Presses – Reciprocating press construction – Range of movement adjustment
Reexamination Certificate
2002-05-16
2003-06-10
Ostrager, Allen (Department: 3725)
Presses
Reciprocating press construction
Range of movement adjustment
C100S271000
Reexamination Certificate
active
06575087
ABSTRACT:
Japanese patent application no. 2001-147243 filed on May 17, 2001 is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
The present invention relates to a press machine in which a drive mechanism and a slider are interconnected through a suspension mechanism.
FIG. 5
shows a press machine
1
P in which a drive mechanism (e.g., crank mechanism
10
) and a slider
5
are interconnected through a suspension mechanism
20
P.
Referring to
FIG. 5
, the press machine
1
P also comprises a crown
2
, columns
3
and a bed
7
. On the bed
7
is placed guides
8
each for slidably guiding a guide rod
6
connected to the slider
5
.
The suspension mechanism
20
P comprises a connecting rod
21
connected to a crank shaft
11
, the top end of which forms the drive mechanism
10
, a male screw member
23
P rotatably connected to the bottom end of the connecting rod
21
through a pin
22
, a female screw member
37
P screwed over the male screw member
23
P to form a slider positioning device
30
P together with the male screw member
23
P and a retainer
25
P having a top end located within the cylindrical bottom of female screw member
37
P and a bottom end integrally connected with the slider
5
, the retainer also including a mounting member
26
P integrally formed therewith.
The slider positioning device
30
P comprises a motor
31
P, a rotational-power transmission mechanism
32
P including various gear wheels, a worm shaft and a worm wheel
35
P. The worm wheel
35
P is fixedly connected with the female screw member
37
P through a key
36
P for synchronous rotation.
As the motor
31
P is rotatably started, the female screw member
37
P may be rotated relative to the fixed male screw member
23
P and moved up and down along the axis Z thereof. Thus, the vertical position of the slider
5
carried on the female screw member
37
P may be regulated. Such a screw structure (or connection) is lubricated by oil which is gravity-supplied onto the periphery of the male screw member
23
P through a longitudinal oil groove
23
MZ formed thereon. After being lubricated, the oil is collected at the bottom end of the oil groove
23
MZ for re-circulation.
When the drive mechanism
10
is started after the slider has been positioned, the connecting rod
21
is swingably moved to repeatedly move the male screw member
23
P, female screw member
37
P and retainer
25
P (
26
P) up and down. Thus, the slider
5
may repeatedly be moved between the top and bottom dead centers.
The entire press machine including the suspension mechanism
20
P and slider positioning device
30
P is structured by combining (or assembling) a great number of components. The manufacturing precision for each component is limited due to various conditions (e.g., cost, technology and load capacity). Depending on the assembling operation, it is also limited to some degree to micrify a clearance for reducing a frictional resistance to provide a smooth action. On the other hand, there may be created a clearance larger than the above-mentioned limitation between adjacent components after they have been assembled.
On the contrary, there may be frequently a case that a relatively large clearance must positively be formed between adjacent components to eliminate any influence from possible heat shrinkage and deformation.
In any case, the presence of relatively large clearance between adjacent components degrades the mechanical precision in the press machine, reduce the precision (or quality) in the pressed products and produce vibration and noise during the pressing operation.
Furthermore, the power transmission capacity may be reduced by creating a power (load) imbalance from any spacing between adjacent components (e.g., between contacting faces or between pressure receiving faces). Additionally, the system in which the slider positioning device
30
P is incorporated into the suspension mechanism
20
P requires a complicated lubricating/cooling mechanism for the screw parts (
23
P and
37
P) which form part of the slider positioning device
30
P. This also causes contamination of the press machine due to the flow of lubricating (or cooling) oil drops.
Depending on the size of the clearance in the slider positioning device
30
P (
23
P and
37
P), the engagement between the screw parts (
23
P and
37
P) maybe loosened during the pressing operation. In addition, the position (or die height) of the slider
5
may be changed to increase defectives and to degrade the yield.
BRIEF SUMMARY OF THE INVENTION
The present invention may provide a press machine which may improve the mechanical precision and product precision (or quality) and greatly reduce vibration and noise by eliminating any backlash in the pressing power transmission.
In the press machine according to the present invention, the time period between the state in which the press stops and the other state in which a press load is produced after the press has been started is referred to as the “non-press load producing time”. In the non-press load producing time, a first pressure layer is formed by charging a pressurized fluid into a first clearance between a first face, facing downward for example, (e.g., male screw member) of a first component selected from a plurality of components forming a suspension mechanism and a third face, facing upward for example, (e.g., female screw member) of a second component opposing the first face. Thus, a vertical clearance (or backlash) which is formed between the first and third faces apparently disappears. At the same time, the first and third faces are mechanically brought into direct contact with each other through the pressurized fluid.
At the same time, a second face (e.g., upward face) of the first component which is dynamically opposing the first face thereof is pressed against a fourth face (e.g., downward face) of the second component which is opposing to the second face, for example, under the action of an upward lifting force. Thus, a second clearance between the second and fourth faces disappears. Moreover, the second and fourth faces are brought into direct contact with each other so that no clearance (backlash) is formed therebetween.
Namely, a mechanical power-transmission connection is formed between the first component (e.g., male screw member) and the second component (e.g., female screw member) without backlash (or clearance). Thus, vibration and noise may greatly be reduced during a press startup process between a press start at which slider starts to move downward and a time whereat the press load start to be produced.
In a press load producing time in which the slider further moves downward to start the pressing operation and to continue the pressing operation, the upward drag force (or press load) from the second component (e.g., female screw member) increases. Thus, the internal pressure in the first pressure layer increases with the downward movement of the first component (e.g., male screw member) in the drive mechanism. Thus, a second pressure layer maybe formed and maintained in the second clearance between the second face (e.g., upward face) of the first component and the fourth face (e.g., downward face) of the second component using the pressure of the pressurized fluid increased when the press load exceeds the internal pressure of the first pressure layer. In other words, the second pressure layer is increased and maintained during the press load. Finally, the pressure in the second pressure layer is formed to be the same as the formed pressure of the first pressure layer in the non-press load producing time.
In other words, the second pressure layer is inversely formed while the thickness of the first pressure layer decreases. The thickness of the second pressure layer also increases. In such a process, vibration and noise may greatly be reduced.
As the first pressure layer subsequently disappears, the first and third faces are brought into direct contact with each other. Thus, the pressing power may be transmitted directly from the first component to the second component. In oth
Shiga Masakatsu
Shimizu Noriyuki
Taniguchi Naonori
Aida Engineering Ltd.
Nguyen Jimmy T
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ostrager Allen
LandOfFree
Press machine having suspension mechanism does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Press machine having suspension mechanism, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Press machine having suspension mechanism will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3144327