Abstract:
A device for severing a bonding strip located between and securing together two rigid panels, one of which may be of glass. The device has a flat elongated blade intended, in use, to be inserted between the panels to sever the bonding strip. The device is provided with a rest mechanism adapted to sit on one of the panels being separated to guide reciprocation of the elongated blade, whereby the blade reciprocates in a direction parallel to the panel being separated.

Description:
FIELD OF THE INVENTION 
     The present invention relates to improvements in apparatus for removing windscreens or other similar panels from vehicle bodies or the like. The apparatus is intended to separate a bonding layer between the panel to be removed and the supporting frame work surrounding same. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 4,395,825 granted to Trevor S. Lock discloses apparatus of the aforementioned kind comprising a device for reciprocating a flat elongated flexible blade sharpened to one face along longitudinal edges and a curved end joining the longitudinal edges. The blade is reciprocated along the panel to be removed to separate the bonding layer. This type of apparatus has proved to be quite successful, particularly when used by skilled workmen, however, there are some problems when the apparatus is used by inexperienced workmen. These difficulties include, in some cases a difficulty in keeping the blade flat on the panel being removed and at the same time judging the depth of cut (reciprocation) required to separate the bonding layer without contacting and causing at least minor or superficial damage to the frame work surrounding the panel to be removed. Similarly, damage can occur to the panels themselves or coatings applied thereto. Further damage may occur to trim or other components on or surrounding the panel being removed. A still further problem is that if the blade is not held generally parallel to or flat on the panel, then a very poor or inefficient cutting operation results. 
     SUMMARY OF THE INVENTION 
     Objects of the present invention are therefore to provide improvements to apparatus of the type disclosed in the Lock Patent which will enable such apparatus to be used while at least minimising the aforementioned difficulties. It will of course be appreciated that the present invention is not limited to use with blades as defined in the Lock Patent but blades are clearly preferred. According to a first aspect, the present invention provides a device for severing a bonding strip interposed between and securing together overlapping portions of respective rigid elements, said device including a generally flat cutting blade portion shaped and arranged to, in use, engage the bonding strip between the overlapping portions in a cutting action to sever at least one of the overlapping portions from the bonding strip, and rest means adapted to engage the rigid element from which the bonding strip is being severed at a location spaced from the cutting blade portion to, in use, provide guidance for the movement of the cutting blade portion during said severing operation. 
     Conveniently, the cutting blade has a flat face on one side thereof defining a perimetal cutting edge and the opposite side is inclined upwardly from said cutting edge to provide support for the cutting edge. 
     In accordance with a second aspect, the present invention provides that, in use, the flat face is in contact with the rigid element from which the bonding strip is to be severed, and wherein the rest means is rigidably supported relative to the cutting blade to, in use, engage the rigid element from which the bonding strip is to be removed so that flat face of the cutting blade is in face to face contact with said rigid element. 
     In one preferred arrangement, the blade may be a generally flat elongated blade which is sharpened as disclosed in the Lock U.S. patent previously referred to. In another preferred arrangement, the blade may comprise any other form of blade known for this purpose including those which are oscillated during their cutting motion. 
     In one preferred arrangement, the panel removing blade may be a generally flat elongated blade which is sharpened as disclosed in Australian Patent No. 543405 and reciprocated in a cutting motion. In other preferred arrangements, the panel removing blade may comprise any other form of blade known for this purpose including those which are oscillated during their cutting motion. 
     In one preferred embodiment, the rest means may comprise a surface located in a plane generally parallel to a transverse dimension of the flat cutting blade portion. Alternatively, the rest means might be formed by two surfaces defining a plane generally parallel to a transverse dimension of the flat cutting blade portion. Conveniently, the plane of the or each said surface of the rest means is angled obliquely towards the flat cutting blade portion. 
     In a further preferred embodiment, the rest means may comprise an edge portion disposed generally parallel to a transverse dimension of the flat cutting blade portion. Alternatively, the rest means might be formed by at least two edge portions together defining a rest edge configuration disposed generally parallel to a transverse dimension of the flat cutting blade portion. 
     In a still further preferred embodiment, the rest means may comprise at least two point contacts defining a contact line extending therebetween disposed generally parallel to a transverse dimension of the flat cutting blade portion. 
     In a preferred arrangement, two said rest means are provided on diametrically opposed sides of the flat elongated panel removing blade. 
