Abstract:
The object of this invention is to provide a mechanical press that presents no inconvenience in press operations despite its low height, providing great stability and excellent durability. The invention comprises a slide guiding mechanism provided at an upper part of the adjusting member for converting the rotary motion of the eccentric part of the crankshaft into a linear reciprocating motion and a position adjusting mechanism provided at a lower part, as well as an adjusting member that advances and retracts relative to the slide, which serves for the prevention of rotation and guidance.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to a mechanical press  
         [0003]     2. Description of the Related Art  
         [0004]     In a typical mechanical press of the prior art, an eccentric part  8   a  of a crankshaft and a slide  3  are connected with a connecting rod  23  as shown in  FIG. 10 . An adjusting screw rod  24  is provided between connecting rod  23  and slide  3  for adjusting the slide. In this example of prior art, the presence of connecting rod  23  prevents the shortening of the distance between the crankshaft and slide  3 , resulting in a taller mechanical press, taller by said distance.  
         [0005]     A mechanical press without a connecting rod was proposed by Unexamined Patent Publication S55-48500. Since no connecting rod exists in said example, the height of the machine can be lowered, but it is impossible to provide an adjusting screw rod for slide adjustment making the press very inconvenient to use in press operations.  
         [0006]     Another example of prior art is the one disclosed by Unexamined Patent Publication H06-269996. As shown in  FIG. 5  of said publication, it comprises: a bush  8  and a sliding piece  9  fitted on an eccentric part  3   a  of a crankshaft  3 ; a connecting rod  10  that slidably contains sliding piece  9 ; and a guide bush  12  provided in a crown for guiding connecting rod  10  in an up and down direction, while connecting rod  10  and a slide  16  are connected via a die height adjusting mechanism  17 .  
         [0007]     According to said prior art, slide  16  cannot be raised higher than the guide part of connecting rod  10  as connecting rod  10  is guided at the crown as mentioned before. In other words, the machine height cannot be shortened any further.  
         [0008]     Another example of prior art is the one disclosed by Unexamined Patent Publication S57-14499. As shown in  FIG. 3  of said publication, a guide plate  11  is guided by guide  12 . Therefore, a slide  2  cannot go any higher than guide  12 , so that the distance between a crankshaft  3  and slide  2  cannot be shortened. Therefore, it is difficult to shorten the height of the machine.  
         [0009]     As mentioned in the above, it is difficult to shorten the machine height in all of these prior art machines if there is a connecting rod or something similar to it is used. On the other hand, machines that can be built shorter in heights present inconveniences in press operations.  
         [0010]     The invention intends to provide a mechanical press that can be built shorter in height without sacrificing convenience in press operations, while providing merits of stability and longevity.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention is to have a slide guiding mechanism provided above an adjusting member for converting a rotational motion of an eccentric part of a crankshaft into a reciprocating straight line motion, a position adjusting mechanism provided below, and a device for guiding and preventing said adjusting member from rotating relative to said slide.  
         [0012]     More specifically, the invention of claim  1  is to provide: a slide guiding mechanism provided above an adjusting member for converting a rotational motion of an eccentric part of a crankshaft into a reciprocating straight line motion in coordination with a slide of the mechanical press; a position adjusting mechanism provided below said adjusting member for advancing or retracting said adjusting member relative to said slide; and a device for guiding and preventing said adjusting member from rotating relative to said slide.  
         [0013]     The invention of claim  2  provides, in addition to the features of claim  1 , wherein said device for guiding and preventing said adjusting member from rotating relative to said slide uses a spherical member that consists of a spherical part and a flat part. The invention of claim  3  provides, in addition to claim  2 , a pair of said spherical members is provided and a guide surface to which said flat part of each spherical member is contacting makes an angle to each other.  
         [0014]     The invention of claim  4  provides, in addition to claim  3 , a block that contains said guide surface having its position adjusted in an axial direction of the eccentric part of the crankshaft. The invention of claim  5  provides, in addition to claim  3  or claim  4 , that the spherical part engages with a concave spherical surface provided in said adjusting member, and the flat part is built into said guide surface in a slidable manner.  
         [0015]     The invention of claim  6  provides, in addition to claim  3  or claim  4 , that said spherical member engages with a concave spherical surface of a receiving member affixed to said adjusting member, and the flat part is built into said guide surface in a slidable manner. The invention of claim  7  provides, in addition to claim  3  or claim  4 , that said spherical member is affixed to said adjusting member, and is built in with a cap on the spherical part.  
