Abstract:
Improved slide lock apparatus used in bending apparatus to bend stock to an acute angle. A hydraulic cylinder with a ram extendable under hydraulic pressure provides the bending power. The ram automatically retracts a slide from an first outward location when hydraulic pressure is removed to a second inward location for two separate bends to achieve an acute angle bend. This improved slide lock prevents any possible injury to the operator by covering a stop arranged to prevent the slide from moving outward a greater distance then the first outward location.

Description:
[0001]    This is a continuation-in-part of application Ser. No. 11/671,543 filed Feb. 6, 2007, hereby incorporated by reference. 
       FIELD OF THE INVENTION 
       [0002]    This invention relates to an improved slide lock for apparatus which bends metal stock on the arc of a circle up to an acute angle of one hundred and eighty degrees by relocating the location of a slide to provide two locations relative to the die. 
       BACKGROUND OF THE INVENTION 
       [0003]    A large force is required to bend stock to an acute angle of one hundred and eighty degrees. Bending apparatus which requires such a large force uses a hydraulic cylinder with an extending ram. An extension of the ram transmits the force to apparatus which bears against the stock and bends it. An acute angle bend presents a problem compared to smaller bends because the force required is large and must be exerted over a long distance. This is difficult to achieve with a cylinder and ram because the long distance requires a long cylinder and ram which are both prone to buckling under such a large force. 
         [0004]    While a variety of metal stock benders are known in the art, the ability to bend stock to an acute 180 degree angle has only been provided by Mann et al. U.S. Pat. No. 2,656,872. Mann et al. utilizes a swinging frame which changes the angle and distance of the frame with respect to a forming die. This permits making a large bend by making smaller bends at each location. This apparatus is fairly complex and requires a substantial amount of shop space because of the size of the frame and the size of the arc. 
       SUMMARY OF THE INVENTION 
       [0005]    This invention is an improvement to the slide lock arrangement used in the parent case to secure the slide at two locations relative to the item being bent. This arrangement permits bending an acute angle in two steps with the force exerted on the bending arm being exerted first from an outer and then an inner location but with no intermediate set-up of the apparatus required. 
         [0006]    This process was accomplished in the parent application by a slide lock which used a pivotably mounted spring loaded clapper arranged to urge a gudgeon through an aligned hole in the slide against the slide bar. The slide bar had a hole sized and arranged to receive the gudgeon. The slide bar hole was aligned with the gudgeon when the slide was at a predetermined location inward from the stop. This permitted urging the gudgeon through the aligned hole and automatically locked the slide to the slide bar at that location. The clapper had a handle arranged to permit rotating the clapper and remove the gudgeon from the hole in the slide bar to manually unlock the slide from the slide bar. That arrangement provided an outer first and an inner second location for the cylinder and ram relative to the die. Since the full force of the cylinder could be exerted on the stop there was the potential for injury if the operator happened to have his hand or fingers in that area. 
