Abstract:
The invention relates to an oxy-fuel torch. The torch comprises a body ( 10 ) comprising a number of pipes for conveying at least two streams of gas between inlets ( 14, 15 ) and outlets; at least two valves ( 16, 20, 22 ) mounted in said body capable of adopting a closed rest position and an open active position; a single control ( 12 ) for said valves and mounted so that it can move on the body and able to be moved so that it collaborates with said valves, capable of adopting a first stable position in which all the valves are at rest and at least one second stable position in which at least one of the valves is in the active position; controllable means ( 40 ) of locking said control ( 12 ) so as to secure it, at rest, to said body; and at least one controllable delivery adjusting means ( 46, 48 ) mounted on said body for adjusting the delivery of at least one of said streams of gas.

Description:
BACKGROUND OF THE INVENTION 
     The subject of the present invention is an oxy-fuel torch and, more particularly, a system for controlling such a torch comprising at least three or four valves, and a single control for said valves collaborating with these and capable of adopting a first position in which said valves are at rest and a second stable position in which at least one of said valves is in the active position. 
     DESCRIPTION OF THE PRIOR ART 
     In the known way, oxy-fuel torches can be classified into three categories according to their use. 
     There are torches for cutting, also known as “flame cutters” which, on the one hand, use a fuel gas such as C 2 H 2  and, on the other hand, use oxygen as oxidizing agent. In these torches, it is necessary to supply gas to the pilot flame, when they have one, and to mix the gases to produce the heating flame and finally to provide a separate supply of oxygen to obtain the cutting jet. 
     In another category, in the case of heating or welding torches, also known as “blow torches” or “welding torches”, respectively, all that is required is for the fuel, for example acetylene, to be mixed with oxygen to supply the main flame and supply the pilot flame. 
     However, in both instances, it is necessary, during the various stages of use (igniting the pilot, igniting the heating flame, possibly producing the cutting jet, extinguishing the main flame), to check the rate of delivery of the fuel and of the oxidizing agent so as to obtain the respective characteristics of heating, welding or cutting as desired, and to synchronize the successive phases of supplying the two gases, namely fuel and oxidizing agent. 
     In conventional torches, the control for opening and closing the supply of the two gases and for adjusting the delivery of these two gases is achieved using different controls. 
     In order to overcome these drawbacks, it has already been proposed for the controls for the supply of the two gases to be combined, for example as in the case of the torch described in document FR-A-2695458. 
     It has also been proposed for torches to be supplied that comprise a single device for controlling the gases and for ignition. A device such as this is described, for example, in document FR-A-2731266 or DE-A-2326125. 
     Other torches or control systems for torches are also described in the documents: U.S. Pat. Nos. 5,470,227, 5,792,281, EP-A-0895026 or FR-A-2770657. 
     However, in the case of the torches disclosed in these documents, while the technical arrangements described therein can sometimes lead to an improvement in the efficiency or operation of the torch in question, they do present certain drawbacks, and, in particular, in the case of some of them, that of encouraging incorrect use or inadvertent triggering. 
     Specifically, it can happen that the torch falls onto its control button or alternatively that, on a work site for example, the torch supply hoses become caught up in plant and that the torch, thus dragged along the ground, butts up against an obstacle, causing it to be unintentionally lit or causing the gases to be inadvertently switched on. 
     It can also happen that someone inexperienced attempts to extinguish a lit torch and incorrectly shuts the valves, allowing gas to leak or causing flashback. 
     Furthermore, it is also necessary to be able to adjust the delivery of fuel gas and the delivery of oxidizing gas delivered by the torch accurately. 
     In addition, it is also advantageous to be able to perform all or some of these adjustments during an initial phase and then to keep these adjustments for later use, that is to say after the torch has been put out a number of times. This is because such a possibility of preserving the settings makes it easier to carry out ignition to start with and avoids the phenomena of popping, the emission of smoke at the time of ignition and/or flaring. 
