Abstract:
A slide drive device for a press changes a slide stroke without a changing either a top or bottom dead center position of a slide. The slide drive device allows stroke adjustment without a loss of left-right balance in the slide drive device. An adjusting mechanism is driven by an eccentric part and a crank shaft. The adjusting mechanism is adaptable to fix either the top or bottom dead center position. A linear guide mechanism, is driven by the adjusting mechanism, and transfers adjustments in slope angle into changes in stroke relative to either the top or bottom dead center position without requiring a change in the dead center position. Alternate embodiments allow positioning and adjustment for convenience and economy.

Description:
BACKGROUND OF THE PRESENT INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a slide drive device for a press. The slide drive device provides a stroke adjusting function in which a dead center position is fixed and a slide strike is adjustable. The dead center position may be either a top or bottom dead center position.  
           [0003]    2. Description of the Related Art  
           [0004]    Japanese Laid Open Patent Publication Numbers 7-132400,11-77398, and 11-197888 are examples of slide drive devices for presses that use links equipped with a stroke adjusting function.  
           [0005]    In Japanese Laid-Open Patent Publication Number 7-132400, the slide stroke can be changed with an adjustment at one position. Making a stroke correction is difficult in this device since the adjustment position is at a branching point for a left and right drive. When the stroke is changed, the bottom dead center position also changes. When the stroke is lengthened, mechanical acceleration at the top dead center is greatly increased.  
           [0006]    In Japanese Laid-Open Patent Publication Number 11-77398, the left and right slides have separate slide stroke adjustment mechanism. Each mechanism must be adjusted separately. During use, there is a loss of precision due to operational backlash. During adjustment, each slide must be adjusted individually. Since each mechanism is separate there may be a loss of left-right balance. Further, although the bottom dead center position does not change with the change in the stroke, the pitch between the points cannot be narrowed by the adjusting mechanism disclosed.  
           [0007]    As in the previous device, in Japanese Laid-Open Patent Publication Number 11-197888, a slide stroke is similarly adjusted between separate left and right slides. When the precision of the adjustment mechanism deteriorates, there is the possibility of a breakdown of balance between the left and right side.  
         OBJECT AND SUMMARY OF THE PRESENT INVENTION  
         [0008]    It is an object of the present invention to provide a slide drive device for a press machine.  
           [0009]    It is another object of the present invention to provide a slide drive device for a press where either a bottom or a top dead position does not change during slide stroke adjustment.  
           [0010]    It is another object of the present invention to provide a slide drive device for a press machine where there is no loss of left-right balance during slide stroke adjustment.  
           [0011]    It is another object of the present invention to provide a slide drive device where an adjusting function occurs before a left-right drive branching.  
           [0012]    It is another object of the present invention to provide a slide drive device where a top or bottom dead center position can be changed smoothly with high precision.  
           [0013]    It is another object of the present invention to provide a slide drive device with a guide board that can be pivoted to a specified angle and change a slope of a connecting rod without changing a top or bottom dead center position.  
           [0014]    It is another object of the present invention to provide a slide drive device where the adjustment of a slide stroke does not directly effect the precision of the press.  
           [0015]    It is another object of the present invention to provide a slide drive device where the motion of a connecting rod can be converted with high precision to a reciprocating motion along a linear trajectory.  
           [0016]    It is another object of the present invention to provide a slide drive device where the motion of a connecting rod can be converted with high precision to a reciprocating motion along an arc-shaped trajectory through a trajectory forming link.  
           [0017]    It is another object of the present invention to provide a slide drive device where the slope of an arc-shaped trajectory can be change by pivoting a guide board a specified angle.  
           [0018]    It is another object of the present invention to provide a slide drive device where the top or bottom dead center position of the small end of a connecting rod remains the same while a top or bottom dead center position can be changed smoothly.  
           [0019]    It is another object of the present invention to provide a slide drive device where a pin, connecting a connecting link with a drive branching link, has a reciprocating motion along a vertical line and maintains a left-right balance with high precision.  
           [0020]    It is another object of the present invention to provide a slide drive device where a drive branching link reciprocates substantially linearly and maintains a left-right balance with a low number of parts and simple mechanism.  
