the contact surface
96
of the clamp
42
. On its other side, the slot is bounded by a lip-like structure
97
between the interior bore surface
95
and the upwardly and sidewardly sloped surface
91
of the clamp
42
.
As noted above, the bore
93
is configured to rotatably carry the elongated lifting shaft
75
. The relative dimensions of the bore
93
and the shaft
75
are selected such that the shaft
75
is allowed to rotate about its central axis within the bore
93
, yet is prevented from escaping through the opening (or slot) of the bore
93
. Thus, when the shaft
75
and the bore
93
are both circular in cross-section, the shaft
75
preferably has an outer diameter that is less than the inner diameter of the bore
93
, but greater than the width of the bore opening. Preferably, the outer dimension of the shaft
75
is slightly less than, and perhaps optimally substantially the same as, the inner dimension of the bore
93
. For example, when the lifting shaft
75
is cylindrical, the shaft
75
and the bore
93
are preferably dimensioned such that the inner surface
95
of the bore
93
is slidingly contiguous with the side
77
of the shaft
75
.
As is perhaps best understood with reference to
FIGS. 9 and 11
, the lifting shaft
75
has therein formed a notch
21
that is adapted to be engaged through the opening of the bore by an exterior corner of a forming tool. The exterior corner (i.e., the exterior tool corner) is defined by first
123
and second
127
corner surfaces. The notch is advantageously configured such that when the engagement portion of the clamp is forced against such tool, the first corner surface
123
bears against a first surface portion
23
of the notch
21
and causes the shaft
75
to rotate about its axis within the bore
93
, thereby bringing a second surface portion
27
of the notch
21
to bear against the second corner surface
127
. Thus, a mounting force having a component normal to the second corner surface
127
is delivered to the tool
28
.
As is best seen in
FIG. 12
, the notch
21
preferably extends along the entire longitudinal length of the lifting shaft
75
. With reference to
FIG. 14B
, the notch
21
spans an angle
29
of less than
900
, as measured from the central axis (or “longitudinal axis”) of the shaft
75
. While any acute notch angle
29
will enable the lifting function of the shaft
75
, a notch angle of less than about 75°, perhaps optimally equal to about 60°, will enhance the lifting operation of the shaft
75
. Moreover, a notch angle
29
of at least about 45° will facilitate engaging the notch
21
with an exterior corner of a forming tool, as discussed below.
In cross-section, the notch
21
preferably has a generally “V”-shaped configuration. However, this is certainly not a requirement, as many other notch configurations would be useful as well. For example, the notch
21
can alternatively have a semi-circular cross-sectional configuration (as shown in FIG.
16
A). In another embodiment, the notch
21
is “U”-shaped in cross-section (as shown in FIG.
16
B). Still another embodiment involves a notch
21
with a generally square cross-sectional configuration (as shown in FIG.
16
C). A variety of other suitable notch configurations would be obvious to those skilled in the present art.
The notch
21
is defined by at least one notch surface.
FIGS. 15B and 16A
illustrate embodiments wherein the notch
21
is defined by a single surface. Alternatively, the notch
21
can be defined by two surfaces, as illustrated in FIGS.
15
A.
FIGS. 14B
,
16
B, and
16
C illustrate embodiments wherein the notch
21
is defined by three surfaces. Regardless of the particular number of notch surfaces, the notch
21
includes first
23
and second
27
surface portions that are adapted to engage an exterior corner of a forming tool, as discussed below.
FIG. 12
illustrates a particularly preferred manner of incorporating the lifting shaft
75
into a clamp
42
of the invention. It is advantageous to limit the rotational freedom of the lifting shaft
75
within the bore
93
. Specifically, it is desirable to secure the lifting shaft
75
within the bore
93
in such a way that the shaft
75
is prevented from rotating into an orientation wherein the notch
21
is concealed entirely by the inner bore surface
95
. In other words, it is desirable to limit the shaft
75
to a range of rotation in which, at all possible shaft
75
orientations, at least a portion of the notch
21
is exposed through the bore opening (or slot). Optimally, the shaft
75
is limited to a range of rotation in which the entire notch
21
is exposed through the bore opening at all possible orientations.