     With this as a starting point, one object of the present invention is therefore to provide an oxy-fuel torch which makes controlling the supply of gas to the torch simpler and safer and which allows the delivery settings for the oxidizing gas, such as the oxygen, and for the fuel gas, such as acetylene, to be memorized. 
     SUMMARY OF THE INVENTION 
     The solution of the invention is therefore a torch, particularly of the oxy-fuel type, comprising: 
     a body comprising a number of gas pipes for conveying at least two streams of gas between a number of inlets and a number of outlets; 
     at least two valves mounted in said body and capable of adopting a rest position in which the corresponding stream of gas is interrupted in at least one of said gas pipes and an active position in which the passage of the stream of gas is allowed through at least one of said gas pipes; 
     a single control for at least said two valves and mounted so that it can move on said body and able to be moved in a path so that it collaborates with at least said valves, said control being capable of adopting a first stable position in which said two valves are at rest and at least one second stable position in which at least one of said valves is in an active position; 
     controllable means of locking said control so as to secure, at rest, said control to said body, at least in said first position, and which can be actuated by hand to free said control from said body; and 
     at least one controllable delivery adjusting means mounted on said body for adjusting the delivery of at least one of said streams of gas, said adjusting means comprising a mobile control element. 
     Depending on the case, the torch of the invention may comprise one or more of the following features: 
     said control for said valves can be moved in translation in the direction of a longitudinal axis of said body; 
     it comprises an ignition system of the piezo-electric type; 
     it comprises two delivery adjusting means, each adjusting means being associated with one gas, particularly with oxygen, on the one hand, and with a fuel gas, such as acetylene, on the other hand; 
     the mobile control element is a rotary handwheel, preferably a rotary handwheel the position of which is indicative of the gas delivery adjusted; 
     each adjusting means comprises a tap comprising a tap body, a moving needle and a seat, and a handwheel being mounted so that it can rotate on said tap body so as to cause said needle to move; 
     at its active end, the needle comprises a delivery-adjusting axial portion and an annular sealing surface, said seat comprising an axial passage equipped with a zone with a progressive profile capable of collaborating with the adjusting portion of the needle so as to adjust the delivery of gas and an annular sealing rib surrounding said axial passage and capable of collaborating with said sealing surface when said needle is brought into its closed position; 
     each valve comprises a seat and a mobile shutter equipped with a control stem which has a control end, and said control comprises a slider external to the body of said torch and a cam secured to said slider, said cam being capable of collaborating or of not collaborating with the control end of the control stems of said valves according to the position of said slider; 
     said locking means comprises a push-button mounted so that it can move with respect to said slider and capable of adopting a rest position in which said slider is secured to the body of the torch and an active position in which said slider is free with respect to said body; 
     it comprises at least three valves, preferably at least four valves. 
     it comprises a first valve for controlling the fuel gas to deliver a pilot flame; a second and third valve for, respectively, controlling the main flame fuel gas and for controlling the main flame oxygen, the second valve also, on a branch, supplying the pilot flame ignition system; and a fourth valve for controlling the oxygen for the cutting jet. Said first, second and third valves are on/off valves and said fourth valve can be adjusted progressively. This version of torch is recommended for cutting a piece in which one of the gases is oxygen and the other gas is a fuel, said torch delivering a pilot flame, a main heating flame and a cutting jet; 
     it comprises means for defining a second stable position of said control in which position said first and fourth valves are in the rest position and the second and third valves are in the active position; it preferably also comprises means for defining a third stable position in which said second, third and fourth valves are in the active position and the first valve is in the rest position. Said third stable position of the slider corresponds to the second end of its path and said locking means adopts its rest position when said slider is in its first stable position at a first end of its path and when said slider is in its third stable position corresponding to the second end of its path; 
     as an alternative, it comprises a first valve for controlling the fuel for the pilot; a second valve for controlling the fuel for the heating flame; a third valve for controlling a system for igniting the pilot flame; and a fourth valve for controlling the oxygen for the heating flame; said valves preferably being of the on/off type. This version of the torch is preferred for heating a piece in which one of the gases is oxygen and the other gas is a fuel, said torch delivering a pilot flame and a main heating flame, said pilot flame being brought about by operating the ignition system. It comprises means for defining said second stable position of the control and, in this position, said second and fourth valves are in the active position and said first and third valves are at rest; 
     according to another alternative form, it comprises a first valve for supplying the main flame with oxygen; a second valve for supplying the main flame with fuel; and a third valve for supplying the pilot with fuel; said three valves preferably being of the on/off type. This version is preferred when two pieces are to be welded and one of the gases is oxygen and the other is a fuel gas, said torch delivering a pilot flame and a main welding flame. 