           [0021]    Briefly state, the present invention relates to slide drive device for a press which allows a change in slide stroke without a change in a top or bottom dead center position of a slide. The slide drive device also allows stroke adjustment without a loss of left-right balance in the slide drive device. An adjusting mechanism is driven by an eccentric part of a crank shaft. The adjusting mechanism is adaptable to fix either the top or bottom dead center position on customer demand. A linear guide mechanism, driven by the adjusting mechanism, transfers adjustments in slope angle into changes in slide stroke relative to either the top or bottom dead center position without requiring a change in the dead center position. Alternate embodiments allow positioning and adjustment for convenience and economy.  
           [0022]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, comprising: means for adjusting the slide drive device, the adjusting means being effective to adjust a stroke of the slide, the adjusting means being pivotable about a center position to adjust the stroke, the center position being one of a top and a bottom dead center position of the slide, the adjusting means receiving a reciprocating motion, means for guiding the slide drive device, a connecting link, the connecting link operably transferring the reciprocating motion to the guiding means, the guiding means being effective to convert the reciprocating motion to a guiding displacement, at least one drive branching link in the guiding means, at least one of a first and a second upper toggle means, the one upper toggle means being effective to transfer the guiding displacement to the slide and drive the slide through a cycle, and the at least one drive branching link being effective to transfer the guiding displacement to the one upper toggle means whereby the slide operates in the cycle.  
           [0023]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: a connecting rod, the connecting rod slidably affixed to the adjusting means, a crank shaft; an eccentric part on the crank shaft, the eccentric part having an reciprocating motion, the connecting rod connects the eccentric part to the adjusting means, and the connecting rod operably transfers the reciprocating motion to the adjusting means where by the slide operates through the cycle.  
           [0024]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide wherein: the center position is one of a top and a bottom dead center position of the slide, the adjustment means is slidably affixed to the connecting rod, the adjusting means is operable to guide the connecting rod along a specified trajectory, and the adjusting means is pivotable about the center position to adjust the specified trajectory.  
           [0025]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: the first and the second upper toggle means, a rotation center on each the first and second upper toggle means, the rotation center permitting the first and second upper toggle means to rotate in an arc, a first link connects each the rotation center to the at least one drive branching link, the at least one drive branching link effective to transfer the guiding displacement to each the first and second upper toggle link means, a first and a second lower toggle link, a second link operably connects each the rotation center to each the respective lower toggle link, and the first and second upper toggle means operably transfer the guiding displacement through the second links to respective first and second lower toggle links and the slide whereby the slide operates through the cycle while maintaining a left and right balance.  
           [0026]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: a guide board in the adjusting means, a groove in the guide board, a slider being slidable in the groove, a pin extending from the slider, the groove and the pin being pivotable about the center position, one end of a first and second end of the connecting rod, the one end operable about the pin, and the slider and the pin being effective to transfer the reciprocating motion to the connecting link and the guiding means.  
           [0027]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: a base in the guiding means, a groove in the base, the groove being along a centerline between the upper toggle means, a slider being slidable in the groove, the connecting link operably connected to the slider, the connecting link transferring the reciprocating motion to the slider whereby the slider operates along the centerline, the at least one drive branching link operably connected to the slider, and the at least one drive branching link and the slider transferring the guiding displacement to the first and second upper toggle means whereby the slide operates through the cycle while maintaining a left and right balance along the centerline.  
           [0028]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising, a trajectory pin, a trajectory forming link, the trajectory pin in the adjusting means, the trajectory pin opposite the center position on the guide board, the trajectory forming link operably connecting the trajectory pin to the first end of the connecting rod, the trajectory pin, the trajectory forming link, and the adjusting means effective to convert the reciprocating motion of the first end to an arc-shaped trajectory.  
           [0029]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, wherein: the adjusting means is operable at a position equidistant between the first and second upper toggle means, the crank shaft and the eccentric part is below the adjusting means, and the guide means is above the adjusting means opposite the crank shaft.  
           [0030]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: a first and second dynamic balancer, a first and second retention link, the first and second retention links on the first and second upper toggle means, the first and second dynamic balancers operably connected to each respective the first and second retention links through the retention links, the first and second dynamic balancers having a shape and a weight adaptable to each respective the first and second upper toggle link and the slide, and the first and second balancers at positions to minimize vibrations when the first and second upper toggle links drive the slide in the cycle.  
           [0031]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: a first pin in each the first and second upper toggle means, the first links connects the first pins to each respective the rotation center on each the first and second upper toggle means, the at least one drive branching link operably connecting the first and second upper toggle means at the first pins on a common inner tangent line to each the arc.  