With reference to
FIG. 12
, it can be seen that the rotational freedom of the lifting shaft
75
can be limited by one or more set pins
55
. The illustrated clamp
42
embodiment employs two set pins
55
secured within transverse bores
51
opening through the surface
95
of the longitudinal bore
93
. When the pins
55
are seated respectively in the transverse bores
51
, a portion of each pin
55
projects diametrically from the transverse bore
55
and beyond the surface
95
of the longitudinal bore
93
. This projection of each set pin
55
is adapted to engage a transverse groove
59
formed in the lifting shaft
75
. Thus, when the lifting shaft
75
is within the longitudinal bore
93
, the set pins
55
are received in the respective transverse grooves
59
in the lifting shaft
75
. Rotation of the shaft
75
far enough in either direction (i.e., clockwise or counterclockwise) brings the set pins
55
into contact with the transverse groove surfaces, thus limiting rotational of the shaft
75
. It is also noted that the set pins
55
prevent the shaft
75
from sliding longitudinally out of the bore
93
.
In particularly preferred embodiments, the lifting shaft
75
is urged into a desired default orientation when the clamp
42
is not engaged with a forming tool. With reference to
FIG. 4
, the lifting shaft
75
of the clamp
42
is depicted in a default orientation that is favorable for initiating clamping action of the tool holder
10
. In this orientation, the notch
21
is readily engagable with the exterior corner
124
(or shoulder) above the safety slot
122
of a conventional forming tool (not shown). In further detail, the second surface portion
27
of the thus oriented notch
21
is generally horizontal. Thus, when a tool
28
is lifted into the unclamped position depicted in FIG.
9
and then released, the second surface portion
27
of the notch
21
is adapted to catch (i.e., engage) the downward-facing surface
127
of the shoulder
124
above the safety slot
122
.
With reference to
FIG. 12
, it can be seen that a spring can be used to retain the lifting shaft in a desired orientation when the clamp is not engaged with a tool. In the illustrated embodiment, a leaf spring
33
is positioned between the lifting shaft
75
and the inner surface
95
of the longitudinal bore
93
. In further detail, the leaf spring
33
is an elongated body of resilient material (e.g., metal or plastic) that assumes an arcuate (i.e., curvedly bent) configuration when uncompressed. The leaf spring
33
is sufficiently thin to be positioned between the shaft
75
and the inner surface
95
of the bore
93
. A central portion of the leaf spring
33
is positioned in a notch
37
formed in the interior surface
95
of the longitudinal bore
93
. While the spring
33
can be secured in this notch
37
by means of soldering, adhesives, or the like, this is not believed to be necessary as the spring
33
will effectively be trapped in the notch
37
when the lifting shaft
75
is within the bore
93
.
With reference to
FIG. 14A
, it is seen that a groove
73
can be formed in the side
77
of the lifting shaft
75
to facilitate use of the leaf spring
33
. The groove
73
is configured to receive the leaf spring
33
when the shaft
75
and spring
33
are both within the bore
93
. Preferably, the groove
73
is long enough to receive the entire length of the leaf spring
33
when the spring
33
is fully compressed. The compressed spring
33
bears against a surface
71
of the groove
73
, thereby delivering a spring force to the lifting shaft
75
. This force urges rotation of the lifting shaft
75
toward the desired default orientation. With reference to
FIG. 4
, the ends of the spring
33
bear against the groove surface
71
in the lifting shaft
75
, thereby urging rotation of the shaft
75
in the counterclockwise direction (as seen in FIG.
4
). The lifting shaft
75
is prevented from rotating too far (i.e., past the default orientation) by the rotational limits defined by the pins
55
. Thus, rotation of the lifting shaft
75
in the counterclockwise direction (as seen in
FIG. 4
) is stopped when the pins
55
are engaged by the surfaces of the transverse grooves
59
in the shaft
75
. It is noted that the ends of the leaf spring
33
are preferably flattened (i.e., not arcuate) to provide better contact with the surface
71
of the groove
73
.
The lifting action of the shaft
75
is best understood with reference to
FIGS. 8-11
, which depict operation of a particularly preferred tool holder of the invention. With reference to
FIG. 8
, the tool holder
10
is depicted in an unclamped position about a forming tool
28
. The mounting tang
30
of the tool
28
is positioned between the support plate
14
and the engagement portion
67
of the clamp
42
. In further detail, a first side of the tool
28
includes a first mounting surface
32
that is engaged with the first receiving surface
34
of the support plate
14
. A second side of the tool
28
includes a safety slot
122
above which is formed an exterior corner
124
(or shoulder) that is adapted to engage the notch
21
in the lifting shaft
75
. The illustrated tool
28
also includes a load-bearing mounting surface
26
that forms an included right angle with the first mounting surface
32
. The load-bearing surface
26
of the tool
28
is adapted to engage the load-bearing surface
24
of the support plate
14
. However, the tool holder
10
of
FIG. 8
is depicted in its unclamped position, wherein the load-bearing surfaces of the tool and the support plate are not engaged.
