Abstract:
A bracing device for a bending machine, in particular for a tube bending machine, in the form of a slide rail moved linearly in slaved fashion in the bending operation and having a plurality of slide rail extensions for different bending radii, which are mounted on the slide rail ( 12 ) via lockable and unlockable adapters.

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 09/787,728 filed on May 29, 2001, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a bracing device for a bending machine, in particular for a tube bending machine, in form of a slide rail, moved linearly in slaved fashion in the bending operation, with a plurality of slide rail extensions for different bending radii. 
     Since in bending machines with a bracing device of the type defined at the outset, all the slide rail extensions move simultaneously, these bending machines have the disadvantage that when relatively large radii are being bent, the slide rail extension for a smaller radius can collide with tool parts, such as a clamping jaw, for the small radius if the radii differ accordingly from one another. Until now, this problem has been solved by using bracing rollers instead of slide rails. For demanding bending tasks, such as bending of very thin-walled tubes or very soft tubes or bending very small radii, however, bracing rollers are no longer suitable. Then the use of slide rails is absolutely required. 
     U.S. Pat. No. 5,042,979 discloses a bending machine with several bend dyes have different diameters and movable in a horizontal direction and in a vertical direction so as to bend a tube at different curvatures. The pressure dyes are not movable axially to the tube or parallel to the axis of the tube, and also the pressure dyes are not removably attached via a adaptors. Also, the problem of a collision of the pressure dyes with clamping jaws is not mentioned in this patent. 
     U.S. Pat. No. 4,130,004 discloses a tube bending machine with only one pressure dye which does not show different slide rail extensions, and therefore the problem of collision between slide rail extensions and clamping jaw or the like does not occur in this bending machine. The removable attachment of the pressure dye to the slide in this machine is not used to avoid collision between the pressure dye and clamping jaws, since at the engine of such collision does not exist. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to improve a bracing device for a bending machine of the type defined at the outset in such a way that the risk of collision between slide rail extensions and tool parts is avoided. 
     The invention attains this stated object with a bracing device of the type defined at the outset, in that the slide rail extensions are mounted on the slide rail via lockable and unlockable adapters and the locking and unlocking of the adaptors is programmable via an MC controller. In this way, when relatively large radii are being bent, the slide rail extensions and in particular those for the small radii can preferably be decoupled from the common drive of the slide rail extensions, thus averting collision of the slide rail extensions, and especially those for the small radii, with clamping jaws or other tool parts. 
     With a view to comfortable machine operation, the adapters can be programmable via an NC controller or can be locked and unlocked. 
     To make it possible for bending machines without an adapter according to the invention to be retrofitted with an adapter, the slide rail extensions and the adapter can form a retrofitting unit. 
     To enable to plurality of slide rail extensions to be aligned with the height of the plurality of bending tools, the plurality of slide rail extensions and the adapter can be separately adjustable in height. 
     The invention also relates to a bending machine, in particular a tube bending machine, having a clamping device for a workpiece, in particular a tube to be bent, a bending head provided with a plurality of bending tools that have different radii, and a pivot arm that has a plurality of clamping jaws that can be moved horizontally and/or vertically to the longitudinal axis of the workpiece and that cooperate with the bending tools, characterized in that it has a bracing device according to the invention. 
     One exemplary embodiment of a bending machine embodied according to the invention will be described in further detail below in conjunction with the accompanying drawing. 
     The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1, a schematic view of a bending machine with a bracing device of the invention; 
     FIG. 2, a side view of the bracing device of the bending machine of FIG. 1; 
     FIG. 3, a view from above of a slide rail with four levels of slide rails; 
     FIG. 4, a cylinder for movement of the tube in the longitudinal direction; 
     FIG. 5, one form of a locking device for the present invention; and 
     FIG. 6, the locking devices as adapters. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a bending machine  10  with a machine body  16  and a bending head  17 . A tube to be bent, not shown in further detail, can be fastened in a clamping device  11 . A slide rail  12  has the task of bracing and guiding the tube during the bending operation. On the front end of the slide rail  12 , there are slide rail extensions  20 ,  22 ,  23 ,  24  (FIG.  2 ). The traveling motion of the slide rail  12  during the bending operation must be effected synchronously with the bending motion of a clamping block  13  that has clamping jaws  18  and is mounted on a pivot arm  14 . In the bending operation, the tube is bent via a suitable bending tool  15 . 
     FIG. 2 shows the slide rail  12  of FIG. 1 in an enlarged view; the four slide rail extensions  20 ,  22 ,  23 ,  24  are mounted lockably and unlockably on it via adapters  21 . For the sake of convenient handling, the locking and unlocking can be done via the NC controller of the machine or automatically. 
     By means of the locking and unlocking, primarily when relatively large radii are being bent, the slide rail extension  20  for smaller bending radii can be decoupled from the slide rail. In this way, a collision between the slide rail extension  20  and the clamping jaws  18  shown in FIG. 1 can be avoided. 
     FIG. 3 shows a top view of a slide rail  1  with four levels of slide rails  2 . Each level  2  has a slide  3  on which a slide rail extension  4  can be mounted. The slides are movable along a rail  5  in longitudinal direction of the tube. Each slide  3  has a locking device  6  used to connect the slides  3  with a main slide  7 . The main slide  7  is moved in longitudinal direction of the tube by a cylinder  8 , as shown in FIG.  4 . 
     Numerous possibilities exist for automatically locking and unlocking two elements, as will be appreciated by one skilled in the art. For example, the adapters can be provided with pins or bolts that are insertable into grooves or holes of the slide rail. The insertion of the pins or bolts can be carried out via pneumatic cylinder or to be motor driven. Instead of a linear movement of bolts or pins, also a rotational movement of a locking element, like a key or the like, can be carried out in order to lock and unlock the adapters. 
     FIGS. 5 and 6 show how the locking devices  6  operate. The locking device  6  has a cylinder  10 , which moves and removes a pin  11  from a hole  12 . In FIG. 5, the pin  11  is inserted into the hole  12 . The slide  3  is now locked to the main slide  7 . 
     In FIG. 4, the cylinder  10  has the pin  11  removed from the hole  12 . The slide  3  and the main slide  7  are now disconnected. The locking devices in this embodiment are the adapters. 
     FIGS. 5 and 6 show the locking devices  6  of the adapters. The locking devices have pneumatic cylinders  10  which moves pins  11  into holes  12  and also remove the pins  11  from the holes  12 . In FIG. 5, the pin  11  is inserted into the hole  12 . The slide  3  is now locked to the main slide  7 . Each of the cylinders  19  has a valve V which is connected with the computer C controlling the function of the whole machine. The valves open and closed electrically, or in other words in an NC programmable manner. 
     Naturally, a separately movable slide rail  12  can be provided for each slide rail extension  20 ,  22 ,  23 ,  24 . However, this would mean considerable additional expense for control, drive and measurement devices. 
     It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above. 
     While the invention has been illustrated and described as embodied in bracing device for a bending machine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 
     What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.