           [0032]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: a first, second, and third element on the drive branching link, a the second element between the first and second elements, the second element being a central support pin, the first and third elements being on each respective the first support pin, and the connecting link operably connecting to the drive branching link at one of the first, second, and third elements.  
           [0033]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: a first and second dynamic balancer, a first and second retention link, the first and second retention links on the second links of each first and second upper toggle means, the first and second dynamic balancers operably connected to each respective the first and second retention links through the retention links, the first and second dynamic balancers having a shape and a weight adaptable to each respective the first and second upper toggle link and the slide, and the first and second balancers at positions to minimize vibrations when the first and second upper toggle links drive the slide in the cycle.  
           [0034]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: the connecting link operably connects to the drive branching link at the second element, and the drive shaft and the adjusting means are above the first and second upper toggle means and the drive branching link.  
           [0035]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: the connecting link operably connects to the drive branching link at one of the first and third elements, and the drive shaft and the adjusting means are below the first and second upper toggle means and the drive branching link.  
           [0036]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: the connecting link operably connects to the drive branching link at one of the first and third elements, the drive shaft is below the first and second upper toggle means, the adjusting means is above the first and second upper toggle means opposite the drive shaft, and the guiding means is between the drive shaft and the adjusting means.  
           [0037]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: the connecting link operably connects to the drive branching link at one of the first and third elements, the drive shaft above the first and second upper toggle means, the adjusting means below the first and second upper toggle means opposite the drive shaft, and the guiding means is between the drive shaft and the adjusting means.  
           [0038]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, further comprising: a first end and second end element on the drive branching link, the first end element at a first end of the drive branching link, the second end element on the drive branching link, and the connecting link operably connecting to the drive branching link between the first end element and the second end element.  
           [0039]    According to an embodiment of the present invention, there is provided, a slide drive device for a press machine having a slide, comprising: a connecting rod, means for adjusting the slide drive device, the adjusting means being effective to adjust a stroke of the slide, the adjusting means slidably affixed to the connecting rod, the connecting rod being effective to transfer a reciprocating motion to the adjusting means, the adjusting means being operable to guide the reciprocating motion along a specified trajectory, the adjusting means being pivotable about a center position to adjust the specified trajectory, the center position being one of a top and a bottom dead center position of the slide and the connecting rod, means for guiding the slide drive device, a connecting link operably connects the adjusting means to the guiding means, the guiding means being effective to convert the reciprocating motion to a guiding displacement, a drive branching link in the guiding means, a first and a second upper toggle means for transferring the guiding displacement to the slide, a rotation center on each the first and second upper toggle means, the rotation center permitting the first and second upper toggle means to rotate in an arc, the drive branching link being effective to transfer the guiding displacement to the one upper toggle means whereby the slide operates in an adjustable cycle, a first link having a first end connects each the rotation center to the drive branching link, the drive branching link effective to transfer the guiding displacement to each the first and second upper toggle link means along an common inner tangent line to each the arc between the first ends, a first and a second lower toggle link, a second link operably connects each the rotation center to each the respective lower toggle link, and the first and second upper toggle means operably transfer the guiding displacement through the second links to respective first and second lower toggle links and the slide whereby the slide operates through the cycle while maintaining a left and right balance.  
           [0040]    The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0041]    [0041]FIG. 1 is front view of a press according to a first embodiment.  
         [0042]    [0042]FIG. 2 is a descriptive view showing the links for the first embodiment.  
         [0043]    [0043]FIG. 3 is a descriptive view showing changes in the stroke for one part of the first embodiment.  
         [0044]    [0044]FIG. 4 is a figure showing the slide motion for the first embodiment.  
         [0045]    [0045]FIG. 5 is a descriptive view of the slide drive device representing a second embodiment of the present invention.  
         [0046]    [0046]FIG. 6 is a descriptive view of the slide drive device representing a third embodiment of the present invention.  
         [0047]    [0047]FIG. 7 is a descriptive view of the slide drive device representing a fourth embodiment of the present invention.  
         [0048]    [0048]FIG. 8 is a descriptive view of the slide drive device representing a fifth embodiment of the present invention.  
         [0049]    [0049]FIG. 9 is a descriptive view of the slide drive device representing a sixth embodiment of the present invention.  