     More generally, the invention also relates to a torch comprising: 
     a body comprising a number of gas pipes; 
     at least two valves mounted in said body and capable of adopting a rest position in which the corresponding stream of gas is interrupted in at least one of said gas pipes and an active position in which the passage of the stream of gas is allowed through at least one of said gas pipes; 
     a single control for at least said two valves and mounted so that it can move on said body, collaborating with at least said valves and capable of adopting a first stable position in which said valves are at rest and at least one second stable position in which at least one of said valves is in the active position; and 
     at least one delivery adjusting means comprising a mobile control element and controllable so as to adjust the delivery of at least one of said streams of gas. 
     there are preferably two delivery adjusting means which are associated with each of the two gases consisting, respectively, of the oxidizing gas, such as oxygen, and the fuel gas, such as acetylene. Each adjusting means comprises a mobile control consisting of a rotary handwheel the angular position of which is indicative of the gas delivery in the gas pipe in question. 
     Using the torch of the invention, the implementation of the various phases of supply to the torch, whether it is a cutting, heating or welding torch, is carried out by actuating one single control and, in addition, this control is preferably equipped with a device for locking in at least the “off” position, thus avoiding accidental supply to the torch. 
     It will also be understood that by virtue of the presence of the one or more means for adjusting the delivery of at least one of the gases distinct from the torch gas supply valves, the various settings can be memorized and/or preserved even after the torch has been extinguished. 
     Furthermore, this separation between the controls by valves which may be of the on/off type, and the delivery adjusting members makes it possible to make the delivery adjusting means far more effective and accurate. 
     In the context of the present invention, the words “gas pipe” are used to denote any duct, line or passage or any other gas circuit formed in the body of the torch and allowing the various streams of gas to be transported within said torch body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the invention will become better apparent from reading the description which follows of a number of embodiments of the invention which are given by way of nonlimiting examples with reference to the appended figures in which: 
     FIG. 1 is a view in vertical section of the body of a cutting torch, also known as a “flame cutter”; 
     FIG. 2 is a view from above of the body of the torch of FIG. 1, the control being omitted; 
     FIG. 3 is a view from the left of the body of the torch of FIG. 1; 
     FIG. 4 is a view in vertical section of a delivery adjusting tap that can be used in the torch of FIG. 1; 
     FIG. 5 is a diagrammatic view showing the various positions of the control for the torch of FIG. 1; 
     FIG. 6 is a vertical section of a body of a heating torch; 
     FIG. 7 is a partial view from above of the torch of FIG. 6, the control adjusters being omitted; and 
     FIG. 8 is a partial view in vertical section of a body of a welding torch. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring first of all to FIGS. 1 to  3 , one embodiment of a cutting torch according to the invention will be described. 
     These figures depict the body  10  of the torch on which a single control  12  is mounted so that it can slide. The torch body comprises a fuel gas inlet  14  and an oxygen inlet  15  or inlet for any other oxidizing gas. The control of the supply of the two gases for supplying the pilot, the main flame and the cutting jet is obtained using four valves which are best visible in FIG. 2, mounted on gas pipes pierced in the body  10  and connecting the gas inlets  14  and  15  to the cutting oxygen outlet  17 , heating oxygen outlet  19 , heating fuel outlet  21  and pilot fuel outlet  23  (cf. FIG.  3 ). There is a first valve  16  for controlling the fuel supply to the pilot, a second valve  18  for controlling the main flame fuel, a third valve  20  for controlling the oxygen in the heating flame and for activating the ignition system  25  of the pilot which is of the piezo-electric type, and a fourth valve  22  for controlling the oxygen to create the cutting jet. 
