Turning – Process of turning
Reexamination Certificate
2000-06-07
2003-09-30
Tsai, Henry W. H. (Department: 2183)
Turning
Process of turning
C082S129000, C082S118000
Reexamination Certificate
active
06626072
ABSTRACT:
TECHNICAL FIELD
This invention relates to multiple spindle machines, and particularly to multiple spindle machines having plural machining capability.
BACKGROUND ART
Multiple spindle machines are known in the prior art. Multiple spindle machines are used to mass produce standardized types of components. Multiple spindle machines typically have several workstations at which machining operations are performed. A piece of raw stock, such as bar stock, enters the machine at a first station and as the machine indexes, various machining operations are performed. Once a station is indexed completely through the machine a completed a part is formed. The part is released and the process is repeated for that station with a new piece of raw stock. The advantage of multiple spindle machines is that all stations in the machine are producing parts simultaneously, resulting in high production.
Multiple spindle machines typically have a large indexing drum with four, six or eight stations thereon. Each of the stations carries a work piece. In all but one of the stations, where a new piece of stock enters, a machining operation is performed. After each operation is completed the drum is rotated so that each work space moves sequentially through the location where the various operation is performed. Machining operations typically performed at a multiple spindle machine include turning and threading.
Most multiple spindle machines are very efficient in terms of producing standardized parts at a high rate. However, one draw back associated with multiple spindle machines is that the entire machine often operates off of a single main motor. The main motor simultaneously drives all the devices in the machine.
The speed of the multiple spindle machine typically changes from high speed to low speed and back again during the course of the operating cycle. High speed is typically used for times in the machine cycle where critical machining operations are not occurring. High speed operation is desirable when the machines are indexing or when the tools are moving to or away from the work pieces that are not performing work thereon. Low speed operation is used when the tools in the machine are forming the metal. As stated, the machining operation of the bar stock is performed utilizing a threading die which is driven via a worm gear. In typical multiple spindle machines a worm gear is driven through a threading clutch. The threading clutch acts to translate rotation from a reversible shaft to the threading shaft.
As previously described a typical prior art multiple spindle machine includes a main drive motor which operates all of the components on the multiple spindle machine that perform machining operations on the work pieces through a transmission.
The transmission includes various components including a high speed clutch and a low speed clutch. A rear view of a typical multiple spindle machine set up for a dual threading operation is shown in FIG.
1
and has a high speed clutch
12
and a low speed clutch
14
.
FIG. 2
is a side view of the multiple spindle machine shown in FIG.
1
.
A high speed clutch shaft
11
extends along a longitudinal direction in operative connection with a main motor (not shown) of the multiple spindle machine and may be rotated in either a first or second direction to drive high speed clutch
12
in either the first or second direction. A low speed clutch shaft
13
extends along a longitudinal direction in operative connection with the main motor and may be rotated in either a first or second direction to drive low speed clutch
14
in either the first or second direction.
Work pieces formed in the multiple spindle machine are carried on six stations
20
located on a main spindle carrying drum (not shown), two of the six stations
20
being utilized for threading operations in this set up, which will be described below without reference to the other machining operations.
The high and low speed clutches are selectively actuated to drive through a gear train
15
first shaft
16
and second shaft
36
at either a high or a low speed. High speed is used when machining operations are not occurring, such as when the machine is indexing or when the tools are moving to or away from the work pieces. Low speed operation is used when the tools in the machine are machining the work piece.
Stations consist of rotatable spindles through which work piece stock, such as bar stock, extends. Raw stock enters the machine at a first position then indexes through each of the other five stations so that a completed part is produced and cut off before the drum returns to the first position.
A station
20
is schematically shown holding a work piece
22
in FIG.
3
. Similarly a second station
20
holds a second work piece
23
as shown in FIG.
3
A. The work pieces are held in collets in the spindle and rotate in the direction of the arrow as shown. When the low speed clutch
14
is engaged, the output shafts
16
,
36
will rotate in the same direction as the work pieces. The high speed clutch
12
is engaged once the threads-have been formed. The threading tool is then backed off the work piece.
The threading process for the first threading tool is illustrated schematically in
FIGS. 3-4
. A first threading tool
24
is guided on a first slide
26
. A switch actuator
30
is attached to the threading tool
24
. The first threading tool is shown in the fully retracted position shown in FIG.
3
. The switch actuator engages a limit switch
32
so as to indicate that the first threading tool is in the fully retracted position. As the multiple spindle machine cycles, first threading tool
24
is moved to engage first work piece
22
by movement on first slide
26
using an actuator such as first pneumatic cylinder
28
. The threading tool moves to engage the work piece until the limit switch
32
is moved to the fully forward, full stroke position by the switch actuator
30
as shown in FIG.
4
.
The threading process for the second threading tool is illustrated schematically in
FIGS. 3A-4A
. A second threading tool
40
is guided on a second slide
42
. As the multiple spindle machine cycles, second threading tool
40
is moved to engage second work piece
23
by movement on second slide
42
using an actuator such as a second pneumatic cylinder
44
. The second threading tool moves to engage the second work piece until limit switch
32
has moved to the fully forward, full stroke position of first threading tool
24
by the switch actuator
30
as shown in FIG.
4
.
When first threading tool
24
has been moved to the fully forward position as shown in
FIG. 4
, the actuator
30
changes direction in response to control signals to return the first and second threading tools to their original positions. The switch actuator
30
engages the limit switch
32
to indicate that the first threading tool
24
is again in the fully retracted position as shown in
FIG. 5
, the threading operation is complete and the threading tools are sufficiently disposed from the work pieces and spindle so that the main drum may index.
The second threading tool
40
does not have a switch actuator to engage a limit switch so as to indicate that the second threading tool is in either the fully forward or the fully retracted position. The multiple spindle machine is set up based on both threading operations being completed simultaneously. Use of a second limit switch and switch actuator combination would be redundant when the machine operates correctly. Also, unintended operation could occur if a second actuator and switch combination sent a completion signal rather than the first. A flow diagram of the threading operation is shown in FIG.
6
.
All of the stations rotate the work pieces in the same direction and all of the machining operations occur generally simultaneously. There are several problems associated with the design and operation of the prior art multiple spindle machines in which threading simultaneously at a plurality of stations has been attempted. Threading operations must be started and finished g
Kalinsky Robert M.
Stevens Scott W.
Jocke Ralph E.
Logan Clutch Corporation
Tsai Henry W. H.
Walker & Jocke
Wasil Daniel D.
LandOfFree
Multiple spindle machine plural threading apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multiple spindle machine plural threading apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multiple spindle machine plural threading apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3083983