         [0050]    [0050]FIG. 10 is a descriptive view of the slide drive device representing a seventh embodiment of the present invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0051]    Referring to FIGS. 1 and 2, a press  1  includes a frame  2 . A main motor  3  on frame  2  and serves as a power source for press  1 . Power from main motor  3  transfers through a belt  5  to a fly wheel  4 . A bolster  6  is affixed to frame  2  below press  1 .  
         [0052]    A slide  7  is in frame  2 . Slide  7  operates smoothly in frame  2  above bolster  6 . An upper mold (not shown) is attached to slide  7 . A lower mold (not shown) is attached to bolster  6 . A pair of plungers  36  drive slide  7 . During operation, the upper mold and lower mold are brought together to conduct pressing, as will be explained. During operation, slide  7  and plungers  36  are each guided by a guiding device (not shown).  
         [0053]    A crank shaft  8  is rotatably affixed in frame  2 . An eccentric part  9  is on crank shaft  8 . Fly wheel  4  is connected to one end of crank shaft  8 . A connecting rod  11  has a large end and a small end. The large end is connected to eccentric part  9 . The small end is connected to a pin  12  of a slider  13 .  
         [0054]    A guide board  14  is retained on frame  2 . Guide board  14  can be pivoted and adjusted on frame  2 . Guide board  14  has a linear groove  15 . Slider  13  is slidably inserted in linear groove  15 . In operation, Slider  13  can slide linearly along linear groove  15 , as will be explained.  
         [0055]    Guide board  14  has a rotation center that is a bottom dead center position of the small end of connecting rod  11 .  
         [0056]    It is to be understood that in FIG. 1, the solid line represents press  1  at a bottom dead center position, and the dashed line represents press  1  at a top dead center position, as will be explained.  
         [0057]    It is to be further understood that in FIG. 2, each of the links is shown when press  1  is at the top dead center position.  
         [0058]    It is to be understood, that although no particular mechanism is provided for pivoting and maintaining guide board  14  at a desired angle, it is to be understood that mechanisms exist for such adjustment, for example a worm wheel on an arc section of guide board  14  pivoted by a worm.  
         [0059]    An adjusting mechanism  10  is constructed from linear slider  13  and pivotable guide board  14 .  
         [0060]    A linear guide mechanism  20  is in a center of an upper part of frame  2 . Linear guide mechanism  20  is directly below the bottom dead center position of the small end of connecting rod  11 . Linear guide mechanism  20  is directly below the pivoting center of guide board  14 .  
         [0061]    Linear guide mechanism  20  includes a base  22  and a slider  23 . Base  22  has a groove  21  in a vertical direction. Slider  23  is slidably inserted in groove  21 .  
         [0062]    Slider  23  has an upper support point pin  24  and a lower support point pin  25 . A connecting link  26  rotatably connects upper support point pin  24  and pin  12  of slider  13 .  
         [0063]    It is to be understood, that in configurations where connecting link  26  does not interfere with other members of the slide drive device, the upper support point pin  24  and lower support point pin  25  may be alternatively combined into a single support point pin.  
         [0064]    A pair of fixed support point pins  31 ,  31  are in the upper part of frame  2  of press  1 . Fixed support point pins  31 ,  31  are at left and right symmetric position opposite a common center line.  
         [0065]    A pair of upper toggle links  30 ,  30  are swingably mounted on support point pins  31 ,  31 . Fixed support point pins  31 ,  31  serve as centers of oscillation for upper toggle links  30 ,  30 .  
         [0066]    Upper toggle links  30  is generally shaped as an isosceles triangle. A first link  32  extends from upper toggle links  30  and serves as a first side of the isosceles triangle. A second link  33  extends from upper toggle links  30  serves as a second side of the isosceles triangle.  
         [0067]    A pair of first pins  34  are opposite fixed support point pins  31  on upper toggle links  30 . First pins  34  are each on the other end of each first link  32 . A pair of drive branching links  27  rotatably connects each first pin  34  to lower support point pin  25 .  
         [0068]    A pair of second pins  35  are opposite fixed support point pins  31  on upper toggle links  30 . Second pins  35  are each on the other end of each second link  33 . A connecting pin  37  is on an end of each plunger  36 . Each plunger  36  is upright on slide  7 . A lower toggle link  40  connects each second pin  35  with each connecting pin  37 .  
         [0069]    A pair of balancer links  41  each rotatably connect to connecting pins  37  at a first end. Each balancer link  41  also connects to the end of each plunger  36  at the first end.  
