Process and device for copying and threading in automatic square cycle

Device for copying and thread cutting in automatic square cycle, comprising:

• a longitudinal carriage;
• a cross slide having a bottom swivelling support and being attached to said longitudinal carriage;
• a copy carriage having an upper face, a corner, and being mounted to said bottom swivelling support of said cross slide;
• an upper swivelling support being fixed to said upper face of said copy carriage;
• a tool and a tool holder;
• a longitudinal support for said tool being equipped with said tool holder and being attached on said upper swivelling support;
• a movable first arm having a free end and being fixed at said corner of said copy carriage;
• a head being equipped with a copy valve having a stylus and an assembly mounting templates with two templates, one for cutting and the outer for threading, which templates are not rigidly supported to a bed and control movements of said longitudinal carriage;
• a variable speed motor arranged to move said templates;
• a programming panel;
• a hydraulic unit being mounted on said longitudinal carriage;
• a first set of time relays being mounted on said programming panel;
• a first set of electric switches for programming said first set of time relays of the automatic feed system for depth of cut when in copying cycle and being mounted on said programming panel;
• a second set of time relays being mounted on said programming panel;
• a second set of electric switches for programming said second set of time relays of the automatic feed system for depth of cut when in thread cutting cycle and being mounted on said Programming panel;
• and a control panel containing an electric selecting switching for pre-positioning of copy and thread cutting automatic cycles and a button for starting the automatic cycle.

Process for copying and threading in automatic square cycle, applicable to and/or incorporated into engine lathes in general, comprising the steps of material removing machining of parts by a copying method in automatic square cycle;

• providing during said machining step an automatic feed system for depth of cut with programmable and progressive increments through electric means;
• cutting of threads on a surface of the machined parts in automatic square cycle;
• providing during said cutting step an automatic feed system for depth of cut with programmable and progressive increments through electric means;
• pressing a starting electric button;
• rotating a main spindle and simultaneously moving a tool carriage from a starting or resting position at rapid traverse towards a workpiece impelled by oil that enters a chamber of a carriage hydraulic cylinder, until a stylus touches template profile;
• touching by the stylus of template profile and activating a copying valve piston, and taking by the copying valve piston when actuated a position that it distributes oil to two hydraulic cylinder chambers in quantity and pressure proportional to the areas of a cylinder and piston of said hydraulic cylinder in such a way to maintain the system balanced and to stop cross travel of the tool carriage at a start of cutting;
• moving a longitudinal carriage at slow working travel towards the workpiece with the cross travel of the tool carriage and longitudinal travel of the longitudinal carriage;
• starting the tool edge from the resting or starting point and traveling to start cutting;
• at this point interrupting cross travel of the tool carriage by contact of the stylus on the template profile;
• continuing moving the longitudinal carriage performing the path required for machining the workpiece;
• exploring during the path of the longitudinal carriage by the stylus the template profile and actuating with its movement the copying valve piston which controls oil flow in the two hydraulic cylinder chambers imposing a cross movement to the tool carriage;
• following by the cross movements of the tool carriage the shape of the template profile which profile is reproduced on the workpiece by the tool;
• reaching by longitudinal carriage the end of machining and therefore actuating a travel limit electric switch which energizes a solenoid which controls the valve for returning tool carriage cross movement in the opposite direction;
• withdrawing from the workpiece;
• actuating by the tool carriage upon returning at a certain point another travel limit electric switch which controls the reverse of the feed rod of longitudinal carriage at rapid traverse moving longitudinal carriage from end of machining towards the resting or starting point;
• actuating, when longitudinal carriage reaches the starting point, another travel limit electric switch which actuates simultaneously the electric switch that starts an electric motor that turns a screw that imposes movement to the template support through a nut coupled to this screw;
• controlling the electric switch the motor by an electric programming system consisting of selecting switch and time relays so that injecting electric current under controlled intensity by the motor and for a determined time the screw turns only a fraction and imposes a limited displacement to the template support as previously adjusted in the program system, with the template displacement the stylus taking a position on space which is different from the previous one and this resulting in a new position for the tool carriage when the stylus touches again the template profile, this displacement being increment of cut and corresponding to the depth of cut with which the tool must machine in the next pass, the start of the cross carriage towards the workpiece to be machined, the start of the longitudinal carriage towards the workpiece to be machined, being these movements successively repeated until the cross carriage reaches the programmed point as being the last pass and at this point it actuating another end of travel electric switch which is programmed for stopping the machine after the tool has performed the whole machining path and returned to the starting or resting point, upon completing the copying cycle, programming must be selected for the thread cutting cycle, so that the electric selecting switch is turned to position of thread cutting disengage carriage mechanical travel by positioning control lever in neutral, position lever for disengaging leadscrew nut in the engaged position, position thread box levers in accordance with the desired thread pitch, and turn square tool post to position thread cutting tool.

Device for copying and thread cutting in automatic square cycle, comprising a longitudinal carriage;

• a cross slide having a bottom swivelling support and being attached to said longitudinal carriage;
• a copy carriage having an upper face, a corner, and being mounted to said bottom swivelling support of said cross slide;
• an upper swivelling support being fixed to said upper face of said copy carriage;
• a tool and a tool holder;
• a longitudinal support for said tool being equipped with said tool holder and being attached on said upper swivelling support;
• a movable first arm having a free end and being fixed at said corner of said copy carriage;
• a head being equipped with a copy valve having a stylus and an assembly mounting templates;
• a programming panel;
• a hydraulic unit being mounted on said longitudinal carriage;
• a first set of time relays being mounted on said programming panel;
• a first set of electric switches for programming said first set of time relays of the automatic feed system for depth of cut when in copy cycle and being mounted on said programming panel;
• a second set of time relays being mounted on said programming tool;
• a second set of electric switches for programming said second set of time relays of the automatic feed system for depth of cut when in thread cutting cycle and being mounted on said programming tool;
• and a control panel containing an electric selecting switch for pre-positioning of copy and thread cutting automatic cycles and a bottom for starting the automatic cycle, said assembly mounting templates comprising a base guided on a main guideway of the lathe bed, a first support being slidable on first guideways on said base, said guideways being at right angle to the lathe bed prism and which can be of metal to metal contract or provided with anti-friction linear bearings, the displacement of said first support being servo-assisted through an electric motor fixed on said base with a shaft of said motor connected to a worm and a worm wheel having a guide screw which coupled to a nut which in turn is connected to an arm through a bushing, said arm mounted on said first support being slidable in relation to said base when rotating movement is impelled to said motor, a second support being slidable on second guideways positioned on an upper face of said first support, said second guideways being parallel to the displacement of said first support said first support being provided with a first knob and first dial mounted together on a first screw through a first key, and a second screw being coupled to a first thread existing on the body of said first support and on the other side supported by a first bearing, which in its turn is mounted on said second support through third screws, while a third support being slidable on third guideways being disposed on the upper face of said second support positioned at right angle to the direction of displacement of said support which is provided with a second knob and a second dial, which is jointly mounted on a fourth screw through a second key and a fifth screw, said fourth screw being coupled on one of its end to a second thread on the body of said third support and on the other end rested on a second bearing which is connected to said second support through sixth screws.