Patent Publication Number: US-2005133489-A1

Title: Screw air compressor for a welder

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      The present application is a continuation and claims priority of allowed U.S. Ser. No. 10/605,738 which is a continuation of U.S. Pat. No. 6,674,046. 
    
    
     BACKGROUND OF THE INVENTION  
      The present invention relates generally to combined welder and compressor units, and more particularly to a unit of this type having a belt-driven screw air compressor configured to provide compressed air for pneumatic operations.  
      Portable welding and compressor units transportable to a work site are known. Typical known units include a lightweight frame consisting of metal tubing on which is mounted an internal combustion engine that is directly connected to a generator which generates an amperage to operate the unit or welder. The generator further provides auxiliary alternating current for operating auxiliary equipment, such as an air compressor. The air compressor provides compressed air for pneumatic equipment as well as certain welding applications, such as operating a plasma cutting torch. Other known portable welding and compressor units include an engine, alternator, compressor, and air tank assembly mounted within a housing along an extended length of the housing.  
      While combined welder and compressor units operate satisfactorily, they have several disadvantages. First, such systems tend to be bulky and/or heavy. In a typical unit, a welder may weigh approximately 2000 pounds and have a separate compressor unit adding approximately 1500 pounds. Transporting such systems to various work sites is difficult and time consuming. Second, known welder and compressor units incorporate air compressors that have high rates of mechanical breakdowns. Moreover, air compressors are often positioned within the welding unit, and in instances of air compressor breakdown, associated repair costs and welding unit downtime may be substantial.  
      There is a need for a welder and compressor unit or combination that has improved portability and durability. It would therefore be desirable to have a more lightweight and efficient air compressor than current air compressors, that can be externally mounted to an internal combustion engine for rapid repair and replacement.  
     BRIEF DESCRIPTION OF THE INVENTION  
      The present invention is directed to an improved welder and compressor combination to supply compressed air and electrical current for pneumatic and arc welding operations to overcome the aforementioned concerns.  
      The invention includes a portable welder having an internal screw air compressor. Screw air compressors are generally more durable than reciprocating air compressors used with known devices and have additional desired characteristics that include low initial cost, compact size, and low weight. Further, a screw air compressor, especially one belt driven by an engine as in the present invention, is easy to repair and maintain which is desirable in portable equipment. In addition to a screw air compressor, the present invention also includes an engine mounted within a housing of the welder which provides power to an electric current generator for generating the electrical current used during welding operations. The engine has a pulley arrangement connected by belts that drive the screw air compressor, an alternator, and an engine cooling fan. Further included is a clutch assembly connected to the screw air compressor that controls the screw air compressor which provides compressed air for pneumatic operations.  
      In accordance with one aspect of the present invention, a welder and compressor combination includes a transportable housing having an engine mounted therein. An electrical generator is also mounted within the housing and driven by the engine, and provides an arc welding current for use in welding operations. The welding and compressor combination further includes a screw air compressor that provides compressed air as needed. The screw air compressor is preferably mounted to the engine to permit rapid installation during manufacture and removal for replacement or repair of the screw air compressor as may be needed. The screw air compressor also includes a clutch assembly driven by a belt in operable association with the engine. The clutch assembly engages or disengages the screw air compressor from the engine.  
      In accordance with another aspect of the present invention, an engine-driven welder combination is disclosed and includes a welder housing having internal components mounted thereto. An engine is also mounted within the welder housing, and has an electrical generator and screw air compressor connected thereto. The engine rotates the electrical generator to produce an arc welding current for welding operations. The screw air compressor provides compressed air for air-driven tools. The screw air compressor has a disengageable drive pulley connected to the engine and is mounted on the engine. The screw air compressor is externally mounted to the engine in such a fashion to allow easy installation and provide quick removal for servicing.  
      In accordance with yet another aspect of the present invention, a welding and air compression system includes a means for compressing air having at least one screw-type means rotatable in a longitudinal cylinder to generate compressed air, and a means for generating an arc welding current. A means for driving the air compressing means is provided along with a means for generating an arc welding current. Examples of such means include an internal combustion engine configured to drive an electric generator and a screw air compressor. The welding and air compression system further includes a means for connecting air to the means for driving, and a means for regulating the means for compressing air.  
      Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The drawings illustrate one preferred embodiment presently contemplated for carrying out the invention.  
      In the drawings:  
       FIG. 1  is a perspective view of a welder and compressor combination incorporating the present invention.  
       FIG. 2  is a perspective view of a portion of the welder and compressor combination with a housing cover removed.  