         [0070]    A support link  43  supports a central part of each balance link  41 . Support links  43  are each swingably mounted on a fixed support point  42  on frame  2 .  
         [0071]    A pair of retention links  45  are rotatably connected to a pair of dynamic balancers  44 . The upper part of each dynamic balancer  44  connects to fixed support point pin  31  of upper toggle link  30  through retention link  45 .  
         [0072]    During operation crank shaft  8  rotates and connecting rod  11  oscillates. Slider  13 , connected to the small end of connection rod  11  through bin  12  reciprocates along groove  15  of adjusting mechanism  10 . Connecting link  26  converts this reciprocating motion to a substantially vertical reciprocating motion of slider  23  in linear guide mechanism  20 . It is to be understood, that descriptive phrases vertical or horizontal or otherwise are used for convenience and are not required for operation in other orientations.  
         [0073]    Slider  23  connects to each branching link  27  through lower support point pin  25 . Each branching link  27  converts the vertical reciprocation of slider  23  into oscillation of each upper toggle link  30 .  
         [0074]    The oscillation of each upper toggle link  30  is transferred from first link  32  to second link  33  through fixed support point pin  31 . Each lower toggle link  40  converts the oscillation of each upper toggle link  30  to each plunger  36 . Each plunger  36  transfers motion to slide  7 , and slide  7  operates. Simultaneously, each lower toggle link  40  transfers motion to each balancer link  41 . Each balancer link  41  moves each balancer  44  moves vertically in the opposite direction of slide  7 .  
         [0075]    It is to be understood that in the slide drive device of the present configuration vibration is minimized and operational stresses are reduced.  
         [0076]    Additionally referring now to FIG. 3, the drive mechanism for linear guide mechanisms  20  are symmetric to a center line (not shown) and only one side is shown for clarity.  
         [0077]    A slope angle α (alpha) is defined between a horizontal line through the rotation center of guide board  14  of adjusting mechanism  10  and groove  15 .  
         [0078]    When groove  15  is at slope angle α, the reciprocating motion of slider  13  is fixed at slope angle α. During the reciprocating motion of slider  13  at slope angle α, the motion of slider  13  is between a position of pin  12  and a position  12   a.    
         [0079]    During adjustment, guide board  14  is pivoted and the slope angle of groove  15  becomes a slope angle β (beta). Slope angle β (beta) is defined between a horizontal line through the rotation center of guide board  14  and the now adjusted groove  15 . When groove  15  is at slope angle β, the reciprocating motion of slider  13  is fixed at slope angle β. During the reciprocating motion of slider  13  at slope angle β, the motion of slider  13  is between a position of pin  12  and a position  12   b.    
         [0080]    It is to be understood, that guide board  14  has a center that is a bottom dead center position of the small end of connecting rod  11 , or in other words the position of pin  12 .  
         [0081]    During operation, the length of connecting link  26  remains constant. During adjustment, the vertical reciprocating motion of slider  23  remains vertical. During reciprocating operation before adjustment, the position of upper support point pin  24  changes from a position of upper support point pin  24  to a position  24   a . During operation after adjustment the position of upper support point pin  24  changes from a position of upper support point pin  24  to a position  24   b.    
         [0082]    Similarly, before adjustment, the reciprocating motion of lower support point pin  25  is between a position of lower support point pin  25  and a position  25   a . After adjustment, the reciprocating motion of lower support point pin  25  is between a position of lower support point pin  25  and a position  25   b.    
         [0083]    Before adjustment, the oscillation range of first pin  34  is between a position of first pin  34  and a position  34   a . After adjustment, the oscillation range of first pin  34  is between a position of first pin  34  and a position  34   b.    
         [0084]    Before adjustment, the oscillation range of second pin  35  is between a position of second pin  35  and a position  35   a . After adjustment, the oscillation range of second pin  35  is between a position of second pin  35  and a position  35   b.    
         [0085]    Before adjustment, the reciprocating motion of connecting pin  37  is between a position of connection pin  37  and a position  37   a . After adjustment, the reciprocating motion of connection pin  37  is between a position of connecting pin  37  and a position  37   b.    
         [0086]    As a result, without changing the position of the bottom dead center, the position of the top dead center changes the same amount as the change in the position of connecting pin  37 . As a result, stroke of slide  7  is changed without changing the position of the bottom dead center.  