         [0016]     The invention of claim  8  provides, in addition to claims  4  through  7 , that said block&#39;s position is adjustable by means of the eccentric pin. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a front view and partial cross section of the press of the present invention;  
         [0018]      FIG. 2  is a left side view and partial cross section of the press of  FIG. 1 ;  
         [0019]      FIG. 3  is a perspective view of an adjoining member of the present invention;  
         [0020]      FIG. 4  is an enlarged view of the adjoining member;  
         [0021]      FIG. 5  is a top view of another embodiment and partial cross section;  
         [0022]      FIG. 6  is a top view and partial cross section of another embodiment of the adjoining member;  
         [0023]      FIG. 7  is a second embodiment of the spherical member;  
         [0024]      FIG. 8  is a third embodiment of the spherical member;  
         [0025]      FIG. 9  is a descriptive view of the eccentric pin; and  
         [0026]      FIG. 10  is a front view of a mechanical press of prior art having a connecting rod. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     In  FIG. 1 , a slide  3  provided on a frame  2  of a mechanical press  1  is free to move up and down, and a bolster  4  is affixed on a frame  2  facing slide  3 . A vibration prevention device  5  is affixed to the lower end of frame  2  for isolating the vibration of the mechanical press from the foundation of the machine.  
         [0028]     Slide  3  is guided for its up and down motion relative to frame  2  by means of a slide guide  18 . Slide  3  is suspending from a balancer  25 . Balancer  25  consists of an air cylinder, and balances the weight of slide  3  and the weight of a top die affixed to the bottom surface of slide  3 .  
         [0029]     In  FIG. 2 , crankshaft  8  is supported by frame  2 . Crankshaft  8  is rotatably supported by bearings provided in frame  2 , and are arranged in the front to back direction relative to frame  2 .  
         [0030]     A main gear  9  is affixed to crankshaft  8 . On the other hand, flywheel  11  is rotatably provided in frame  2 . Flywheel  11  contains a clutch-brake and rotates driven by a motor (not shown). A pinion gear  10  is formed on a shaft on which said clutch-brake is provided. Pinion gear  10  is in mesh with said main gear  9 .  
         [0031]     Crankshaft  8  is driven by a drive mechanism comprising a motor, flywheel  11 , the clutch-brake, pinion gear  10  and main gear  9 . Since flywheel  11  has a relatively large diameter, it is arranged approximately in the same height as crankshaft  8  so that the height of frame  2 , i.e., the height of the mechanical press  1  can be shortened.  
         [0032]     Referring to  FIG. 3  and  FIG. 4 , an adjusting member  12  and its vicinity is described in more detail.  FIG. 3  is similar to  FIG. 4  except that it is a perspective drawing. Slide  3  is shown only partially in  FIG. 3 . Both of these drawings show the system with the crank angle at 180°, slide  3  is at the bottom dead center.  
         [0033]     A slide guiding mechanism  6  and a position adjusting mechanism  7  are provided integrally. Sliding mechanism  6  is provided above and position adjusting mechanism  7  is provided below adjusting member  12 . Adjusting member  12  is covered by a cap  13 , which is affixed with bolts  14  via spacers  15 . Adjusting member  12 , spacer  15 ,  15 , and cap  13  for a frame that has a space in the middle.  
         [0034]     Said space houses an eccentric part  8   a  of crankshaft  8 , an upper sliding piece  16  and a lower sliding piece  17 . Upper sliding piece  16  and lower sliding piece  17  engage with eccentric part  8   a  above and below respectively, while upper sliding piece  16  slides against cap  13  freely, and lower sliding piece  17  slides against adjusting member  12  freely. Slide guiding mechanism  6  consists of upper sliding piece  16 , lower sliding piece  17 , adjusting member  12 , cap  13 , spacer  15 , etc.  
         [0035]     Upper sliding piece  16  and lower sliding piece  17  move laterally relative to said frame. Upper sliding piece  16  and lower sliding piece  17  constitute a so-called split type sliding piece. The split type sliding piece has such merits that it does not need the space for bolts, which are required for binding the upper and lower sliding pieces together, so that the width of each sliding piece can be narrower, that the in and out clearance for the sliding piece can be halved, etc.  
         [0036]     A threaded rod  12   a  is formed at the lower end of adjust member  12 . A nut  21  is fitted to threaded rod  12   a . Nut  21  is assembled into slide  3  in such a way that it is free to rotate but constrained in the vertical direction. Nut  21  is held to slide  3  with a retainer  22 .  
         [0037]     A worm gear  20  is formed on the outside of nut  21 . Worm gear  20  engages with a worm shaft  19  provided rotatably in slide  3 . Worm  19  is driven by a motor (not shown) to rotate. Threaded rod  12   a , nut  21 , worm gear  20 , worm shaft  19 , etc. constitute a position adjusting mechanism  7 , which corresponds to a conventional slide adjusting mechanism.  
         [0038]     Position adjusting mechanism  7  of this embodiment uses a screw mechanism, but the same can be constituted by a hydraulic means. In other words, it can be so constituted to provide a hydraulic cylinder underneath adjusting member  12  in order to move adjusting member  12  relative to slide  3  by means of adjusting the amount of oil. Alternatively, a tapered block can be provided underneath adjusting member  12  in order to move adjusting member  12  relative to slide  3 .  