     In the embodiment considered, the values  18  and  20  are arranged in one and the same plane orthogonal to the axis XX′ of the torch body. The valves  16 ,  18  and  20  are of the on/off type. Each of these valves comprises a seat  27  and a moving shutter  24  mounted so that it can move in a bore  29  made in the body of the torch. The shutter  24  is extended by a control stem  26  comprising a control head  28 . The control heads  28  of the valves  16  to  22  in their rest position depicted in the figures, project out of the upper face  10   a  of the torch body. In their rest position depicted in FIG. 1, the valves  16  to  20  are in the closed position. Synchronized control of the various valves  16  to  22  is provided via the single control  12  which is mounted so that it can move in translation in the translation of the axis XX′ of the body of the torch via a guide piece  30  itself secured to the upper face  10   a  of the body  10  of the torch. The guide piece  30  has a recess  32  into which the heads  28  of the various valves project. A part forming a cam  34  which is guided in translation by guide stems  36  and  37  arranged parallel to the axis XX′ can move in longitudinal translation in this recess  32 . The cam  34  is secured to a slider  38  which can move in translation along the upper face  30   a  of the guide piece  30 , the longitudinal movements of the slider being transmitted to the cam  34 . The slider  38  is equipped with a locking push-button  40 . At rest, the push-button  40  secures the slider to the body of the torch  10 . It is necessary to depress the push-button  40  to free the slider  38  and allow it to move. The cam  34  has four ramp-like offset lateral faces allowing action on the control heads  28  of the various valves  16  to  22  in a synchronized pattern which will be explained later. 
     It is to be emphasized that the cutting oxygen supply valve  22  is of the type that can be adjusted progressively. For that, it comprises a shutter member  44  which has the desired profile  45  for obtaining the desired curve of delivery as a function of the displacement of its control stem  47 . 
     The torch is also equipped with two delivery control taps, one for the oxygen and one for the fuel. FIGS. 1 to  3  show the tapped bosses  46  and  48  into which these adjusting taps are fitted, which taps will be described later in conjunction with FIG.  4 . It is sufficient to recall that each tap comprises an operating handwheel and that the range of adjustment corresponds to slightly less than one turn, and so the position of the handwheel directly indicates the adjustment. These taps take a graduated ring which is positioned after the needle has been mounted on the body, and which allows precise and economical indexing even with conventional machining. These taps can be replaced in the event of wear or damage following an impact, for example, with the same simple indexing procedure. 
     These taps are used only to adjust and not to open and close the gas passages and are therefore far lighter in duty than the taps on conventional torches. However, with a view to the reliability and durability of this appliance, their design separates the functional surfaces that are to provide sealing from those which are to throttle the delivery. 
     These taps allow the gas deliveries to be adjusted beforehand, without the flame having been lit. As a preference, the way in which the appliance is used therefore gives an indication of the mean position of each of the taps for each type or size of nozzle that is to be fitted to the torch. With this preliminary adjustment, the flame can be lit correctly; if the user wishes to refine or customize his settings, he may operate the taps again. 
     By virtue of these separate means for controlling the opening and closing of the gas passages, the flame can be extinguished without touching the taps. Thus, the refined or customized settings are not lost. Any user who has frequently to change nozzle or to carry out different types of work requiring different settings may also devise his own chart and apply it, making reference to the indexes on the handwheels. Such taps thus contribute to the ease and consistency of the work, while saving time and gas. 
     Referring now to FIGS. 1,  2  and  5 , the use of the cutting torch according to the invention will be described. When switched off, the slider  38  of the control means occupies an extreme position  1  depicted in FIG.  1 . In this position, the locking push-button  40  is at rest and immobilizes the slider  38 . In position  1 , the cam  34  does not act, via any of its active faces, on any of the control heads of the valves  16  to  22  and these are therefore all closed. The locking using the push-button  40  prevents any accidental operation to the torch. 