As is perhaps best understood with reference to
FIG. 9
, the tool holder
10
prevents the tool
28
from falling from the holder
10
, even when the holder is in its unclamped position. The clamp
42
preferably has an inwardly-turned lip
97
at its lower end. As noted above, this lip
97
embraces a sufficient circumferential extent of the lifting shaft
75
to prevent the shaft
75
from escaping through the opening (or slot) of the bore
93
. With continued reference to
FIG. 9
, it can be seen that the lifting shaft
75
projects somewhat from the bore opening. In further detail, the notched portion of the shaft
75
projects generally inwardly (i.e., toward the support plate) beyond the contact surface
96
of the clamp
42
.
When a forming tool
28
is lifted into the position depicted in
FIG. 9
, the mounting tang
30
of the tool
28
engages the upwardly and inwardly sloped surface
91
of the lip
97
, thereby urging the lower portion
68
of the clamp
42
away from the support plate
14
. This causes the clamp
42
to pivot about its attachment to the holder body
12
in a counter-clockwise direction (as seen in
FIG. 9
) until there is provided enough clearance for the mounting tang
30
of the tool
28
to pass between the clamp
42
and the support plate
14
.
As the mounting tang
30
of the tool
28
is moved far enough upward to bring the downward and sideward facing shoulder
124
of the tool
28
into alignment with the notch
21
, the lower end
68
of the clamp
42
is urged back toward the support plate
14
by the springs
64
(in cooperation with the mounting pins and slots). This brings the notch
21
into engagement with the shoulder
124
of the tool
28
. Thereafter, when the tool
28
is released and urged downward under its own weight, the downward-facing surface
127
of the safety slot
122
bears against the second surface portion
27
of the notch
21
.
It is noted that when the tool holder
10
is in its unclamped position about a tool
28
, the springs
64
advantageously cooperate with the mounting pins
54
and slots to resiliently maintain engagement of the clamp
42
and the tool
28
. In further detail, the clamp
42
is advantageously maintained in a position wherein the spacing between the first receiving surface
34
of the support plate
14
and the lip
97
of the clamp
42
is slightly less than the width of the tool shank
30
. Thus, the lip
97
and part of the second surface portion
27
of the notch
21
are at least loosely seated in the safety slot
122
, thereby preventing the forming tool
28
from falling from the tool holder even when the clamp
42
is in its unlocked (i.e., unclamped) position.
As noted above, the lifting shaft
75
is desirably restrained to a limited range of rotation such that the second surface portion
27
of the notch
21
is not allowed to rotate beyond the lip
97
of the clamp
42
. When the tool holder
10
is in its unclamped position about a forming tool
28
(as depicted in FIG.
9
), the weight of the tool
28
acting upon the second surface portion
27
of the notch
21
preferably does not cause the shaft
75
to rotate so far as to bring the downward-facing safety slot surface
127
into contact with the lip
97
of the clamp
42
. Of course, this is not a requirement, as the lifting shaft
75
would not rotate much beyond this point even in cases where the shaft
75
has an unlimited range of rotation. In such cases, the lip
97
of the clamp
42
would eventually catch the downward-facing safety slot surface
127
, thereby preventing further downward movement of the tool, hence limiting counterclockwise rotation of the shaft. Limiting the rotation of the lifting shaft
75
is beneficial, though, as it facilitates establishing a default notch orientation, as discussed above.
The clamping action of the tool holder is perhaps best understood with reference to
FIGS. 8-11
. With reference to
FIG. 8
, the engagement portion
67
of the clamp
42
can be forced against the tool
28
by causing the clamp
42
to pivot. In the embodiment of
FIG. 8
, the clamp
42
is made to pivot by rotating the cam shaft
74
so as to bring its major axis toward approximate alignment with the cam follower pins
102
,
104
. This is accomplished by moving the handle
82
(manually or otherwise) upward from the position shown in
FIG. 8
to the position shown in FIG.