         [0039]     In  FIG. 4 , when worm shaft  19  rotates, worm gear  20  and nut  21  rotate to elevate adjusting member  12  up and down by means of a screw mechanism. Thus, adjusting member  12  can move forward and backward relative to slide  3 .  
         [0040]     Adjusting member  12  is prevented from accidental rotations by means of a guiding device. In other words, said guiding device has a function of preventing the slide adjustment amount from changing caused by rotations of adjusting member  12  during press operations.  
         [0041]     In  FIG. 4  and  FIG. 5 , a block  27  is built into guide hole  3   a  of slide  3 . Block  27  is affixed to slide  3  by means of eccentric pins  28  and bolts  29 . A spherical member  26  is located between block  27  and adjusting member  12 . Spherical member  26  consists of a spherical part and a flat part and forms a part of a sphere. The height of spherical member  26  is approximately 30% of the diameter of the sphere. Spherical member  26  is stored in a cavity of a spherical shape provided in adjusting member  12  and said flat surface is contacting block  27 . Block  27  has a guide surface.  
         [0042]     In this embodiment, an angle α formed by the planes of contact between block  27  and the flat surfaces of a pair of spherical members  26  is 120°. The angle α is convex, as seen from the block  27  side. This angle is chosen based on the eccentric load acting on adjusting member  12 . It is chosen on the assumption that the eccentric load in the left and right direction is greater than that in the front and back direction. If α is 120°, the ratio of said projected area is {square root}{square root over (3)}:1 due to the trigonometric relation, in other words, approximately 1.7:1.  
         [0043]     The position of block  27  is adjustable by means of eccentric pin  28  in the forward and backward direction (the axial direction of eccentric part  8   a  of crankshaft  8 ). Block  27  is adjusted in order to adjust the inclination of the guiding surfaces of adjusting member  12  in the forward and backward direction relative to upper and lower sliding pieces  16  and  17  (especially sliding piece  17 ). In other words, it is to makes sure that the outer periphery of eccentric part  8   a  of crankshaft  3  and the inner periphery of lower sliding piece  17  as well as the bottom surface of lower sliding piece  17  and the horizontal plane (top surface) of adjusting member  12  make surface contacts respectively.  
         [0044]     Since adjusting member  12  is affixed to slide  3  via threaded rod  12   a , forward and backward adjustments of block  27  cause the horizontal surface (top surface) of adjusting member  12  to tilt forward and backward correspondingly.  
         [0045]     In  FIG. 9 , the cylindrical part on the left end of eccentric pin  28  is off-centered relative to the cylindrical part on the center by an amount “E.” By loosening bolt  29  slightly, engaging the special tool to a twisting hole  35  and turning eccentric pin  28  in the direction of the arrow B, block  27  moves in the direction A. After adjusting block  27 , bolt  29  is tightened to affix block  27  to slide  3 .  
         [0046]      FIG. 6  shows another embodiment and corresponds to  FIG. 5  mentioned above. In case of  FIG. 5 , the guide surfaces of a pair of spherical members  26  form the angle α, which is convex seen from the block  27  side. On the other hand, an angle β in case of FIG.  6  that corresponds to said angle a is concave seen from the blocks  30  and  31  side. As a result, the cross sectional shape of adjusting member  12 ′ is convex toward blocks  30  and  31 . Blocks  30  and  31  are adjustable by means of an eccentric pin  28  as in the case of said block  27 .  
         [0047]      FIG. 7  and  FIG. 8  show other embodiments with different assembling modes for spherical member  26 . In case of  FIG. 7 , a receiving member  32  is provided on adjusting member  12 , while receiving member  32  receives spherical member  26 . In other words, receiving member  32  exists between spherical member  26  and adjusting member  12 . Receiving member  32  is affixed to adjusting member  12  by means of bolts  33 . With this structure, it is not necessary to form a concave spherical surface on adjusting member  12  and makes its machining easier.  
         [0048]     In case of  FIG. 8 , a cap  34  is place on a spherical member  26 ′ and allows the flat surface of cap  34  and block  27  to slide to each other. Cap  34  has a convex spherical surface that engages with the spherical surface of spherical member  26 ′. Spherical member  26 ′ is affixed to adjusting member  12  by means of bolts  33 . Spherical body  26 ′ is housed in adjusting member  12 .  
       EFFECTS OF THE INVENTION  
       [0049]     The invention makes a member that corresponds to a connecting rod unnecessary, so that it makes it possible to provide the slide at a higher position. This results in shortening the height of a mechanical press. On account of that, the rigidity in the vertical direction increases, and the rigidity in the horizontal direction increases as well. This also enables us to lower the ceiling height of the building where a mechanical press is stored and also results in the improvement of the press operation. In addition, the invention provides a mechanical press with a more stable performance and a longer longevity as adjusting member  12  is guided with a more rational guide.