Abstract:
A slider link press includes an oscillation link operating about a fulcrum shaft and an eccentric crank pin. A connecting link connects the oscillation link to a slide. The oscillating link and fulcrum shaft act to increase press torque, reduce downward press speed, and increases upward press speed thereby maintaining cycle time. The eccentric crank pin operates the oscillation link, aids in torque increase, and provides reciprocating movement to the slide. The slide includes pivotable slide gibs that engage reciprocal fixed gibs to maintain parallel surface contact and absorb and eliminate eccentric loads on the slide and the press. Stays and spacers align sides of the press and eliminate flexing under load while absorbing and distributing deformation pressure.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a slider link press. More precisely, the present invention relates to a slider link press having high operational precision and increased pressing force.  
           [0003]    2. Description of the Related Art  
           [0004]    Japanese Laid-Open Patent Publication No. 11-226788, presently owned by Applicant, is an example of a slider link press. The slider link press includes a crank shaft that rotates in a horizontal direction on a frame above a slide. An oscillating link is perpendicular to the crank shaft and faces a roughly horizontal direction. The oscillating link pivots in a reciprocating manner around an oscillation fulcrum shaft as a center. The oscillation fulcrum shaft is parallel to and at a separate position from a crank shaft. A slider joins rotatably with a crank pin on the crank shaft and is slidable in a linear groove provided in the longitudinal direction of the oscillating link.  
           [0005]    A vertical connecting link, has two ends connected in a freely oscillating manner between a lower surface of the oscillating link and the upper surface of the slide. The rotation output of the crank shaft is converted to a reciprocating motion by the oscillating link and the slide operates.  
           [0006]    In this related art, the crank shaft is aligned through the front of the slide press, and the oscillating link is perpendicular with this crank shaft. A hole for a crank shaft is perforated on a left-side plate and a right-side plate in the crown. This requirement greatly weakens the frame body and reduces rigidity during operation. This requirement further forces drive mechanisms (motor and fly wheel) to one side of the slide link press, resulting in instability and loss of balance. Compensation for these drawbacks requires a large and expensive frame to minimize vibration and maintain alignment. This cure fails to increase productivity.  
           [0007]    Japanese Laid Open Utility Model Publication No. 63-56996, is an example of a rigid press machine requiring a tubular spacer inserted between each column in a front-back and left-right direction. A supporting tie rod passes through the spacer and the columns on either side and binds them together. As a result, the deformation in the columns under load is reduced, and working precision is improved.  
           [0008]    However, while the interval between the columns can be maintained, the cross-sectional area of the spacer is small, and the deformation stress of the columns cannot be absorbed. Thus, when an eccentric load is applied on the slide, an edge of the slide contacts the slide guide in a linear manner and ‘slide galling’ frequently results and permanently damages the slide guide. When this type of linear contact ‘slide galling’ occurs, the slide does not operate smoothly and work precision and productivity greatly suffer.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0009]    It is an object of the present invention is to provide a rigid slider link press.  
           [0010]    It is another object of the present invention to provide a press with a slide link where the slide decent time is slowed and the ascent time is speeded up.  
           [0011]    It is another object of the present invention to provide a press where press torque is increased at bottom dead center.  
           [0012]    It is another object of the present invention to provide a press where a center of gravity of a fly wheel is lowered and vibration is reduced.  
           [0013]    It is another object of the present invention to provide a press that withstands and absorbs eccentric loads placed on a slide and operates smoothly without undue wear.  
           [0014]    It is another object of the present invention to provide a press where a stay and spacer absorb and distribute deformation pressure and prevent frame damage.  
           [0015]    It is another object of the present invention to provide a press with horizontal rigidity during press operations.  
           [0016]    Briefly stated, the present invention relates to a slider link press which includes an oscillation link operating about a fulcrum shaft and an eccentric crank pin. A connecting link connects the oscillation link to a slide. The oscillating link and fulcrum shaft act to increase press torque and reduce downward press speed while increasing upward press speed. The eccentric crank pin operates the oscillation link, aids in torque increase, and provides reciprocating movement to the slide. A slide includes pivotable slide gibs that engage reciprocal fixed gibs to maintain parallel surface contact and absorb and eliminate eccentric loads on the slide and press. Stays and spacers align sides of the press and eliminates flexing under load while absorbing and distributing eccentric deformation pressure.  