         [0087]    Additionally referring now to FIG. 4, a motion of slide  7  is shown and compared to a sine curve. The motion of slider  13  at slope angle α is shown. The motion of slider  13  at slope angle β is also shown. The crank angle at the bottom dead center position is 180 degrees.  
         [0088]    As an example, when slope angle α is 32 degrees  40 ′, the crank angle at the top dead center position is 348 degrees  30 ′, and the slide stroke is 50 mm. When the slope angle β is 10 degrees  30 ′, the crank angle at the top dead center is 357 degrees, and the slide stroke is 15 mm.  
         [0089]    As is shown, by changing the slope angle of groove  15 , the slide stroke can be change while maintaining a constant bottom dead center position. As is also shown, even when the slide stroke is changed the left-to-right balance of the slide drive device does not change. Although the change in the slope angle causes a slight change at the top dead center position between slope angle α and slope angle β, this is not a concern in practice.  
         [0090]    Additionally referring now to FIG. 5. showing a second configuration of the present invention. In this embodiment, linear guide mechanism  20  of the first embodiment is changed.  
         [0091]    The small end of connecting rod  11  is at the bottom dead center position. The position of each link is represented by a thick solid line. The position of each pin is represented by a large black dot.  
         [0092]    When the small end of connecting rod  11  is at the top dead center position, the position each link is represented by a thick dashed line with small black dots for the positions of the pins.  
         [0093]    Where the slope angle is β the small end of connecting rod  11  is at the top dead center position, each link is represented by a thin solid line with small circles for the positions of the pins.  
         [0094]    A pair of upper toggle links  50  are pivotably mounted on each left and right fixed support point pin  31 . Upper toggle links  50  are similarly positioned as were upper toggle links  30  in the first embodiment.  
         [0095]    A first link  32  is on each upper toggle link  50 . First links  32  extend toward the center of linear guide mechanism  20 . First links  32  are of equal lengths. First links  32  extend from fixed support point pins  31  to first pins  34 .  
         [0096]    A second link  33  is on each upper toggle link  50 . Second links  33  extend below adjusting mechanism  10 . Second links  33  are of equal lengths. Second links extend from first support point pins  31  to second pins  35 .  
         [0097]    During operation, upper toggle links  50 , first links  32 , and second links  33  operate in are-shaped trajectories. The arc-shaped trajectories have first support pins  31  as a rotation center. During operation, each arc-shaped trajectory has a common inner tangent between two tangent points.  
         [0098]    A drive branching link  51  connects left and right first pins  34  at a pitch of the distance between the two inner tangent points. It is to be understood, that the two tangent points are common to each arc-shaped trajectory where the left and right first links  32  are parallel to each other. It is to be understood, that the second links  33  are at symmetric positions relative to a common center line between fixed support point pins  31 .  
         [0099]    A central support point pin  52  is at the midpoint of drive branching link  51 . Central support point pin  52  connects connecting through link  26  to pin  12 .  
         [0100]    In the second embodiment, linear guide mechanism  20  extends between left and right upper toggle links  50 . Linear guide mechanism  20  includes drive branching link  51  and central support pin  52 .  
         [0101]    First links  32 , second links  33 , upper toggle links  50 , and drive branching link  51  form a type of Watt link mechanism and parallelism between related components is easily maintained.  
         [0102]    During operation, drive branching link  51  has an approximately linear motion along the above-described common inner tangent line. Through the operation of linear guide mechanism  20 , the oscillation of connecting rod  11  and connecting link  26  are converted into substantially linear motion and transferred to each upper toggle link  50 . This conversion from oscillation to substantially linear motion reduces vibration and increases adjustment precision.  
         [0103]    During adjustment, when a slope angle is adjusted slide  7  may be moved with great precision while maintaining the left-right balance of the slide device. It is to be understood, that maintaining precision adjustment of a slide and maintaining left-right balance is desirable for manufacturers to increase efficiency.  
         [0104]    Additionally referring now to FIG. 6, describing a third embodiment of the slide drive device according to the present invention. In this embodiment, slope angle α is defined with respect to the horizontal. In this embodiment, only adjusting mechanism  10  of the first embodiment is changed.  
         [0105]    When the small end of connecting rod  11  is at the bottom dead center position, each of the respective links is represented by a thick solid line, and each respective pin by a solid black dot.  
         [0106]    When the small end of connecting rod  11  is at the top dead center position, each of the respective links is represented by a dashed line, and each respective pin by a solid black dot.  