     The present invention also proposes providing, as a preferred feature, a stop element which is adapted, in use, to be located adjacent an end region of a flat elongated panel removing blade whereby the end region of the blade is positioned at a predetermined distance relative to the end zone of the stop element. Conveniently, the stop element is adjustable relative to the flat elongated panel removing blade to adjust the distance between the end of the blade and the end zone of the stop element. Preferably, the stop element is at least as transversely flexible as the blade. Normally, when a panel is being removed, the blade will extend beyond the end zone of the stop element but, for trimming purposes after a panel has been removed, the stop element may extend beyond the end zone of the blade. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Several preferred embodiments of the present invention will hereinafter be described with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a first embodiment of the present invention; 
     FIG. 2 is a partial perspective view showing a second possible embodiment of the present invention; 
     FIG. 3 is a partial perspective view showing a third possible embodiment of the present invention; 
     FIG. 4 is an exploded view of an alternative preferred guidance device adapted for connection to a panel removal tool; and 
     FIGS. 5,  6 ,  7  and  8  are side elevation views of preferred forms of panel removal tool according to the present invention shown in differing configurations of use. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 of the drawings shows an end of a tool  10  for reciprocating an elongated flat blade  11  in a direction indicated by arrow  12 . The tool  10  is conveniently actuated pneumatically but any other means of reciprocation could also be utilised. It will of course also be appreciated that a tool for oscillating a cutting blade could also be used. One preferred form of guidance cap  13  is shown secured to the end of the tool  10  by set screws  14 . In a possible alternative, the arrangement of the cap  13  may be integrally formed with the end of the tool  10 . The blade  11  passes through an end opening  28  in the guidance cap  13  and is secured by fastening means to the operating mechanism of the tool  10 . An access opening is provided through the cap  13  to permit access to the blade fastening means so that the blades can be replaced when desired. The blade  11  is conveniently sharpened at its end section  15  in a manner similar to that described in the Lock Patent such that there is a sharpened edge  16  located in a lower blade surface  17  of the blade. The guidance cap is conveniently formed with a block section  18  which includes at least one rest surface  19 . As shown in the drawing, the rest surface  19  is obliquely disposed such that it is angled towards the blade  11 . In this manner, in use, the rest surface  19  is placed in contact with the glass or other panel (such as a windscreen) and the blade  11  is thereby automatically located so that it will reciprocate in the plane of the panel being removed. Moreover, by angling the surface  19 , the blade end region  15  is directed towards contact with the panel being removed. It will of course be appreciated that the surface  19  could be replaced by two or more surfaces, by an edge as shown in FIG. 2 formed by one or more edge lines  26 , or by at least two point contacts  27  as shown in FIG. 3, each of which being arranged to maintain the blade  11  in contact with and parallel to the panel surface. It will further be appreciated that, if desired, the top surface  20  opposite to the surface  19  could also form a rest or guidance surface and in which case the blade  11  would be removed and inverted or turned over. This surface (or surfaces)  20  could also be obliquely formed similar to surface  19 . 
     The guidance cap  13  also includes a stop element  21  in the form of an elongated bar or strip having a first end  22  releasably held in the cap  13  by screw elements  23 . The stop element  21  is conveniently flexible longitudinally such that this element can flex as the blade  11  flexes. The opposed end  24  of the stop element defines a limit of depth of cut of the end region  15  of the blade  11 . The end  24  may be formed with a bent section  25  as illustrated but other arrangements could be utilised depending on the task required to be performed. To adjust the depth of cut, the screw elements  23  are loosened and the stop element  21  repositioned to define the desired distance between the element end  24  and the end  15  of the blade  11 . Thereafter, the screw elements  23  are re-tightened to fix the stop element  21  in position. 
     FIG. 4 illustrates an alternative preferred form of guidance cap  13  where like features have been given the same reference numbers as in FIG.  1 . In this embodiment, the stop elements are retained by a novel mechanism which allows quick and easy adjustment of the stop element  21  relative to the blade  11 . The cap  13  includes aligned cross bores  29  adapted to receive plug elements  30 ,  31 . Each of the plug elements  30 ,  31  has a non-circular cross-section thereby preventing rotation of same within the cross bores  29  so that the plug elements can move axially but not rotationally. Further, each plug element has a projecting ledge portion  32  adapted to project into the section  33  adapted to receive the stop element  21  such that the projecting ledge portions  32  will engage and hold the stop element  21 . In addition the section  33  is extended along the top of the guidance cap  13  to provide further rigidity of holding of the stop element  21 . Finally, a fastener bolt  34  is provided with a head  35  and a screw threaded section  36  opposite to the head. The bolt  34  passes freely through the internal bore  37  of the plug element  30  to be threadingly engaged with a threaded internal bore  38  of the second plug element  31 . Rotation of the bolt  34  in one direction will tend to move the plug elements  30 ,  31  apart to loosen their grip on the stop element  21  and rotation in an opposite direction will draw the plug elements  30 ,  31  together tightening their grip on the stop element  21 . Spring elements  39  are provided to maintain tension on the assembly preventing unwinding of the bolt  34  unintentionally during use of the device. As with the embodiment of FIG. 1, the guidance cap  13  also includes guidance rest surfaces  19 ,  20 . 
     Referring now to FIG. 5, a panel removal tool  10  is shown with a guidance cap  13  positioned with its guidance rest surface  19  against the windscreen panel  40  being removed. The stop element  21  has a free end zone that engages against the urethane seal  41  that is being cut by the blade  11  reciprocated along the surface of the panel  40 . It is apparent that this arrangement prevents the blade contacting and damaging structural parts of the vehicle frame around the panel  40 . FIG. 6 illustrates an arrangement similar to FIG. 5 except that in this case, a cowling  42  generally covers the urethane seal  41  being cut. In this case, a different form of stop element (similar to FIG. 1) is used where the end section  25  engages the cowling  42 . FIG. 7 is also an arrangement similar to FIG. 1 where the blade  11  and stop element  21  may reach a long way beyond a vehicle dashboard structure  43  or the like. FIG. 8 illustrates a still further arrangement where the stop element  21  engages the panel  40  being removed and the blade reciprocates along an end piece  44  on the stop element  21 . In this case the guidance surfaces  20  are maintained in contact with panel  40  being removed. Further, a portion of the urethane seal  45  may be left to be trimmed off later. 
     By the arrangements described, it is possible in a simple and convenient manner to maintain the blade  11  always parallel to the surface of the panel being removed and moreover to restrict the blade depth of cut to only that which is required to allow removal of the panel.