       FIG. 2A  is a side view of the welder and compressor combination of  FIG. 2 .  
       FIG. 3  is a perspective view of a portion of an engine showing a pulley arrangement of the welding and compressor combination of  FIG. 2 .  
       FIG. 4  is an exploded view of  FIG. 3  without the belts for driving the pulley arrangement.  
       FIG. 5  is a front perspective view of a pair of mounting brackets shown in  FIG. 4 .  
       FIG. 6  is a rear perspective view of the pair of mounting brackets of  FIG. 5 .  
       FIG. 7  is a schematic of the screw air compressor air and oil routing system incorporated in the combination of  FIG. 1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring now to  FIG. 1 , a portable engine-driven welding and compressor combination or system  10  is provided. The welder combination  10  has an outer housing  12  that has one or more air vents  14  for cooling internal components of the welder combination  10 . The housing  12  can be easily removed to permit access to the internal components for maintenance and service. A plurality of support members  16  provide stabilization for the welder combination  10  when placed on a generally level surface, such as surface  18 . An upper surface  20  of the welder combination  10  includes a lifting hook  22  extending therethrough for lifting and transporting of the welder combination  10 . Also attached to the upper surface  20  is an exhaust system  24  that lowers noise and removes exhaust gas from the welder combination  10 .  
      The welder combination  10  includes a control panel  26  that has various control elements and gauges for operating the welder combination  10 . A plurality of gauges  28  measure various parameters of the welder combination  10 . Measured parameters can include oil pressure, fuel level, oil temperature, battery amperage, air pressure, and engine running time of the welder combination  10 . Control panel  26  also has a control dial  30  and an ampere range switch  32  which are used to select a voltage/amperage for welding operations. Process selector switch  34  selects the type of weld output. The weld output is determined by the type of welding process. Examples of weld processes that may be implemented include stick welding, TIG welding, air-carbon arc cutting, and various wire feed processes. Electrical outlets  36  provide power for electrically driven devices, such as saws, drills, etc. Control panel  26  also includes a compressor on/off switch  31  and an engine control switch  33  to independently control the compressor and engine, respectively.  
      The control panel  26  also includes multiple power connections such as single phase power connect  38 , optional three-phase power connect  40 , and weld-power receptacles  42 . An optional polarity switch  44  can be used to select the polarity of the weld output. Typical selections include direct current electrode negative, direct current electrode positive, and alternating current. A panel remote switch  46  and remote receptacle  48  select remote control of the welder combination  10  in instances where welding operations are remotely located from the welder combination  10 . Positive  50  and negative  52  battery charge connections are used for battery jumpstart or charging, and are positioned adjacent to a system output or shut-off valve  54 . Upon engaging of the compressor clutch and opening of valve  54 , compressed air is supplied for air assisted carbon arc cutting or to air driven power tools and other pneumatic operations.  
      Referring now to  FIG. 2 , a perspective view of a portion  56  of the welder combination  10  of  FIG. 1  is shown with the housing cover  12  removed. An internal combustion engine  58  is mounted to a frame assembly  64  between a radiator shroud  60  and a lifting hook support member  62 . The engine  58 , in a preferred embodiment, is oil cooled and configured to recirculate engine cooling oil. The lifting hook support member  62  secures to the frame assembly  64  for structural support during lifting of the welder combination  10 . The frame assembly  64  has air vents  14  that permit air flow through the welder combination  10  to cool the internal components. Cross-brace  66  provides structural support for the frame assembly  64 . An electrical generator  67  configured to generate an arc welding current is mounted within the housing  12  of the welder combination  10  and driven by the engine  58 . The welder combination further includes a screw air compressor  68  mounted to the engine  58  that is configured to provide compressed air to the shut-off valve  54  of  FIG. 1 . The screw air compressor  68  is fluidly connected to an oil separator  70 , a coalescing filter  72 , which combine to separate oil from an air/oil mixture and a first particle oil filter.  
      The internal combustion engine  58  of the welder combination  10  includes an air intake connected to an intake manifold and engine head  78 . The engine head  78  is mounted to an engine block  80 , which collectively form the engine  58 . A pulley arrangement  82  is bolted to both the engine head  78  and the engine block  80  and includes a fan blade hub  84  rotated by a first drive belt  86 , such as a serpentine belt. The first drive belt  86  further connects to an alternator pulley  88  that drives an alternator  90  by a first crankshaft pulley  92 . A belt tensioner  94  connects to a mounting bracket  102  to maintain tension on a second drive belt  96  that drives the screw air compressor  68  driven by a second crankshaft pulley  108 .  