           [0017]    According to an embodiment of the present invention, there is provided a slider link press device, comprising: a crank shaft and a fulcrum shaft, first means for linking the crank shaft to the fulcrum shaft, the first means being operable in a first arc about the fulcrum shaft, a crank pin on the crank shaft, the crank pin providing an eccentric displacement to the first means, a slide having a top and a bottom dead center position, second means for linking of the first means to the slide, the first means being effective to receive the eccentric displacement and to operate in the first arc to drive the slide in a cycle, the first means perpendicular to the crank shaft and the fulcrum shaft, the first means permitting an increase in a force applied to the slide at the bottom dead center position and permitting an increase in a slide descent time whereby a precision increases and a slide assent time decreases, guiding means for guiding the slide in a cycle, and the guiding means permitting elimination of eccentric loads upon the slide while the slide operates in the cycle whereby the precision increases.  
           [0018]    According to another embodiment of the present invention there is a slider link press device, wherein: the fulcrum shaft includes a fulcrum shaft center, the first link means is horizontal to the fulcrum shaft center at the bottom dead center position, the eccentric displacement is a trajectory circle, an angular velocity of the crank shaft is constant, a first position (O) is a rotation center of the crank shaft, a first tangent point (PT) is defined on the trajectory circle at the top dead center position respective to the fulcrum shaft center, a second tangent point (PR) is defined on the trajectory circle at the bottom dead center position horizontal to the fulcrum shaft center, a first angle (θ1) is a first link means oscillation angle between the first tangent point (PT), the fulcrum shaft center, and the second tangent point (PR), a second angle (θ2) is defined between the first tangent point (PT), the first position (O), and the second tangent point (PR), the first angle (θ1) and the second angle (θ2) have the following relationship, and 
           (θ2)minimum=180 degrees−(θ1)  (I) 
           (θ2)maximum=180 degrees+(θ1)  (II) 
           [0019]    the second link means descends under formula (II) whereby the a torque at the bottom dead center is increased and decent time is increased.  
           [0020]    According to another embodiment of the present invention there is provided a slider link press device, wherein: a distance L1 is defined between a maximum eccentricity of said crank pin  11  and said fulcrum shaft center, a distance L2 is defined between the center of said first link means and said fulcrum shaft center, a center of said first link means is a center axis of said slide, a first torque applied to said crank pin is F1, a second torque applied to said slide is F2, said first torque is at a minimum where F1=F2 and said slide is at said top and bottom dead center positions, said slider link press effective to increase during an operating cycle of said slide as said crank pin travels from the top dead center to the bottom dead center, and said second torque is at a maximum at a maximum eccentricity of said crank pin and where F 2 =F 1 ×L 1 /L2 and said first means is effective to increase said second torque.  
           [0021]    According to another embodiment of the present invention there is a slider link press device, further comprising: a drive assembly, the drive assembly effective to drive the crank shaft, a speed reducing module and a fly wheel in the drive assembly, a frame assembly supporting the drive assembly and the slide, and the crank shaft above the slide.  
           [0022]    According to another embodiment of the present invention there is a slider link press device, wherein: the frame assembly includes a crown assembly, the crown assembly above the slide, the first link means, the crank shaft, and the fulcrum shaft in the crown assembly, and the fly wheel having a center of gravity below the crown, whereby stability is increased and operating vibration is reduced.  
           [0023]    According to another embodiment of the present invention there is a slider link press device, wherein: the slide includes a vertical slide center, the slide center being a press center, and the rotation center vertically aligned with the press center.  
           [0024]    According to another embodiment of the present invention there is a slider link press device, further comprising: at least first and second columns in the frame, the first and second columns below the crown, at least first and second stays, the first and second stays between the first and second columns at the bottom dead center position, and the first and second stays operably joining the first and second columns whereby the columns are maintained parallel and the frame is rigid and resists high operating pressure and eccentric slide pressure.  