         [0007]    This improvement to the parent application eliminates a potential danger to the operator in that a ramp along the slide bar extends upward from the outer to a point adjacent to the inner location. The outer end of the ramp provided a stop which engaged a gudgeon which extending downward from the slide. At the outer location the stop is covered by the slide and not accessible to the operator. Further, since the slide is moved manually from the inner to the outer position there is no possibility of injury. A hole adjacent to the opposite upper end of the ramp is sized to receive the gudgeon to automatically lock the slide at the inner location. Since the slide is drawn from the outer to the inner location by a spring, which retracts the cylinder extension for the second bend, there is no large force exerted between the gudgeon the hole which could injure the operator. This arrangement eliminates a possible hazard of the previous arrangement for securing the slide at the outer and inner locations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows a top view of one version of the improved slide lock arrangement attached to the bender apparatus; 
           [0009]      FIG. 2  shows the cross-section of the slide lock arrangement of  FIG. 1  with the slide positioned with respect to the slide bar locating the gudgeon within the hole in the slide bar; 
           [0010]      FIG. 3  shows the cross-section of the slide lock arrangement of  FIG. 1  with the slide positioned with respect to the slide bar locating the gudgeon at the upper edge of the ramp at the surface of the slide bar facing the slide; 
           [0011]      FIG. 4  shows the cross-section arrangement of  FIG. 1  with the slide positioned with respect to the slide bar locating the gudgeon between the innermost end of the ramp and the end of the channel opposite to the bending apparatus; 
           [0012]      FIG. 5  shows the cross-section arrangement of  FIG. 1  with the slide positioned with respect to the slide bar locating the gudgeon midway on the ramp using the second embodiment of the slide lock; and 
           [0013]      FIG. 6  shows the cross-section arrangement of the second embodiment of the slide lock with the slide positioned the same as  FIG. 2  with respect to the slide bar; 
           [0014]      FIG. 7  shows the cross-section arrangement of the second embodiment of the slide lock with the slide positioned the same as  FIG. 3  with respect to the slide bar; 
           [0015]      FIG. 8  shows the cross-section arrangement of the second embodiment of the slide lock with the slide positioned the same as  FIG. 4  with respect to the slide bar; and 
           [0016]      FIG. 9  shows the cross-section arrangement of the second embodiment of the slide lock with the slide positioned the same as  FIG. 4  with respect to the slide bar. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]      FIGS. 1-5  illustrate a first embodiment of the improved slide lock.  FIG. 1  shows slide  130  consisting of an upper side plate  130 A and a lower side plate  130 B slideably secured to each other on opposite sides of slide bar  128  by three bolts  130 AB extending through mating holes in the upper side plate and secured in mating threaded holes in the lower side plate. Arm  40  extending from the bending apparatus has an upper arm portion  40 A opposite lower arm portion  40 B which are connected together through spacers on opposite sides of slide bar  128  by bolts  40 C extending through mating holes in upper arm  40 A and secured in mating threaded holes in lower arm  40 B. 
         [0018]    Clapper  140  is pivotably mounted to the end of upper slide plate  130 A opposite arm  40  by bolt  140 A which extends through a coiled spring  140 A 2  into hole  140 A 1  which is sized large enough to enclose the spring and permit the clapper to incline with respect to upper slide plate  130 A which assists in rotating the end of clapper adjacent to arm  40  towards the upper slide plate  130 A. Bolt  140 B has its head recessed in slot  140 B 1  extending along clapper  140  terminating in a mating threaded hole in upper side plate  130 A to align clapper  140  with slide  130 . This arrangement is essentially identical in operation to that used with the first slide lock arrangement for pivoting clapper  140  except for the change in the end pivoted. A clapper handle  140 C is mounted on the end of clapper  140  by bolts  140 C 1  through mating holes in the handle secured in mating threaded holes in the clapper. In this improved slide lock arrangement, lifting the end of handle  140 C is used to rotate clapper  140  from a first angle parallel to upper slide plate  130 A to a second angle relative to the upper slide plate. The size of the second angle is described later. 
         [0019]      FIG. 2  shows clapper  140  parallel to upper slide plate  130 A with a gudgeon  140 D extending outward from the clapper through hole  130 C in upper slide plate  130 A and hole  128 A in slide bar  128  to the inner surface of lower slide plate  130 B. Slide bar  128  has a channel  128 B with an opening extending inward from the face of slide bar  128  opposite to clapper  140 , the opening being rectangular and the major dimension extending along the slide bar length. Channel  128 B has vertical sides extending inward toward the inner face of lower slide plate  130 B. The channel having a width along the length of slide bar  128  adequate to admit gudgeon  140 D. Channel  128 B has a planar surface facing the opening which forms planar ramp  128 C extending from the end closest to arm  40  which extends inwardly linearly from the surface of slide bar  128  adjacent to upper slide bar  130 A to a maximum depth near the surface of lower slide plate  130 B at a point offset an amount from the vertical end of the channel opposite to arm  40  to admit the end of gudgeon  140 D. As shown here slide  130  is at the second inner location with respect to arm  40  with slide  130  locked to slide bar  128  by gudgeon  140 D extending through holes  130 C and  128 A. This is the location of slide  130  relative to slide bar  128  when the second bend is made. 