      Referring now to  FIG. 2A , a side view of the portion  56  of  FIG. 2  is shown. Frame assembly  64  connects to support member  62  which is attached to lifting hook  22 . The internal combustion engine  58  is shown having fan blade hub  84  attached to the engine head  78  as previously discussed with reference to  FIG. 2 . A fan (not shown) is attached to fan blade hub  84  that is housed in the radiator shroud  60 . Engine block  80  has alternator  90  mounted thereto which is driven by the first drive belt  86 . The electrical generator  67  mounts to the engine block  80  and is rotated by the engine  58  to generate the arc welding current used in welding operations. Oil separator  70  is mounted to the frame assembly  64  with a mounting plate  98 . An oil return line  100  of the oil separator  70  connects the oil separator  70  to the radiator, as will be described with reference to  FIG. 7 . An air intake  76  is provided to supply air to the screw air compressor  68 .  
       FIG. 3  is a perspective view of the pulley arrangement  82  connected to the engine head  78  and the engine block  80 . The screw air compressor  68  bolts to a first mounting bracket  102  that is connected to the engine head  78  via bolts  104 . The screw air compressor pulley  106  of the pulley arrangement  82  is driven by the second drive belt  96  which in turn is driven by the second crankshaft pulley  108 . The screw air compressor  68  is controlled by a clutch assembly  107  which is connected to air compressor pulley  106 . Preferably, the clutch assembly  107  is a magnetic clutch assembly. Tension on the second drive belt  96  is maintained by a roller  110  of the belt tensioner  94 .  
      A second mounting bracket  112  is mounted to the engine block  80  via a set of bolts  114 , and is connected to the first mounting bracket  102  via bolts  116  to attach the pulley arrangement  82  to the engine  58 . The fan blade hub  84  is secured to the second mounting bracket  112 , and is driven by the first drive belt  86 . The first drive belt  86  also drives alternator pulley  88  and is driven by first crankshaft pulley  92  of the pulley arrangement  82 . Also included is an adjustable slide linkage  118  that has bolt  120  which connects to the second mounting bracket  112  to position the alternator  90  and provide tension to first drive belt  86 . That is, the alternator  90  can be repositioned according to the position of bolt  120  along the adjustable slide linkage  118  to provide more or less tension on the first drive belt  86 .  
      Referring now to  FIG. 4 , an exploded view of  FIG. 3  showing the connections of the components to one another without the first and second drive belts  86 ,  96  is shown. The pulley arrangement  82  includes a mounting plate  122  for connecting the screw air compressor  68  to the first mounting bracket  102  via bolts  124 . Bolt holes  126  are used to attach the screw air compressor  68  to the first mounting bracket  102 . Belt tensioner  94  is connected to the first mounting bracket  102  at bolt hole  128  with an appropriate fastener. The fan blade hub  84  is rotatably secured to the second mounting bracket  112  with a bolt through bolt hole  130 . Bolt hole  132  permits connection of the adjustable slide linkage  118  to the second mounting bracket  112 . Bolt  134  connects the slide linkage to the alternator  90 . The alternator  90  is also connected to the second mounting bracket  112  by bolt  136  which passes through a pair of bolt holes  138 . The first and second mounting brackets  102 , 112  are preferably attached to the engine  58  in such a manner as to not interfere with the connection between the cylinder head  78  and engine block  80 . That is, by mounting first bracket  102  to the cylinder head  78  and mounting the second bracket to the block  80 , and then bolting the first mounting bracket  102  to the second mounting bracket  112 , the seal between the cylinder head  78  and block  80  is not compromised.  
       FIGS. 5 and 6  show respective front and rear views of the first  102  and second  112  mounting brackets. The first mounting bracket  102  is configured to connect the screw air compressor to the engine such that a longitudinal length of the screw air compressor is aligned with a longitudinal length of the engine. The second mounting bracket  112  includes bolt holes  140  configured to permit connecting of the first mounting bracket  102  to the second mounting bracket  112 . The second mounting bracket  112  also has contact surfaces  142  configured to fit smoothly against lower surfaces  144  of the first mounting bracket  102 . Surface  146  is used to mount and align belt tensioner  94 . The first and second mounting brackets  102 ,  112  also include bracket stiffeners  148  that add structural strength. Preferably, a backside  149  of the first mounting bracket  102  is contoured to the shape of the cylinder head  78  and a backside  150  of the second mounting bracket  112  is contoured to the shape of the engine block  80  to provide maximum support for the screw air compressor  68 .  