           [0025]    According to another embodiment of the present invention there is a slider link press device, further comprising: a plurality of vertical comer surfaces on the slide, a plurality of fixed gibs on the guiding means, the fixed gibs along inner surfaces of the first and second columns, the fixed gibs opposite the slide, the fixed gibs aligned adjacent to the comer surfaces, the comer surfaces being slidably aligned with the fixed gibs, a plurality of slide gibs on the guiding means, the plurality of slide gibs on the corner surfaces, the slide gibs having an engagement surface parallel to the fixed gibs, and means for pivoting the slide gibs relative to the fixed gibs, and the pivoting means effective to maintain the engagement surfaces parallel to the fixed gibs whereby the fixed gibs slidably guide the slide and eliminate eccentric forces on the slide.  
           [0026]    According to another embodiment of the present invention there is a slider link press device, further comprising: a plurality of holes in the pivot means, the slide gibs in each the hole, the slide gibs pivotable in each the hole, the holes at a top and bottom side of each the corner surface, the first and second stays are equidistant the slide gibs when the slide is at the bottom dead center position, and the stays, the slide gibs, and the pivot means absorb eccentric forces whereby the first and second columns are maintained in parallel and the slide operates parallel to the fixed gibs.  
           [0027]    According to another embodiment of the present invention there is a slider link press device, further comprising: at least one spacer, the spacer between each the stay and each respective the first and second column, the spacer selectable to maintain the first and second columns in parallel, and the spacer being effective as a slip plane whereby the spacer minimizes damage to the first and second columns during tightening the stays.  
           [0028]    According to another embodiment of the present invention there is provided a slider link press, having a slide operated by converting a rotational crank shaft output converted to a reciprocating motion by an oscillating link, comprising: an oscillation fulcrum shaft, the oscillation fulcrum shaft parallel to the crank shaft, the oscillating link effective to operably join the oscillation fulcrum shaft and the crank shaft, the oscillating link receiving the output as an eccentric displacement, the oscillating link operation in an arc about the oscillation fulcrum shaft, crank pin on the crank shaft, the crank pin effective to transfer the eccentric displacement to the oscillating link, and the oscillating link effective to transfer the reciprocating motion to the slide and act as a force multiplier whereby the slide operates with increased pressing force, has a lower descent time and a faster ascent time.  
           [0029]    According to another embodiment of the present invention there is provided a slider link press, further comprising: a speed reduction module, a fly wheel, the speed reduction module and the fly wheel effective as drive modules for the crank shaft, a frame, the frame including the drive modules and the slide, the fly wheel and the speed reduction modules effective to provide the eccentric displacement to the crank pin whereby the slide operates in a cycle.  
           [0030]    According to an embodiment of the present invention there is provided a slider link press device in which a frame includes first and second columns, and a slide operates between the columns, comprising: first and second stays, the first and second stays between the first and second columns, the first and second stays effective to rigidly join the first and second columns, and the first and second stays effect to resist an eccentric force of the crank shaft whereby the first and second columns are maintained in parallel.  
           [0031]    According to another embodiment of the present invention there is provided a slider link press device, further comprising: at least one spacer, the spacer between each the first and second column and each respective the first and second stay, and the spacer having a thickness effective to maintain the first and second columns in parallel.  
           [0032]    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  
       [0033]    [0033]FIG. 1 is a front view of the principal parts of a slide press.  
         [0034]    [0034]FIG. 2 is a longitudinal side view of FIG. 1.  
         [0035]    [0035]FIG. 3 is a partial rear view of FIG. 1.  
         [0036]    [0036]FIG. 4 is a view of an oscillating link with a slide at a bottom dead center position.  
         [0037]    [0037]FIG. 5 is a view of an oscillating link with a slide at a top dead center position.  
         [0038]    [0038]FIG. 6 is a motion model diagram of the oscillating link.  