         [0020]      FIG. 3  shows clapper  140  and gudgeon  140 D after being moved from the location shown in  FIG. 2  by manually lifting clapper  140  upward using handle  140 C to rotate the clapper from the first to the second angle with respect to upper slide plate  130 A. This lifts the inner end of gudgeon  140 D outward from hole  128 A in slide bar  128  and releases slide  130  from slide bar  128 . Handle  140 C is then used to manually translate slide  130  to the location shown in  FIG. 3 . 
         [0021]      FIG. 4  shows slide  130  after being moved manually by handle  140 C along slide bar  128  from the location shown in  FIG. 3  to the outer first location relative to arm  40 . Here the full length of gudgeon  140 D bears against the vertical end wall of channel  128  opposite to arm  40 . This provides at sturdy stop at this first location of slide  130  relative to slide bar  128  and prevents the slide from moving a greater distance from arm  40 . This first location is the location of slide  150  when the first bend is made. 
         [0022]      FIG. 5  shows gudgeon  140 D midway on ramp  128 C from the location shown in  FIG. 4 . This results after the first bend has been made and pressure is removed from cylinder  42  allowing its ram to retract. As described for the previous slide lock arrangement, the retraction of the ram of cylinder  42  will pull slide  130  from position one toward position two which here has positioned gudgeon  140 D midway on ramp  128 C and rotated clapper  140  between the first and the second angle. When the ram of cylinder  42  is fully retracted slide  130  will be at the position shown in  FIG. 2  with gudgeon  140 D locking slide  130  to slide bar  128  as described earlier. When slide  130  is locked to slide bar  128  the bending apparatus is arranged to make the second bend as described earlier. 
         [0023]      FIGS. 6-9  show clapper  140 - 1 , gudgeon  140 - 1 D with an end  140 - 2 D, a slide  130 - 1 , slide bar  128 - 1 , slide bar channel  128 - 1 B with a ramp  128 - 1 C. These figures show a second embodiment of the improved slide lock the following changes: ramp  128 - 1 C extends completely across slide bar  128 - 1  channel  128 - 1 B to the end opposite to arm  40  rather than terminating a distance offset therefrom and gudgeon  140 - 1 D has an end  140 - 2 D with an incline which matches the incline of ramp  128 - 1 C. With these arrangement the side of gudgeon  140 - 1 D again bears against the entire vertical end wall of channel  128 - 1 B opposite to arm  40  even through the ramp is changed in shape. This also provides at sturdy stop at this first location of slide  130 - 1  relative to slide bar  128 - 1 . The operation of the first and second embodiments of the two slide locks are identical and the discussions of:  FIG. 2  applies to  FIG. 6 ,  FIG. 3  applies to  FIG. 7 ,  FIG. 4  applies to  FIG. 8  and  FIG. 5  applies to  FIG. 9 . 
         [0024]    The previous slide lock arrangement was accomplished by the end of the slide itself bearing against a barrier. This previous arrangement presented a danger in that this area was exposed and the operator could place a hand or finger between these two parts. Since a large outward force is applied against the stop during the first bend this could result in serious injury. In this improved slide lock arrangement the stop is located under slide  130  which is not accessible to the operator and eliminates this danger. 
         [0025]    There are undoubtedly a number of other arrangements which will rotate clapper  140  from the first to the second angle as slide  130  translates from the first to the second location, as illustrated by the two embodiments described here. It will be understood therefore that this disclosure, in many respects, is only illustrative. Changes may be made in details, shape, size, material, and arrangement of parts can also be made without exceeding the scope of the invention. Accordingly, the scope of the invention is as defined in the language of the appended claims.