Presses – Reciprocating press construction – Range of movement adjustment
Reexamination Certificate
1999-06-15
2001-06-19
Lazarus, Ira S. (Department: 3721)
Presses
Reciprocating press construction
Range of movement adjustment
C100S282000, C072S450000
Reexamination Certificate
active
06247399
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a press machine in which a slide is driven from its downside so as to move in the up and down direction.
2. Prior Art
As one of press machines, there is an underdrive press machine such as a dieing press machine, of which the slide is driven from the downside through a link mechanism associated with the driving means. This press machine is constructed such that the rotary motion of a crankshaft rotated by a driving source is once converted into a reciprocating motion with the help of a link mechanism such as a knuckle joint, a toggle joint and so forth, whereby a slide is correspondingly reciprocated by the converted motion in the up and down directions over the link mechanism.
In the prior press machines of this kind, however, the stroke of a slide motion in the up and down directions is limited to a preset value determined according to the sorts of press processings such as the precise press processing (low speed press processing), the stamping processing (high speed press processing) and so on.
Consequently, in the prior art press machine of this kind, the stroke of the slide can not be changed, so that the applicable range of the press machine has been limited by such limited stroke of the slide.
Therefore, in the press machine of this kind, it is important that the stroke of its slide motion in the up and down directions be made variable.
SUMMARY OF THE INVENTION
According to the invention, there is provided a press machine which includes a frame; a plurality of posts movably extending in the up and down directions; an upper slide fitted to the upper end portions of the posts; a lower slide fitted to the lower end portions of the posts; a crankshaft rotated by a driving source; a link mechanism having first and second levers connected with each other so as to perform bending and stretching motions so that the lower slide may move vertically, one of the levers having a first fulcrum connected with the frame, the first fulcrum being not moved by the bending-stretching motion, and the other lever having a second fulcrum connected with the lower slide, the second fulcrum being moved by the bending-stretching motion; a connecting mechanism for connecting the crankshaft with the link mechanism such that the first and second levers are bent and stretched as the crankshaft is rotated; and an adjusting device for connecting with the link mechanism or the connecting mechanism so as to adjust the range of the bent angle made by the first and second levers.
The first and second levers are bent and stretched by the connecting mechanism as the crankshaft is rotated. As the first and second levers are bent and stretched, this bending-stretching motion of the first and second levers is transmitted to the lower slide, and a plurality of posts come to be reciprocated in the up and down directions along with the reciprocating motion of the lower slide. Thus, the upper slide to which the die is attached comes to be reciprocated in the up and down directions above the lower slide.
As the bent angle (the range of bending-stretching angle) is changed by the adjusting device, the interval between the first and second fulcrums of the link mechanism is correspondingly changed, and thus, the range of the up and down motion of the lower slide and posts are changed in correspondence therewith. As a result, the stroke of the up and down motion of the upper slide is varied.
As described above, in the press machine of the type wherein the slide is driven from its lower side, if there is provided such an adjusting device as can adjust the range of the bending-stretching angle of the first and second levers, the stroke of the up and down motion of the upper slide can be made variable in compliance with the sort of press processing.
The adjusting device may be provided with a circular plate-shaped rotating body rotatable about an axis extending in one direction, the rotating body having a threaded hole; a rotating mechanism for rotating the rotating body; and a moving body having a male screw portion mating with the threaded hole and connected with the link mechanism or the connecting mechanism. With the adjusting device constituted as above, as the position of the moving body in one direction can be finely adjusted, it becomes possible to finely adjust the stroke of the up and down motion of the upper slide.
However, the adjusting device may be constituted to include a rotating body pivotally connected with the link mechanism or the connecting mechanism, a pivotal joint to the link mechanism or the connecting mechanism being movable about an axis extending in one direction, and a rotating mechanism for rotating the rotating body. With the adjusting device constituted as such, the pivotal joint is displaced as the rotating body is rotated with the rotating mechanism, thus enabling the stroke of the up and down motion of the upper slide to be finely adjusted.
The connecting mechanism can be provided with third and fourth levers connected with each other so as to be bent and stretched, one of the levers being connected with the adjusting device; a connecting rod for connecting the eccentric shaft portion of the crankshaft with the other of the third and fourth levers such that the third and fourth levers are correspondingly bent and stretched as the crankshaft is rotated; and fifth lever connecting the third and fourth levers with the link mechanism such that the first and second levers are correspondingly bent and stretched as the third and fourth levers are bent and stretched. With the connecting mechanism as constituted as above, when the position of the joint between one of the third and fourth levers and the adjusting device is changed relative to the frame by the adjusting device, the range of the bending-stretching angle of the first and second levers is changed, whereby the stroke of the up and down motion of the upper slide is changed correspondingly.
The connecting mechanism may further include a slider arranged on the frame such that it can move in a reciprocating fashion and is connected with the joint between the connecting rod and the other of the third and fourth levers. As the slider serves to limit the moving direction of the joint between the connecting rod and the other lever of the third and fourth levers, thereby allowing the link mechanism to exactly bend and stretch.
The adjusting device may include a rotating body pivotally connected with the link mechanism or the connecting mechanism, and a rotating mechanism for rotating the rotating body. The connecting mechanism may include third and fourth levers connected with each other so as to be bent and stretched, at least one of the levers being pivotally connected with the rotating body; a connecting rod for connecting the eccentric shaft portion of the crankshaft with the other of the third and fourth levers such that the third and fourth levers are correspondingly bent and stretched as the crankshaft is rotated; and fifth lever connecting the third and fourth levers with the link mechanism such that the first and second levers are correspondingly bent and stretched as the third and fourth levers are bent and stretched; wherein the rotation center of the rotating body is located at the joint center of the third and fourth levers or at a point in the vicinity of or apart from the joint center.
In such a situation as the rotating body is connected with the joint between the third and fourth levers or with a point in the vicinity thereof and the slide is set on the position of the lower dead point, if the rotating body is angularly rotated by the driving mechanism, the rotating body is angularly rotated about the joint between the third and fourth levers or about a point in the vicinity thereof, thereby changing the bent angle (the range of bending-stretching angle). With this, the swinging position and swinging angle of the third and fourth levers are changed as they are bent and stretched in correspondence with the rotation of the crankshaft. However,
Huynh Louis K.
Ipsolon LLP
K.K. Yamada Dobby
Lazarus Ira S.
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