         [0039]    [0039]FIG. 7 is a comparative diagram of motion waveforms for the press.  
         [0040]    [0040]FIG. 8 is a comparative diagram of motion waveforms of torque curves for the press.  
         [0041]    [0041]FIG. 9 is a working torque distribution diagram for the press.  
         [0042]    [0042]FIG. 10 is a front view of an embodiment of the press.  
         [0043]    [0043]FIG. 11 is a longitudinal side view of FIG. 10.  
         [0044]    [0044]FIG. 12 is a cross-section from the view along the line A-A in FIG. 10.  
         [0045]    [0045]FIG. 13 is a front view of FIG. 12.  
         [0046]    [0046]FIG. 14 is a partial perspective view FIG. 13.  
         [0047]    [0047]FIG. 15 is a partial view of a stay of FIG. 14.  
         [0048]    [0048]FIG. 16 is a perspective view of a slide.  
         [0049]    [0049]FIG. 17 is a perspective view of a slide gib as seen in FIG. 16. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]    Referring to FIGS. 1 and 2, an embodiment of a slider link press  50  includes a first column  1  and a second column  2 . Columns  1 ,  2  form a left and right side wall of slider link press  50 . A rib  3  joins a bottom portion of columns  1 ,  2 . A pair of stays  4 ,  5  join an upper portion of columns  1 ,  2 . Rib  3  and stays  4 ,  5  act to maintain equal spacing between columns  1 ,  2 , as will be explained.  
         [0051]    A slide  6  operates between stays  4 ,  5  above rib  3 . A bolster  21  is on rib  3  opposite slide  6 . A crown  7  fixes and joins upper parts of columns  1 ,  2 . A front and back rib  9  are included in crown  7 . A crank shaft  8  extends horizontally to crown  7 . Crank shaft  8  is rotatably supported as it passes through the walls of front and back rib  9 .  
         [0052]    An oscillation fulcrum shaft  10  is on a right side of crown  7 . Oscillation fulcrum shaft  10  is generally parallel with crank shaft  8 , as will be explained.  
         [0053]    An oscillating link  12  is pivotably retained on one side by oscillation fulcrum shaft  10 . A crank pin  11  slidably joins oscillating link  12  to crank shaft  8 , as will be explained. Oscillating link  12  operates in a reciprocating arc-type motion about oscillation fulcrum shaft  10 , as will be explained.  
         [0054]    A crank pin insertion window  13  extends in a longitudinal direction in oscillating link  12 . Crank pin  11  is operably retained in insertion window  13  by a pair of sliders  14 ,  15 . Crank pin  11  therefore slides forward and backward during operation relative to oscillating link  12 . Crank pin  11  is eccentric to crank shaft  8 .  
         [0055]    Insertion window  13  of oscillating link  12  includes a base module  12 A and an opposing lid module  12 B. During assembly, crank pin  11  is retained in oscillating link  12  and insertion window  13  by a lid body  12 C. Lid body  12 C is attached to respective base module  12 A and lid module  12 B by bolts or screws. It is to be understood, that lid body  12 C may be affixed to oscillating link  12  by any manner effective to operably retain crank pin  11 .  
         [0056]    Spherical bearings  16  on both an upper surface of slide  6  and a opposing lower surface of oscillating link  12 . Spherical bearings  16  are generally vertically opposite each other. A connecting link  17 , is retained between spherical bearings  16 . Connecting link  17  has spherical ends that rotatably mate with respective spherical bearings  16 . Connecting link  1   7 and spherical bearings  16  mechanically and operably link slide  6  to oscillating link  12 .  
         [0057]    A multistage speed reduction gear assembly  18  connects to a back end of crank shaft  8 . A motor  20  and a fly wheel  19  provide multistage speed reduction gear assembly  18  with drive force. The drive force from multistage speed reduction gear assembly  18  drives a back end of crank shaft  8 .  
         [0058]    It should be understood that an upper and lower die (both not shown) are affixed respectively to a lower surface of slide  6  and to an upper surface of bolster  21 . The dies are used in the pressing of a product.  