         [0107]    When the slope angle is slope angle β, the small end of connecting rod  11  is at the top dead center position and each of respective link is represented by a thin solid line with the positions of the pins as small circles.  
         [0108]    A trajectory center pin  62  is on a guide board  61 . Guide board  61  is pivotable around a center of the bottom dead center position of the small end of connecting rod  11 .  
         [0109]    A trajectory forming link  63  operably connect trajectory center pin  62  to pin  12 . Pin  12  is at the small end of connecting rod  11 . Connecting link  26  operably connects pin  12  to upper support point pin  24  of linear guide mechanism  20 . Adjusting mechanism  10  of the third embodiment thus includes at least pin  12 , trajectory center pin  62 , trajectory forming link  63 , guide board  61  and connecting link  26 .  
         [0110]    During operation, crank shaft  8  rotates and the small end of connecting rod  11  reciprocates. The small end of connecting rod  11  reciprocates from the bottom dead center position of pin  12  to top dead center position  12   a  of pin  12 . Due to the combined action of guide board  61 , trajectory center pin  62 , and trajectory forming link  62 , small end of connecting rod  11  has an arc-shaped trajectory between the position of pin  12  and position  12   a.    
         [0111]    Connecting link  26  transfers the reciprocating motion of connecting rod  11  to slider  23 . Upper support point pin  24  on slider  23  linearly reciprocates between the position of upper support point pin  24  and a position  24   a  at the end of each stroke cycle.  
         [0112]    During adjustment, guide board  61  is pivoted and the position of trajectory center pin  62  is moved to a position  26   b . During operation after adjustment, the small end of connecting rod  11  reciprocates through an arc-shaped trajectory from the bottom dead center position of pin  12  and to top dead center position  12   b  of pin  12 .  
         [0113]    During operation after adjustment, slider  23  of linear guide mechanism  20  vertically reciprocates between the bottom position of upper support point pin  24  and upper position  24   b.    
         [0114]    During operation before adjustment, the substantially linear motion of connecting pin  37  is between the position of connecting pin  37  and position  37   a.    
         [0115]    During operation after adjustment, the substantially linear motion of connecting pin  37  is between the position of connecting pin  37  and position  37   b.    
         [0116]    Since connection pins  37  connect each through plungers  36  to slide  7 , the top dead center position of slide  7  can be changed without changing the position of the bottom dead center.  
         [0117]    It is to be understood, that changes in the slide stroke of slide  7  may be conducted in various manners according to manufacturer demand or customer need. For example changes in the slide stroke may be conduced by combining adjustment mechanism  10  of this third embodiment with linear guide mechanism  20  of the second embodiment (described above). For another example, changes in the slide stroke and operational efficiency of slide drive device  1  of the third embodiment may be accomplished through combination with the equipment for dynamic balancer  22  of the first embodiment. In each example, the top dead center position may be adjusted without changing the bottom dead center position.  
         [0118]    Additionally referring now to FIG. 7, where a fourth embodiment of the present invention places adjusting mechanism  10  below linear guide mechanism  20 . The fourth embodiment operates in a substantially similar manner to the first embodiment. The thick, thin, and dashed lines and corresponding pin indicators are the same as above to designate operation before and after adjustment.  
         [0119]    Drive shaft  8  with eccentric part  9  are placed below upper toggle links  30 . Drive shaft  8  with eccentric part  9  are also below adjusting mechanism  10  and linear guide mechanism  20 . Adjusting mechanism  10  is below linear guide mechanism  20 .  
         [0120]    Dynamic balancers  44  are positioned outward from fixed support point pins  31  and upper toggle links  30 . Dynamic balancers  44  operate in an arc-trajectory around a fixed support pin (shown but not described) and act to minimize operational vibration and equipment wear. Dynamic balancers  44  connect to upper toggle links  30  through arc-shaped links and extensions (both shown but not described).  
         [0121]    Additionally referring now to FIG. 8 describing the fifth embodiment of the present invention. In this embodiment, crank shaft  8  is placed below adjusting mechanism  10 . Adjusting mechanism  10  is placed below linear guide mechanism  20 .  
         [0122]    Connecting link  26  rotatively extends from pin  12  to one end of drive branching link  51  at one of first pins  34 . First pins  34  are at both ends of drive branching link  51  and connect to first links  32 .  
