Patent Publication Number: US-4254651-A

Title: Device for bending metal objects

Description:
FIELD OF THE INVENTION 
     Generally this invention concerns devices and methods for working of metal objects and especially to devices commonly used for the bending of pipe, tube, rod, bars and similar elongate members, and more particularly to portable devices of this kind capable of use on a job site. The invention also includes objects when bent by the device of this invention. 
     BACKGROUND OF THE PRIOR ART 
     Bending and like devices are well known and generally comprise an elongate frame having an arm transverse thereto. A hydraulic ram is fitted lengthwise to the frame and has a die or former mounted on the end of the piston rod. On extension of the ram, the former pushes against a workpiece, the sides of which are held by stops mounted on the arm, to form a bend therein. In practice these prior devices suffer certain disadvantages--thus if it is required to bend a workpiece adjacent an already bent section, the end of the latter section tends to strike the frame and interfere with the bending process. Additionally, a problem with a number of prior devices is that the stops have to be removed in order to free the workpiece and/or even to initially fit the workpiece before bending. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of this invention to provide a bending machine for pipe, rod or the like, which does not suffer from the above disadvantages. In fact, the device is capable of bending workpieces in such a way that two or more adjacent or successive bends can be made therein such that said bends lie in different planes. This is achieved because the end of one bend does not strike the frame during forming of an adjacent bend. Thus the device of this invention has particular utility in the construction of roof racks and bull bars and crash bars for motor vehicles, and in general plumbing and vehicle maintenance. 
     Thus according to this invention, a device for bending pipe or the like elongate workpieces comprises an elongated frame, an arm fixed to said frame and extending laterally to both sides thereof, a pair of laterally spaced stop members mounted on said arm, motivating means fixed to said frame having a relatively moveable part for extending and retracting lengthwise of said frame, a link connected at one end to said relatively moveable part and extending lengthwise of said frame past said arm, and a former mounted on the end of said link remote from said relatively moveable part, the arrangement being such that on extension of said relatively moveable part, said former moves towards said arm, whereby to bend a workpiece held between said former and said stop members. 
    
    
     BRIEF DESCRIPTION OF THE VARIOUS FIGURES 
     The invention will be better understood by reference to the accompanying drawings, in which 
     FIG. 1 is a side elevation schematically showing one form of the device of this invention, 
     FIG. 2 is a schematic illustration of a basic component layout thereof, showing a &#34;workpiece&#34;, 
     FIG. 3 is a plan view of the device of FIG. 1, and 
     FIG. 4 is an end view of the device as seen from the former end. 
    
    
     DETAILED DESCRIPTION 
     In the embodiment illustrated, frame 1 supports hydraulic ram 2 by pin 8 in upright members (only one visible) 3b. A pair of arms 3 are rigidly fixed transversely to frame 1, one above the other. The top arm is supported by struts 3a which in turn are attached to frame 1 by uprights 3b. A pair of stops 4 are detachably held between arms 3 by pins 4a. Pins 4a fit in holes 5 in arms 3 and stops 4 can be variably spaced by suitable selection of holes 5. The former 6 is connected via linkage 7 to the end of the piston rod of the ram by pin 8a. Former 6, which has a free upper end (not connected to or overlapped by frame 1 or arms 3), is detachably mounted at its bottom or lower end on linkage 7 whereby various formers for different purposes may be fitted to the device. 
     In operation, the workpiece is set between former 6 and stops 4, and when the ram is extended, it is bent so that the peak of the bend faces the ram (see left half of FIG. 2). It should be noted that this is basically a &#34;pulling&#34; operation, whereas that of the prior devices is a &#34;pushing&#34; operation, in which the peak of the bend faces away from the ram. Consequently, since the ends of the workpiece bent by the device of the present invention move away from the frame during bending, any bends already present, and adjacent to the present operation, do not strike the frame, as they would in prior devices. Further, having regard to the illustrations it can be seen that (once the ram is retracted) the workpiece simply comes away from the stops, whereas in prior art devices this is not the case, and further, unless the workpiece is short enough to be removed laterally of the frame, the stops have first to be removed to free the workpiece, since it will be trapped in the frame between the stops and the ram. This is a time consuming process and reduces the rate of work and operator output. 
     Since the workpiece is positioned between the former and the ram, obviously the piston rod does not connect directly to the former. As shown in the illustrations, the link 7 has a horizontal portion running in the frame (see FIG. 4) and a pair of upright portions (9, 9a) at either end, one (9) connected to former 6, and the other (9a) connected to the piston rod via pin 8a. These upright portions run in slots in the frame 1, clearly visible in FIG. 1. 
     It will be obvious to the man skilled in the art that ram 2 could be fixed to the frame at 8a and to the link 7 at 8 instead of the reverse situation as illustrated; in this case the ram would have to be double acting since the bending would be done on the retraction stroke. Similarly, the ram can be hand pumped, or arranged to be connected to any suitable power source, e.g. the hydraulic system of a tractor. Additionally, instead of a hydraulic ram, it will be appreciated that a screw device or in fact any linear motivator can be used. Various other components of a conventional nature such as a calibrated scale may be added if desired if repetitious work is involved. 
     Whilst the foregoing description has referred to certain uses, e.g. pipe bending, to which the invention may be put, other uses are possible where metal articles require bending or deforming. 
     Bearing in mind the above comments, it is to be understood that the foregoing description is by way of example only, and the scope of the protection sought is to be limited only by the scope of the appended claims.