         [0059]    Additionally referring now to FIG. 3, a main gear  18 A, of multistage speed reduction gear assembly  18  is in a middle section between a left and a right side column portions  1 A,  2 A. A middle gear  18 B and a fly wheel  19  are also positioned in the middle section and provide drive force to multistage speed reduction gear assembly  18 .  
         [0060]    It should be noted that the center shaft of fly wheel  19  is positioned below crown  7 . The center of gravity of fly wheel  19  is therefore below crown  7  and provides an important stability to slider link press  50 , reduces vibration, and improves safety.  
         [0061]    It should be additionally noted that main gear  18 A, middle gear  18 B, and fly wheel  19  are generally positioned along a vertical centerline between columns  1 ,  2  thereby further centering the center of gravity of speed reduction gear assembly  18 . This positioning further reduces operational vibration.  
         [0062]    Additionally referring now to FIGS.  4  where oscillating link  12  and slide  6  are at a bottom dead center position. In the bottom dead center position, the position of crank pin  11  is aligned with a horizontally extended center line (PR) (not shown) from fulcrum shaft  10 .  
         [0063]    Additionally referring now to FIG. 5, where oscillating link  12  and slide  6  are at a top dead center position. In the top dead center position oscillating link  12  and slide  6  are at a maximum distance in an operational cycle.  
         [0064]    Additionally referring now to FIG. 6, where the operational position of crank pin  11  is shown as tangent points on a trajectory circle of crank pin  11 . The trajectory circle is determined by the eccentric amount of crank  8  and fulcrum shaft  10 .  
         [0065]    At top dead center, the position of crank pin  11  is at a tangent point (PT) on a line that joins the trajectory circle of crank pin  11  with fulcrum shaft  10 .  
         [0066]    At bottom dead center, a position (PR) of crank pin  11  is on a horizontally extending center line of fulcrum shaft  10  of oscillation link  12  and is at a tangent point to the trajectory circle of crank pin  11 .  
         [0067]    An angle theta L (θL) is a link oscillation angle is defined between tangent point (PT), the center of oscillation fulcrum shaft  10 , and horizontal extending center line (PR).  
         [0068]    A position (O) is a rotation center of crank shaft  8 .  
         [0069]    An angle PR-O-PT, connecting tangent points PT and PR is: 
         At a minimum at, angle PR-O-PT=180 degrees−theta L (θL)  (III) 
         At a maximum at, angle PR-O-PT=180 degrees+theta L (θL)  (VI) 
         [0070]    During operation, the angular velocity of crank shaft  8  is constant. By setting the rotation direction of crank shaft  8  so that connecting link  17  is descending when in the above situation (VI), slide  6  of slider link press  50  has a longer descent time and a shorter ascent time and torque is increased.  
         [0071]    During operation, the rotation of crank shaft  8  drives crank pin  11 , and oscillating link  12  oscillates in an up-and-down arc motion. Oscillating link  12  is connected with oscillation fulcrum shaft  10  as a rotation center. Connecting link  17 , operably joined to oscillating link  12  has a corresponding general up-and-down motion.  
         [0072]    Referring additionally now to FIG. 7, a motion comparison is made between a general crank press (solid line with box) and the present embodiment slider link press  50  (solid line with diamond).  
         [0073]    The present embodiment of slider link press  50  is shown through one operation cycle as having a longer and slower descending stroke and a shorter and quicker ascending stroke. It is to be understood, that such modification of the stroke time is beneficial to accuracy and precision. As shown, the general crank press has a low point at 180 degrees of rotation and the present embodiment has a low point beyond 180 degrees. The degree of difference is the time difference. It is to be understood that the total slide  6  cycle time remains the same and that the rate of travel of slide  6  changes during the cycle.  
         [0074]    It should be additionally understood that the horizontal center of crank shaft  8  and a vertical press center (not shown) of slide  6  are aligned on the same vertical axis, further beneficially influencing the cycle time, stroke length, and press torque.  