     To make use of the torch, the user depresses the locking button  40  and gradually moves the slider and therefore the cam  34 . The latter causes the opening, in turn, of the heating oxygen circuit valve, the heating fuel circuit valve and the pilot fuel circuit valve, also, in this last position, giving rise to the activation of the ignition system which, for example, consists of a piezo-electric system. Thus, the pilot and the main flame are lit in turn. 
     When the slider reaches a position  2  defined by a hard point and which is therefore a stable position, the cam occupies a position such that the valves  18  and  20  remain open while the valve  16  is closed, extinguishing the pilot. Furthermore, in this position, the cam has not yet begun to cause the cutting oxygen supply valve  22  to open. If the slider is moved further, beyond its position  2 , that is to say to the left in the case of FIG. 1, the cam  34  keeps the valves  18  and  20  open and gradually opens the valve  22  corresponding to the cutting oxygen. A cutting jet is thus obtained, the delivery of which is progressive as a result of the proportional opening of the valve  22 . When the slider  38  reaches the second end of its travel corresponding to position  4  in FIG. 5, the cutting oxygen valve  22  is fully open and the locking push-button returns to its rest position, thus immobilizing the cam  34  in the cutting position. 
     If there is a desire to interrupt the cutting operation while the slider is in its position  4 , the locking push-button  40  is depressed and the slider returns to its position  2  under the effect of return means which have not been depicted in the figure. This movement causes the valve  22  to close and therefore shuts down the cutting jet as the slider returns to its position  2 . In this position  2 , which is stable by virtue of the presence of the hard spot, the torch supplies just the main flame. If there is a desire to shut the torch down completely, the slider is pushed to the right, that is to say to position  1 , which causes the heating oxygen and fuel valves  18  and  20  to close. When the slider has been returned to its position  1 , the heating flame is therefore interrupted and the slider is locked again by the locking push-button. 
     Referring now to FIG. 4, one preferred embodiment of the adjusting tap  78  will be described. This tap comprises a body  80  intended to be fixed to the boss  46  or  48  of the torch body. The body  80  defines a chamber  82  of cylindrical overall shape, with a gas inlet pipe  86  and an axial gas outlet  88  opening into its bottom  84 . The pipe  88  is connected to the bottom by a conical portion  90  of predetermined profile. The bottom  84  of the chamber is equipped with an annular rib  92  surrounding the conical portion  90 . 
     Mounted in the cylindrical chamber  82  is a moving needle  94 , the lower end of which defines an axial adjusting portion  96 , of essentially conical shape, and a peripheral sealing zone  98  arranged opposite the rib  92 . The needle is equipped with a seal  100  and with a return spring  101  mounted between the bottom  84  of the chamber  82  and a shoulder  102  on the needle, and which tends to move the needle away from the bottom  84  of the chamber. 
     The needle  94  is controlled by a rotary handwheel  104  comprising a cylindrical operating skirt  106  and a threaded rod  108  which collaborates with a tapping  110  formed at the upper part of the chamber  84 . A ball  112  is inserted between a conical recess  114  made at the end of the rod  108  and the upper end  115  of the needle. This method of connection between the handwheel  104  and the needle  94  makes it possible to prevent the rotational movement of the handwheel from being transmitted to the needle. 
     A seal  116  is inserted between the internal face of the skirt  106  and the cylindrical extension  118  of the body of the tap. The seal  116  is used to brake the handwheel  104  with respect to the body of the tap to prevent undesired handwheel rotation. Finally, a ring with an index  120  is mounted to rotate freely with respect to the body of the tap. Once initial calibration of the tap has been performed, this ring is secured to the tap body. 
     The operation of the tap is detailed hereinafter. 
     When the handwheel is brought into its closed position, the sealing zone  90  of the needle is pressed against the annular rib  92 , and this interrupts the communication between the inlet  86  and the outlet  88 . By contrast, when the needle is in this position, there is no contact between the adjusting part  96  of the needle and the frustoconical portion  90  of the needle seat. 