10
. The cam shaft
74
thus drives the pins
102
,
104
outwardly against the upper portions
66
of the clamps
40
,
42
, thereby causing the lower portions
68
of the clamps to pivot toward the support plate
14
. As the lower portion
68
of the first clamp
42
closes upon the shank
30
of the forming tool
28
, the tool is clamped securely to the holder. It is noted that each clamp
40
,
42
moves independently of the other in this embodiment. Thus, if the second clamp
40
were removed, for example, the first clamp
42
would still operate as described.
As noted above, any desired actuator mechanism can be used as an alternative to the rotating cam shaft
74
described above. For example, an over-the-center plunger-type actuator can alternatively be used to cause a clamp of the invention to pivot. Useful plunger actuators are disclosed in U.S. Pat. No. 6,138,492, the teachings of which are incorporated herein by reference. Here, the plunger actuator is linked to the upper end of an actuator arm that is pivotally attached to a tool holder plate. By extending the plunger actuator, the upper end of the arm is driven away from the holder plate, thereby causing the arm to pivot, and conjointly moving the lower end of the arm toward the holder plate. In much the same manner, a plunger actuator can be linked to the upper portion
66
of a clamp in accordance with the present invention. Those skilled in the art will appreciate that many other mechanical, pneumatic, hydraulic, or electrical actuators can be used as well.
As discussed above, the engagement portion
67
of the clamp
42
can be forced against the tool
28
by causing the clamp
42
to pivot. As is perhaps best understood with reference to
FIG. 9
, this causes the vertical surface
123
(i.e., the first surface of the exterior tool corner) above the safety slot
122
on the tool
28
to bear against the first surface portion
23
of the notch
21
when the clamp
42
is forced against the tool
28
. This in turn causes the lifting shaft
75
to rotate about its axis within the bore
93
(in the clockwise direction as seen in FIG.
9
), thereby bringing the second surface portion
27
of the notch
21
to bear against the downward-facing surface
127
(i.e., the second surface of the exterior tool corner) of the tool
28
. In this manner, the lifting shaft
75
delivers to the tool
28
a mounting force having a component normal to the downward-facing surface
127
of the tool
28
. In the embodiment illustrated in
FIG. 9
, this is an upward component that urges the tool
28
to move in an upward direction. Thus, delivery of mounting force to the tool
28
urges the load-bearing surface
26
of the tool
28
toward the load-bearing surface
24
of the support plate
14
.
The lifting action of the shaft
75
desirably causes enough upward movement of the tool
28
to bring the load-bearing surfaces of the tool and the support plate into engagement. In further detail, the tolerances of the tool holder
10
are preferably such that the load-bearing mounting surface
26
of the tool comes into contact with the load-bearing receiving surface
24
of the support plate
14
just as the contact surface
96
of the clamp
42
engages the confronting surface
123
of the tool
28
. This assures that the tool
28
is securely clamped to the holder and restrained against unintentional movement in both the vertical and horizontal directions. Thus, the forming tool
28
can be secured in an operative position as an adjunct of the clamping action of the tool holder
10
. Accordingly, it is not necessary to force the tip
38
(e.g., the workpiece—deforming surface) of the tool
28
against a forming die
168
on a lower press brake table
226
(as seen in
FIG. 10
) to bring the load-bearing surfaces of the tool and the support plate together (i.e., into engagement with one another).
It is noted that the handle
80
of the tool holder
10
is desirably removably secured in the bore
88
, as is best seen in FIG.
7
. Thus, when the forming tool
28
is in the operative position depicted in
FIGS. 10 and 11
, the handle
80
can be removed from the tool holder
10
by simply pulling the handle
80
upwardly and away from the holder
10
. On the other hand, when the operator desires to remove the tool
28
from the tool holder
10
, the handle
80
is reattached to the holder
10
by inserting the shaft
86
back into the bore
88
. The operator can then move the handle
80
from the position depicted in
FIG. 10
downwardly to the position depicted in
FIG. 8
, the relay releasing the clamping pressure of the clamp
42
on the tool
28
. Once the handle has been thus moved to the unclamped position, the presence of the lip
116
and part of shaft
75
in the safety slot
122
prevents the tool
28
from falling from the holder. As noted above, the tool
28
is retained somewhat loosely between the clamp
42
and the support plate
14
, even in the unclamped position illustrated in
FIGS. 8 and 9
.
