Metal founding – Means to shape metallic material – Pressure shaping means
Reexamination Certificate
2000-10-27
2002-04-23
Elve, M. Alexandra (Department: 1725)
Metal founding
Means to shape metallic material
Pressure shaping means
C164S121000, C164S341000, C425S168000, C425S183000
Reexamination Certificate
active
06374900
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to die-casting machines and, more particularly to a die holder assembly having an upper mould holder with a clamp ring and a body segment.
BACKGROUND OF THE INVENTION
As is well known, die-castings are produced by forcing a molten metal under pressure into one or more die cavities that are machined into a die set or into cavities that are machined, die-cut or otherwise formed in a part. For example, one exemplary part is a rotor for an electric machine. The rotor typically includes a stack of laminations that are die cut from a lamination material. The rotor laminations include rotor bar bores into which aluminum is die cast. Oftentimes, end rings are die cast on opposite ends of the stack of laminations.
A die-casting machine typically includes an upper mould and a lower mould. The die-casting machine also includes an injection system for delivering molten material, such as aluminum into the die cavity and an ejector system for ejecting the casting from the die cavity. As is conventional in horizontal die-casting machines, the lower mould is secured to the stationary cover platen while the upper mould is secured to the moveable ejector platen. The shot of molten metal is typically injected into the cavity in the part through the lower mould. Ejector pins that are associated with the ejector system extend through access holes that are formed in the upper mould. The ejector platen is mounted to a power-operated ram that is actuated to open and close the upper and lower moulds.
In order to reduce the time that is required for die changes, it is known to preassemble the die set into a die holder assembly that includes upper and lower mould holders. The upper mould holder is mounted to the ram and the lower mould holder is mounted to the stationary cover platen. To permit utilization of the die holder assembly with most die-casting machines, the upper and lower mould holders include access bores to accommodate such things as leader pins, ejector pins, and clamps for mounting the die set thereto.
An exemplary die-casting machine according to the prior art is illustrated in FIG.
1
A and is generally designated
10
. The die-casting machine
10
includes a frame
12
with a pair of left-side tie bars
14
and a pair of right-side tie bars
16
. Upper and lower platens
20
and
22
extend between the tie bars
14
and
16
. An upper ram
26
is connected to an upper ram adapter
28
that defines a mounting chamber
30
in a downwardly-facing direction. Horizontal clamp cylinders
32
and
36
extend inwardly into the mounting chamber
30
. The horizontal clamp cylinders
32
and
36
reciprocally move clamp wedges
38
and
40
inwardly and outwardly in a horizontal direction. The clamp wedges
38
and
40
in conjunction with the clamp cylinders
32
and
36
releasably engage an upper mould holder
50
.
The upper mould holder
50
defines an annular recess
54
on an outer surface thereof that engages the clamp wedges
38
and
40
. A bottom portion
56
of the upper mould holder
50
is removably attached to upper moulds
60
and
62
that include downwardly-facing pilot projections
64
. A lower mould holder
74
includes sleeves
76
and
78
for receiving the leader pins
70
and
66
, respectively. A top portion
80
of the lower mould holder
74
is removably attached to lower moulds
82
and
84
. The lower moulds
82
and
84
include upwardly-facing pilot projections
86
. A shot ram
88
is connected to the lower mould holder
74
.
Referring now to
FIGS. 1A
,
1
B, and
1
C, the projections
64
of the upper moulds
60
and
62
and the projections
86
of the lower moulds
82
and
84
are received by a rotor shaft bore
90
that is formed by a stack of interconnected rotor laminations
91
. The rotor laminations
91
typically have a circular cross-section and include rotor bar bores
92
that are located adjacent a radially outer surface
93
thereof. The rotor bar bores
92
of the adjacent laminations
91
are offset or skewed at a skew angle
94
that is typically between 2 to 10 degrees. In other words, a first rotor is rotated at the skew angle relative to the adjacent rotor laminations
91
. The rotor laminations
91
also include interconnects
95
that are typically formed by making die cuts that are deformed using a punch. The deformed punched portion of the die cuts in one lamination
91
is received by the die cut of an adjacent lamination
91
. The interconnects
95
hold the rotor laminations
91
together during assembly. The upper and lower moulds
60
,
62
,
82
, and
84
typically define end ring cavities (not shown) that are located adjacent opposite ends of the stack of rotor laminations
91
. The molten aluminum enters the end ring cavities to create end rings
96
.
When the injector pins inject molten metal such as aluminum into the rotor bar bores
92
-
1
, the molten metal moves under pressure into one of the end ring cavities. Then, the molten metal moves under pressure back through the rotor bar bores
92
-
2
and into the other end ring cavity
96
-
2
.
When the upper mould holder
50
is to be changed and/or worked on, the upper mould holder
50
is typically lowered onto the lower mould holder
74
or any other suitable support. The clamp cylinders
32
and
36
are fully retracted to move the clamp wedges
38
and
40
out of the annular recess
54
. The upper ram
26
is moved upwardly to allow access to the upper mould holder
50
. In other words, the upper mould holder
50
is released from the upper ram
26
and the upper ram adapter
28
. Work is completed on the upper mould holder
50
or a different upper mould holder
50
is installed. The process is reversed to reattach the upper mould holder
50
.
Oftentimes when the technicians attempt to reattach the upper mould holder
50
to the upper ram adapter
28
, the technicians fail to retract the clamp cylinders
32
and
36
. This is due, in part, to the visually obstructed position of the clamp wedges
38
and
40
that are located in the mounting chamber
30
of the upper ram adapter
28
. When the technicians lower the upper ram
26
and the upper ram adapter
28
over the upper mould holder
50
, the clamp wedges
38
and
40
damage a radially outer edge
92
of an upper surface
94
of the upper mould holder
50
. The damage to the upper mould holder
50
can, in some cases, be repaired. The repairs, however, can be expensive. Even if the upper mould holder
50
can be repaired, subsequent accidents permanently damage the upper mould holder
50
requiring replacement.
SUMMARY OF THE INVENTION
A die-casting assembly according to the invention includes a ram and a ram adapter that is connected to the ram. The die-casting assembly further includes a mould holder and a mould that is connected to the mould holder. An attachment device includes a clamp cylinder having an end that removably connects the mould holder to the ram adapter. The mould holder includes a clamp ring that defines a radially projecting engagement flange. The upper mould holder includes a body segment having an upper surface that is removably connected to the clamp ring in a plurality of angular positions. When the clamp ring is damaged during use, the clamp ring can be rotated a plurality of times relative to the body segment without requiring repair or replacement of the upper mould holder.
In other features of the invention, the clamp ring is annular and includes a first plurality of axial bores that provide access to leader pins that are connected to the body segment. The access bores allow the leader pins to be adjusted, removed or replaced without removing the clamp ring. The clamp ring includes a second plurality of bores arranged in a first pattern for receiving bolts that connect the clamp ring to the body segment. The body segment includes a third plurality of bores arranged in a second pattern for receiving the bolts that connect the clamp ring to the body segment. The first and second patterns are positioned and arranged to allow the clamp ring to be ro
Elve M. Alexandra
Harness & Dickey & Pierce P.L.C.
Tran Len
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