         [0075]    Additionally referring now to FIG. 8, a torque comparison indicates that the allowable load in the present embodiment is greater than that of a general crank press. This additional load is excellent for precision cold forging and is an important, but not only, result of the present invention.  
         [0076]    It is to be understood, that positioning the elements of the present construction improves both balance and rigidity, reduces the size of slider link press  50 , and improves operational efficiency. Specifically, connecting link  17  is directly above slide  6  and perpendicular to crank shaft  8  while oscillation fulcrum shaft  10  is parallel to crank shaft  8 , thereby increasing left-right symmetry in the device and reducing overall size.  
         [0077]    It is to be further understood, that by positioning the components as listed above and shown in the drawings, frame holes are minimized in slider link press  50  and rigidity and compactness are again improved and vibration restricted.  
         [0078]    It is to be further understood that since speed reduction gear assembly  18  and fly wheel  19 , are positioned between ribs  9  in the back part of crown  7 , the size of slider link press  50  is reduced, balance is improved, vibration reduces, and a higher productivity results.  
         [0079]    It should be further understood, that positioning the center of gravity of fly wheel  19  below the position of crown  7 , vibration is further reduced and stability increased.  
         [0080]    Referring additionally now to FIG. 9, where the center axis of press  50  (slide  6 ) and crank shaft  8  are aligned to the same vertical axis. As described above, the center of crank shaft  8  is defined as O (previously shown). A distance L1 is defined between a maximum eccentricity of crank pin  11  and a center of oscillation fulcrum shaft  10 . A distance L2 is defined between the center axis of connecting link  17 , and the center of oscillation fulcrum shaft  10 .  
         [0081]    The center of connecting link  17  is to be understood as the center axis of slide  6 .  
         [0082]    The pressure (torque) applied to crank pin  11  is defined as F1. The pressure applied to slide  6  is defined as F2. It is to be understood, that the pressure applied on crank pin  11  is at a minimum value where F1=F2 at slide  6  top dead center and bottom dead center positions.  
         [0083]    It is to be further understood, that the pressure (torque) increases during an operating cycle of slider link press  50 , as crank pin  11  travels from the top dead center to the bottom dead center. The combined pressure (torque) at the maximum eccentricity of crank pin  11 , is defined by the formula F2=F1×L1/L2.  
         [0084]    It should be understood, that oscillation link  12  operates as a lever and boots pressure (torque) and power with respect to operating slide crank press  50 . Where L1, maximum eccentricity, increases, pressure (torque) also increases.  
         [0085]    Additionally referring now to FIGS. 10 and 11, a bolster  28  is below slide  6 . Two sets of fixed gibs  25  are vertically mounted on columns  1 ,  2 . Fixed gibs  25  are mounted opposite each vertical corner of slide  6 . Two sets of slide gibs  24  are vertically mounted on each corner of slide  6 . Slide gibs  24  engage and slide on corresponding fixed gibs  25 , as will be explained. Slide gibs  24  have a partially circular construction, as will be explained.  
         [0086]    Additionally referring now to FIG. 12, fixed gibs  25  have the shape of a vertical rectangle. Each outside vertical corner of slide  6  is formed in the shape of an ‘L’ corresponding to the shape of fixed gibs  25 .  
         [0087]    Stays  4 ,  5  are between columns  1 ,  2  adjacent an outer surface of fixed gibs  25 . Stays  4 ,  5  provide extensive support and vibratory damping to slider link press  50 , as will be explained. A spacer  22  inserted on one surface between stays  4 ,  5  and respective columns  1 ,  2  and maintains a required spacing. A required spacing between columns  1 ,  2  is maintained by adjusting a thickness of spacer  22  while retaining rigidity. Spacer  22  also acts to absorb and distribute deformation pressure on columns  1 ,  2  during adjustment of stays  4 ,  5 .  