At this point, the tool
28
can be horizontally slid from the tool holder
10
unless there is other structure in the way. Preferably, the tool is removed from the holder by manually grasping the tool as shown in FIG.
17
and pulling the lower end of the tool away from the clamp
42
. This movement causes the tool shank
30
to pivot about the bottom edge of the support plate
14
, the upper edge of the tool shank
30
pressing outwardly upon the clamp, which in turn resiliently pivots outwardly to enable the lip
116
and lifting shaft
75
to fully escape the safety slot
122
. The operator advantageously uses both hands to perform this task, so as to reduce the chances of accidentally dropping the tool
28
.
The various manners in which a tool holder of the invention can be mounted to the beam of an upper press brake table would be apparent to those skilled in the art.
FIG. 10
depicts a preferred manner of mounting the tool holder
10
to an upper press brake table. The press brake assembly of
FIG. 10
includes an upper press brake table including the body
12
of the tool holder
10
, and a lower press brake table
226
including a forming die
168
. Shown in cross-section is the longitudinally-extending beam
126
of an upper press brake table. Between the bottom shoulder
128
of the press brake beam
126
, which extends longitudinally, is positioned a wedge
132
having upwardly and downward facing surfaces
134
,
136
, respectfully. The latter surfaces encounter the respective shoulders
128
,
130
. As shown best in
FIG. 7
, the wedge
132
tapers in height from one end
138
to the other
140
, the taper of the wedge compensating precisely for the non-horizontal surface
130
of the support plate
14
such that the bottom surface
24
of the support plate is horizontal and parallel to the upper surface
134
of the wedge
132
. Thus, the distance between the tool's bottom edge
38
(i.e., the workpiece-deforming surface oriented downwardly toward the forming die
168
) and the shoulder
128
of the press brake beam
126
can be adjusted by moving the wedge to the left or right (as seen in FIG.
7
). Once the exact height of the tool edge
38
has been attained, the wedge
132
is locked in place by means of threaded bolts
142
passing through longitudinally-elongated slots
144
formed in the mount plate
16
and thence into threaded holes
196
in the wedge
132
. In this manner, the mount plate
16
and the wedge
132
are held securely together. When the threaded bolts
142
are loosened, the wedge
132
together with the bolts
142
can be moved to the left or right (as seen in
FIG. 7
) to achieve the desired vertical positioning of the tool edge
38
.
The mounting plate
16
can be mounted to the beam
126
of the upper press brake table by means of a generally “C”-shaped clamp
148
. This clamp
148
preferably extends longitudinally along substantially the entire length of the tool holder
10
. The clamp
148
is joined to the beam
126
by means of a threaded screw
150
that passes through the clamp
148
and into the beam
126
. At its lower edge, the clamp
148
includes an inwardly-turned lip
152
having an upwardly-facing shoulder
154
. The lip
152
is received within a longitudinally-extending slot
156
in the outer surface of the mount plate
16
. The slot
156
has a downward-facing shoulder
158
that confronts the shoulder
154
when the tool holder
10
is mounted to the upper table of a press brake.
The tool holder
10
can be readily removed from the beam
126
of a press brake by simply unscrewing the bolts
150
. With reference to
FIG. 11
, it is noted that as the bolts
150
are unscrewed from the beam
126
of the press brake, the clamp
148
is loosened. However, the upward-facing shoulder
154
of the lip
152
remains in contact with the downward-acing shoulder
158
of the slot formed in the mount plate
16
and tends to prevent the tool holder
10
from being dropped unintentionally from the clamp
148
. Once the bolts
150
have been appropriately loosened, the tool holder
10
can be manually grasped, and the lip
152
of the clamp
148
can be removed from the slot
156
, thereby allowing the tool holder
10
to be safety lowered from the beam
126
of the press brake. It is lastly noted that each edge, transition region, interior corner, and the like of the present tool holder is preferably provided with a radius to provide stress relief, as is conventional in the present art.
While preferred embodiments of the present invention have been described, it should be understood that a variety of changes, adaptations, and modifications can be made therein without departing from the spirit of the invention and the scope of the appended claims.
Claims
- 1. A tool holder apparatus for a press brake, the apparatus comprising a support plate having a first receiving surface, and a pivotable clamp having an engagement portion that is moveable toward said first receiving surface by pivoting the clamp, the engagement portion having therein formed a bore in which a lifting shaft is rotatably received, the engagement portion defining an opening communicating with the bore, the shaft having therein formed a notch that is adapted to be engaged through said opening by an exterior corner of a forming tool, the notch being configured such that when the engagement portion of the clamp is forced against such tool a first surface of said exterior corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a second surface of said exterior corner and delivering to the tool a mounting force having a component normal to the second surface of said exterior corner.