     By causing the handwheel  104  to turn, a corresponding movement of the adjusting portion  96  of the needle with respect to the frustoconical portion  98  is caused, making it possible to adjust the delivery. 
     FIGS. 6 and 7 illustrate one embodiment of a heating torch comprising a control in accordance with the invention. 
     This torch can be distinguished from the one described in conjunction with FIGS. 1 to  3  only in the function of the valves and in the geometry of the ducts made in the torch body for connecting the oxygen and fuel inlets to the outlet nozzles via the four valves and the two adjusting taps. 
     According to this embodiment, the valve  60  is used to supply the pilot with fuel, the valve  62  is used to supply the main flame with fuel, the valve  64  is used to supply oxygen to the control of the pilot ignition system which, for example, is of the piezo-electric type, and the valve  66  is used to supply the main flame with oxygen. 
     The four valves  60  to  66  produce on/off control. As in the case in the torch of FIGS. 1 to  3 , the oxygen and fuel gas deliveries are adjusted using two adjusting taps mounted in the tapped attachment bosses  68  and  70 . 
     The way in which the heating torch of FIGS. 6 and 7 works is as follows. 
     When switched off, the slider  38  occupies a stable position at the first end of its travel and is locked in place by the push-button  40 . The cam  34  does not act on any of the valve stems and the four valves are closed. To use the heating torch, the slider  38  is pushed to the left (FIG. 6) after the push-button  40  has been depressed. This movement of the slider  38  and therefore of the cam  34  causes the successive opening of the valve  66  of the heating oxygen circuit, the valve of the heating fuel circuit and the valve of the pilot fuel circuit and that of the ignition valve. The main flame is thus obtained. The slider  38  is then moved to the second end of its travel which constitutes a stable position by virtue of a hard spot. 
     A welding torch according to the invention will be described with reference now to FIG.  8 . 
     The slider  138  is mounted so that it can move in translation parallel to the axis XX′ of the body of the torch. It is locked in the rest and work position by a push-button  140  comprising a tooth  143  which presses at the two ends  150 A and  150 B of a ramp  150  secured to the torch body. A return spring  144  keeps the push-button in the up position and therefore keeps the tooth pressed against the ramp when there is no deliberate action on the push-button. 
     Valves respectively supply oxygen to the main flame, fuel to the main flame and fuel to the pilot, only the valve  170  being depicted in the figure. The valves are activated by three cams secured to the slider  138 , only the cam  130  being depicted. 
     In the rest position, the valves are closed. To move to the work position, the push-button  140  has to be depressed, which has the effect of disengaging the tooth  143  from the ramp  150  and thus, for example by resting the thumb on the slider, of allowing the slider  138  and therefore the cams  160  to  162  to translate, these cams, during the translational movement, acting on the valves  170  to  172 . 
     When the slider and the secured parts reach the work position, at the end of the ramp  150 , the tooth  143  comes to rest on. the end  150 B of the ramp and immobilizes the slider. The first two valves are kept activated. The valve corresponding to the pilot fuel is activated only temporarily during the translational movement of the slider  138 . During this temporary activation, a certain amount of fuel is sent to the pilot and, at the same time, the piezo-electric generator  151  is activated and generates a spark which ignites the pilot. The pilot ignites the main flame. To extinguish the main flame and return to the rest position, all that is required is to push the push-button  140 , which has the effect of releasing the tooth  143  from the ramp. The spring  141  causes the slider  138  to return to the rest position. The tooth  143 , under the effect of the spring  144 , comes back to rest on the end  150 A of the ramp as soon as the pressure on the push-button  140  is released. 
     A torch according to the invention may, according to the architectural variant considered, be used for implementing a method for cutting, welding, heating, or the like, one or more pieces of metal, particularly pieces of steel, and be so using oxygen or a gas containing oxygen as oxidizing gas, and on the other hand, using acetylene or any other fuel gas, particularly hydrocarbons, such as propane or natural gas for example.