         [0123]    The assembly of the fifth through seventh embodiment is different from the second embodiment of FIG. 5, where connecting link  26  extended from pin  12  to central support point pin  52  of drive branching link  51 .  
         [0124]    It is to be understood, that the present invention may be implemented by connecting connecting link  26  with any position along drive branching link  51 .  
         [0125]    Additionally referring now to FIG. 9, describing the sixth embodiment of the present invention. In this embodiment, crank shaft  8  is placed below adjusting mechanism  10 . Adjusting mechanism  10  is placed above linear guide mechanism  20 .  
         [0126]    Additionally referring now to FIG. 10, describing the seventh embodiment of the present invention. In this embodiment, crank shaft  8  is placed above adjusting mechanism  10  and linear guide mechanism  20 . Adjusting mechanism  10  is below linear guide mechanism  20 .  
         [0127]    It is to be further understood, that in each embodiment above, the bottom dead center position of the small end of connecting rod  11  is fixed and the top dead center position is adjustable. Through adjusting the top dead center position of the small end of connecting rod  11 , the top dead center position of slide  7  may be adjusted without changing the bottom dead center position of slide  7 . As a result, according to each embodiment of the present invention the slide stroke of slide  7  may be easily adjusted without changing the bottom dead center position.  
         [0128]    It is to be further understood, that in each embodiment of the present invention, it is possible to fix one of either the top or bottom dead center position of slide  7  and adjust the slide position relative to the fixed top or bottom center position according to customer or manufacturer desire. It is to be understood that this adaptation is possible through easy reconfiguration of adjusting mechanism,  10 , linear guide mechanism  20 , and the other components in press  1 .  
         [0129]    Since the slide drive device of the present invention is a mechanical device, by adjusting the angle of first links  32  and second links  33  of upper toggle links  30 ,  50 , the top dead center position of the small end of connecting rod  11  may be fixed and the bottom dead center adjusted adjustable. As a result, the stroke of slide  7  may be fixed at a top dead center position and the bottom dead center position adjustable.  
         [0130]    It is to be understood, that since the present invention allows slide stroke adjustment to occur before the left and right drive branching.  
         [0131]    It is to be understood, that since slide stroke adjustment occurs before the left and right branching, the left and right balance will remain despite any adjustment.  
         [0132]    It is to be understood, that since slide stroke adjustment occurs before the left and right drive branching, adjustment of the slide stroke is not substantially related to the overall precision of the press, since either the top or bottom dead center position is fixed and the other adjustable.  
         [0133]    It should be also understood, that since the adjustment occurs through guide boards  14  or  61  and the other links and pins of the present invention, precise adjustment of the slide stroke can be made easily.  
         [0134]    It is to be understood, that the motion of the small end of connecting rod  11  is converted with high precision to a reciprocating motion along a linear trajectory in guide boards  14 ,  61 , where pin  12  has a linear motion relative to press  1 .  
         [0135]    It is to be further understood, that since guide boards  14 ,  61  may be rotated with precision to change the slope of the trajectory, the slide drive device may be adjusted with high precision and a simple mechanism.  
         [0136]    It is to be understood, that the motion and the motion of pin  12  may be guided in an arc-shaped motion, relative to press  1 , by trajectory forming link  63  and trajectory center pin  62  thereby minimizing mechanical stress.  
         [0137]    It is to be understood, that where the motion of pin  12  to press  1  is either linear or arc-shaped, the slope of the trajectory can be changed by pivoting guide boards  14 ,  61  to a desired angle.  
         [0138]    It is to be understood that linear guide mechanism  20  may provide reciprocating motion along a vertical linear line or along an inclined linear line depending upon the embodiment. In either case, the left and right balance is maintained with efficiency and precision and equipment life is maintained.  
         [0139]    It is to be understood that where linear guide mechanism  20  provides reciprocating motion along a vertical linear line, the first, third or fourth embodiments using slider  23  and base  22  are employed.  
         [0140]    It is to be understood that where linear guide mechanism  20  provides reciprocating motion along an inclined linear line, the second, fifth, sixth or seventh embodiments employ drive branching links  27 ,  51  to simplify the device and maintain precision.  
         [0141]    Although only a single or few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiment(s) without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described or suggested herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus although a nail and screw may not be structural equivalents in that a nail relies entirely on friction between a wooden part and a cylindrical surface whereas a screw&#39;s helical surface positively engages the wooden part, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.  
         [0142]    Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.