- 2. The apparatus of claim 1 wherein the support plate further includes a load-bearing receiving surface forming an exterior corner together with said first receiving surface, the delivery of said mounting force urging a load-bearing mounting surface of the tool toward the load-bearing surface of the support plate.
- 3. The apparatus of claim 2 wherein the load-bearing surface of the support plate is a generally horizontal surface.
- 4. The apparatus of claim 3 wherein the first receiving surface of the support plate is a generally vertical surface.
- 5. The apparatus of claim 3 wherein the load-bearing surface of the support plate is a generally-downward facing surface.
- 6. The apparatus of claim 1 wherein the notch is defined by a single notch surface comprising both said first and second notch surface portions.
- 7. The apparatus of claim 1 wherein the notch is bounded by first and second notch surfaces, the first notch surface comprising said first notch surface portion, the second notch surface comprising said second notch surface portion.
- 8. The apparatus of claim 7 wherein the first and second notch surfaces are separated by an acute notch angle.
- 9. The apparatus of claim 8 wherein said notch angle is between about 45 degrees and about 75 degrees.
- 10. The apparatus of claim 9 wherein said notch angle is about 60 degrees.
- 11. The apparatus of claim 7 wherein the notch further includes a third notch surface joining the first and second notch surfaces.
- 12. The apparatus of claim 1 wherein the lifting shaft is restrained to a limited range of rotation in which at least a portion of the notch is exposed through said opening at all possible orientations of the shaft.
- 13. The apparatus of claim 12 wherein the entire notch is exposed at all possible orientations of the shaft.
- 14. The apparatus of claim 12 wherein the lifting shaft is urged by a spring seated in said bore toward a desired default orientation in which the entire notch is exposed through said opening.
- 15. The apparatus of claim 1 wherein the support plate forms part of a tool holder body to which the clamp is pivotally attached.
- 16. The apparatus of claim 15 wherein the clamp has an upper portion and a lower portion and is attached therebetween to the tool holder body.
- 17. The apparatus of claim 16 wherein the lower portion of the clamp comprises said engagement portion.
- 18. The apparatus of claim 16 wherein the clamp is attached to the tool holder body by a plurality of pins each extending from one of the clamp and the body and terminating in an enlarged head received in a recess defined by the other of the clamp and the body, the enlarged heads and respective recesses being shaped to articulate together when the clamp is made to pivot.
- 19. The apparatus of claim 18 wherein the enlarged heads of the pins are aligned to define an axis about which the clamp is pivoted.
- 20. A tool holder assembly for a press brake, the assembly comprising:a) a support plate having a first receiving surface and a load-bearing receiving surface; b) a forming tool having a first mounting surface on a first side thereof and an exterior corner on a second side thereof, said first mounting surface being engaged with the first receiving surface of the support plate, the tool having a load-bearing mounting surface forming an included right angle with said first mounting surface, said load-bearing mounting surface being adapted to engage the load-bearing surface of the support plate; and c) a pivotable clamp having an engagement portion that is moveable toward said first receiving surface by pivoting the clamp, the engagement portion having therein formed a bore in which a lifting shaft is rotatably received, the engagement portion defining an opening communicating with the bore, the shaft having therein formed a notch that is adapted to be engaged through said opening by said exterior corner of the forming tool, the notch being configured such that when the engagement portion of the clamp is forced against said tool a first surface of said exterior corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a second surface of said exterior corner and delivering to the tool a mounting force having a component normal to the second surface of said exterior corner.
- 21. The assembly of claim 20 wherein said receiving surfaces of the support plate together define an exterior corner, the delivery of said mounting force urging the load-bearing surface of the tool toward the load-bearing surface of the support plate.
- 22. The assembly of claim 20 wherein the load-bearing surface of the support plate is a generally-horizontal, downward-facing surface.
- 23. The assembly of claim 22 wherein the load-bearing surface of the tool is a generally-horizontal, upward-facing surface.
- 24. The assembly of claim 23 wherein said second surface of the exterior corner of the tool is a generally-horizontal, downward-facing surface.