      Referring now to  FIG. 7 , a schematic of the compressor air and oil routing system  152  is provided. The compressor system  152  includes an air filter  154  that directs ambient air to an inlet control valve  156 . Air pressure along line  158  controls the inlet control valve  156 , which regulates air flow into the screw air compressor  68  of  FIG. 2 . The screw air compressor  68  provides a compressed air/oil mixture along line  162  to the oil separator  70 . A high temperature switch  164  monitors the temperature of the air/oil mixture and is configured to open a contact (not shown) to disable the magnetic clutch assembly  107  of  FIG. 3  if the temperature exceeds a predetermined limit. After passing through the oil separator  70 , oil exits the oil separator  70  and enter a cooling system that includes a thermostat  168  and a radiator  170 . A manually controlled drain valve  166  is supplied to drain oil from the oil separator  70 . The radiator  170  acts as a dual purpose radiator having two cooling chambers. One of the two chambers cools compressor oil and the other chamber cools engine coolant by circulating engine oil therethrough. Collectively, the oil separator  70 , first particle filter  74 , thermostat  168 , and radiator  170  form a compressor oil cooler assembly capable of reducing the temperature of the filtered oil that returns to the screw air compressor  68  along line  163 .  
      The thermostat  168  includes a control valve that directs oil to either the radiator  170  or the first particle filter  74 . When oil is selected by the control valve to pass through the radiator  170 , it also passes through the first particle filter  74  after flowing though the radiator  170 . After passing through the first particle filter  74 , the oil enters the screw air compressor  68 . The air, including a small amount of remaining oil mist, exiting from the oil separator  70  flows through a system that includes a distribution manifold  174  and a safety valve  176  for limiting pressure in line  178 . Air pressure gauge  180  is provided to monitor line  178 . A low pressure switch  182  is also connected to line  178  to prevent restart of the compressor  68  until pressure in the manifold  174  has reached a minimum value.  
      After entering the manifold  174 , the air/oil mixture from line  178  flows through a coalescing filter  72 . Oil is routed along line  186  through a one-way valve  188  and a second particle filter  190 . After passing through the second particle filter  190 , the oil passes through an orifice  192  which regulates flow to the screw air compressor  68 . Air exiting from the coalescing filter  72  is delivered to a minimum pressure valve  196  by line  194 . If the pressure along line  194  is sufficient, air will pass through the minimum pressure valve  196  to the shut-off valve  54  of  FIG. 1 , which provides compressed air for pneumatic operations of the welder combination  10 . Using air received from the coalescing filter  72 , a pressure regulator  198  regulates air pressure along control pressure line  158  in conjunction with a bleed orifice  200 . Pressure in line  158  controls the position of inlet control valve  156 . Air can also pass from the coalescing filter  72  into a blow-down valve  202  and exit the compressor system  152  through bleed down orifice  204 . Depending on the pilot pressure at  206 , air flow either increases or decreases through the bleed orifice  204  depending on the position of the inlet control valve  156 .  
      In accordance with one aspect of the present invention, a welder and compressor combination includes a transportable housing and an engine mounted within the transportable housing. The welder and compressor combination also includes an electrical generator configured to generate an arc-welding current. The electrical generator is mounted within the transportable housing and driven by the engine. The welder and compressor combination further includes a screw air-compressor having a clutch assembly driven by a belt in operable association with the engine.  
      In accordance with another aspect of the present invention, an engine-driven welder combination includes a welder housing having internal components mounted thereto, such as an engine. The portable engine-driven welder combination further includes an electrical generator connected to and rotated by the engine to generate an arc-welding current. In addition to the electrical generator, a screw air compressor is mounted to the engine. The screw air compressor has a disengageable drive pulley connected to the engine and is mounted on the engine.  
      In yet another aspect of the present invention, a welding and air compression system includes a means for compressing air to generate compressed air and a means for generating an arc-welding current. The means for compressing air has at least one screw-type means in a longitudinal cylinder. The welding and air compression system also includes a means for driving the means for compressing air and the means for generating an arc-welding current, and a means for connecting the means for compressing air to the means for driving. The welding and air compression system further includes a means for regulating the means for compressing air.  
      In another alternative embodiment, the screw air compressor could equivalently be driven from the generator end of the portable engine driven welding and generator combination. That is, the drive shaft from the engine can extend through the generator to allow a belt pulley to be attached thereto and drive a screw air compressor mounted to the generator.  
      The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.