         [0088]    Additionally referring now to FIGS. 13 and 14, bolts  30  affix stays  4 ,  5  to respective columns  1 ,  2 . Bolts  30  are inserted from an inside surface of stays  4 ,  5 , through spacers  22  and into respective columns  1 ,  2  and tightened to ensure horizontal rigidity and resistance to eccentric loads on slide  6 . It should be understood that additional methods of rigidly affixing stays  4 ,  5  to columns  1 ,  2  are available but must minimize vibration, increase rigidity, minimize deformation and serve similar functions to bolts  30 .  
         [0089]    Additionally referring now to FIG. 15, each stay  4 ,  5  includes a front thick board  42 , a back thick board  43 , and a side board  44 . An open window  41  is formed through the center of boards  42 ,  43 . During assembly, side board  44  is tightened to respective columns  1 ,  2  by bolts  30  from an interior side. Spacer  22  additionally aids in preventing damage, and absorbing and distributing deformation pressure to columns  1 ,  2  during tightening of bolts  30 . To increase horizontal and transverse rigidity, stays  4 ,  5  may be alternatively formed as a single unit or with additional supporting members.  
         [0090]    Additionally referring now to FIG. 16 and  17 , a comer surface  23  is on each vertical comer of slide  6 . Corner surfaces  23  are formed corresponding to fixed gibs  25 , described above. Corner surfaces  23  have an L-shaped cross-section, but may be adapted to other shapes referenced to fixed gibs  25 . Holes  27  are at a top and bottom position of each corner surface  23 , opposite fixed gibs  25 .  
         [0091]    Sliding gibs  24  are in respective holes  27  opposite fixed gibs  25 . Sliding gibs  24  have a circular cross-section corresponding to holes  27  and a two-plane-L-shaped face corresponding to comer surfaces  23 . The L-shaped faces of sliding gibs  24  match the outside corner surfaces of fixed gibs  25 . Sliding gibs  24  rotate within holes  27  to accommodate any torsion placed upon slide  6  during operation, as will be explained.  
         [0092]    It is to be understood, that when slide  6  is at the bottom dead center position, stays  4 ,  5  are positioned, equidistant, between top and bottom slide gibs  24 . As a result, stays  4 ,  5  are positioned to counter the affects of maximum pressure (torsion) during operation. As indicated above, it is to be understood that maximum pressure (torsion) is at the bottom dead center position.  
         [0093]    During normal operations, slide  6 , through connecting link  17  and oscillating link  12  work to maintain alignment between corner surfaces  23  of slide  6  and fixed gibs  25 . Precise balance is difficult to maintain during the complete operation cycle and slide  6  may operate in an non-uniformly parallel manner (i.e. the result of an eccentric load) for a period of time.  
         [0094]    Where an eccentric load operates to shift slide  6 , the L-shaped face of slide gibs  24  contacts the corresponding surface of fixed gibs  25 , and holes  27  allow slide gibs  24  to rotate, maintain parallel contact, accommodate any eccentric load. This operation ensures ensure smooth press operation extends life. Where an eccentric load is larger than expected, the above invention also accommodates additional load through the use and correct positioning of stays  4 ,  5  on columns  1 ,  2 . As a result, the phenomenon of ‘linear contact’ and ‘slide galling’ found in the related art is eliminated and seizure of the guide surfaces and slide  6  is eliminated.  
         [0095]    Further, it is to be understood, that the use of spacers  22  prevents damage to columns  1 ,  2 , by both acting as slip planes to eliminate over-tightening damage, and by acting to ensure spacing alignment with slide  6  to resist eccentric force.  
         [0096]    Since slide gibs  24  have an L-shaped face, there are two surfaces that match the two corresponding surfaces of each fixed gib  25  and, through contact, and rotation maintain alignment of slide  6 . Since slide gibs  24  pivot in the direction of surface contact, the L-shaped face is maintained in parallel, surface contact alignment with the surfaces of fixed gibs  25 .  
         [0097]    In combination, columns  1 ,  2 , stays  4 ,  5 , ribs  3 ,  9 , and the other elements of slider link press  50  easily provide horizontal rigidity to ensure a maximum available pressure (torque) with a low maintenance that is not found in the related art.  
         [0098]    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 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.  
         [0099]    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.