- 25. The assembly of claim 24 wherein the first receiving surface of the support plate and said first surface of the exterior corner of the tool are both generally-vertical surfaces.
- 26. An upper press brake assembly comprising:a) an upper press brake table including a tool holder body; b) a support plate forming part of the tool holder body and having a first receiving surface and a generally downward-facing load-bearing receiving surface, said receiving surfaces together defining an exterior corner; c) a forming tool having a first mounting surface on a first side thereof and an exterior corner defined by first and second corner surfaces on a second side thereof, said second corner surface being generally-downwardly-facing, the first mounting surface of the tool being engaged with the first receiving surface of the support plate, the tool having a load-bearing mounting surface forming an included angle with said first mounting surface and being adapted to engage the generally downward-facing load-bearing receiving surface of the support plate; and d) a clamp attached pivotally to the tool holder body and having an engagement portion that is moveable toward said first receiving surface by pivoting the clamp, said engagement portion having therein formed a bore in which a lifting shaft is rotatably received, the engagement portion defining an opening communicating with the bore, the shaft having therein formed a notch that is adapted to be engaged through said opening by said exterior corner of the tool, the notch being configured such that when the engagement portion of the clamp is forced against the tool said first corner surface bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against said second corner surface and delivering to the tool a mounting force having a generally-upward component.
- 27. A tool holder apparatus for a press brake, the apparatus comprising:a) a support plate having a first receiving surface and a generally downward-facing receiving surface, said receiving surfaces together defining an exterior corner; and b) a pivotable clamp having an engagement portion that is moveable toward said first receiving surface by pivoting the clamp, the engagement portion having therein formed a bore in which a lifting shaft is rotatably carried, the engagement portion defining a slot communicating with the bore, the shaft having therein formed a notch that is adapted to be engaged through said slot by an exterior corner of a forming tool a mounting tang of which is positioned between the first receiving surface of the support plate and the engagement portion of the clamp, the notch being configured such that when the engagement portion of the clamp is forced against such tool a generally-vertical surface of said exterior corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a generally-downward-facing surface of said exterior corner and delivering to the tool a mounting force having a generally-upward component.
- 28. A tool holder apparatus for a press brake, the apparatus comprising a support plate having a first receiving surface, and a clamp having an engagement portion defining a slot communicating with a bore formed therein in which a lifting shaft is rotatably received, the shaft having therein formed a notch that can be engaged through said slot by an exterior corner of a forming tool, the notch being configured such that when it is forced against said exterior corner a first surface of said exterior corner bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against a second surface of said exterior corner and delivering to the tool a mounting force having a component normal to the second surface of said exterior corner.
- 29. A press brake assembly comprising:a) an upper press brake table including a tool holder body; b) a lower press brake table including a forming die; c) a support plate forming part of said tool holder body and having a first receiving surface and a load-bearing receiving surface, said receiving surfaces together forming an exterior corner; d) a forming tool having a first mounting surface on a first side thereof and an exterior corner defined by first and second corner surfaces on a second side thereof, said first mounting surface being engaged with the first receiving surface of the support plate, the tool having a load-bearing mounting surface forming an included angle with said first mounting surface, said load-bearing mounting surface being adapted to engage the load-bearing surface of the support plate, the tool having a workpiece-deforming surface oriented downwardly toward said forming die; and e) a clamp attached pivotally to the tool holder body and having an engagement portion that is moveable toward said first receiving surface by pivoting the clamp, said engagement portion having therein formed a bore in which an elongated shaft is rotatably received, the engagement portion defining an opening communicating with the bore, the shaft having therein formed a notch that is adapted to be engaged through said opening by said exterior corner of the tool, the notch being configured such that when the engagement portion of the clamp is forced against the tool said first corner surface bears against a first surface portion of the notch and causes the shaft to rotate within the bore, thereby bringing a second surface portion of the notch to bear against said second corner surface and delivering to the tool a mounting force having a component normal to said second corner surface; wherein said load-bearing surfaces can be engaged with one another by forcing the engagement portion of the clamp against the tool without forcing the workpiece-deforming surface of the tool against the forming die on the lower table.
US Referenced Citations (16)
Foreign Referenced Citations (4)
Number |
Date |
Country |
0 754 506 |
Jan 1997 |
EP |
0 940 197 |
Apr 1999 |
EP |
08186135 |
Feb 1998 |
JP |
11174220 |
Jan 2001 |
JP |