Abstract:
A blast gate to control the application of vacuum pressure to a particulate generating machine so that particulate may be drawn away from the machine and isolated in a vacuum container. The blast gate may be opened when either a vacuum or particulate generating machine is switched on. The blast gate is designed to be inserted in a duct leading from the vacuum to the particulate generating machine. The electromechanical design allows two switches to be activated by a mechanical rotating arm. The switches respectively allow the gate to be held in the open position or in the closed position as well as activating the mechanical arm whereby the gate is moved to the open or closed position.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/397,261, filed 9 Jun. 2010. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention is used in vacuum collection systems as seen in machine shops where waste particulate is generated from the cutting, turning or shaping of wood, plastic, metal and like materials. Specifically, this invention relates to an electro-mechanical blast gate, that when open, allows the vacuum to reach and remove particulate from a particulate generating machine or alternatively, when closed, isolates that machine from the vacuum system. 
         [0004]    2. Description of the Related Art. 
         [0005]    The inhalation of particulate matter associated with the cutting, turning and shaping of wood, plastic and metal have known adverse health effects. Further, the accumulation of particulate in the workspace creates a fire hazard and, in some cases, a slip and fall hazard and adds to the general disorganization of the work area. 
         [0006]    Blast gates are known in the art, however, they tend to be complex and expensive. Their driving mechanism can be electrical, hydraulic or pressurized air. Most of these systems rely on a centralized controller. Because they are part of a larger extensive system, control lines must be extended to each gate thereby increasing the expense, complexity and the chance of failure. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention presents a simple, electro-mechanical solution for the collection and isolation of particulate matter in the work space. Rather than being part of a complex centralized system, the present invention can be attached to an individual machine and opened only when the particulate generating machine or associated vacuum machine is activated. This is especially effective when the shop is set up with vacuums individually attached to a machine or a single vacuum attached to a discrete machine grouping. 
         [0008]    The use of a single arm, rotating in a single direction which opens and closes the gate results in efficient operation that can greatly reduce gate failure due to its simplicity. Fully enclosing the gate in a sleeve prevents the accumulation of dust resulting in the binding of the gate, thus allowing reliable operation. 
       OBJECTS OF THE INVENTION 
       [0009]    It is an object of the invention to allow vacuum pressure to a particulate generating machine, thus allowing the removal of hazardous dust 
         [0010]    It is an object of the invention to reduce the consumption of energy by opening only when a particulate generating machine or vacuum machine is activated. 
         [0011]    It is a further object of the invention to reduce the number of parts and the movement thereof to increase the reliability of the gate. 
         [0012]    It is a further object of the invention to enclose the gate in a sleeve whereby particulate is prevented from binding or blocking gate operation. 
         [0013]    These and other objects and advantages are revealed in the accompanying specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a partial cross section perspective side view of the blast gate. 
           [0015]      FIG. 3  is a perspective view of the underside of the blast gate. 
           [0016]      FIG. 5  is a perspective view of the upper side of the blast gate. 
           [0017]      FIG. 7  is a partial cross section perspective view of the upper side of the blast gate. 
           [0018]      FIG. 9  is a partial cross section perspective of the underside of the blast gate. 
           [0019]      FIG. 11  is a side and top plan view of the driving arm in rotating configuration. 
           [0020]      FIG. 13  is a side and top plan view of the driving arm in stalled configuration. 
           [0021]      FIG. 15  is an electrical schematic showing switch configuration of the blast gate closing. 
           [0022]      FIG. 17  is an electrical schematic showing switch configuration of the blast gate in a closed position. 
           [0023]      FIG. 19  is an electrical schematic showing switch configuration of the blast gate opening. 
           [0024]      FIG. 21  is an electrical schematic showing switch configuration of the blast gate in an open position. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0025]      FIG. 1  illustrates a partial cross-sectional view of the Blast Gate. The gate  2  is disposed within gate housing  4 . Gate housing  4  is composed of a gate housing upper surface  6 , a gate housing lower surface  8 , first gate housing side  10 , second gate housing side  12 , and third gate housing side  14  which are joined in such a way to form a pocket into which gate  2  is inserted, specifically, through gate housing open side  16 . Gate  2  is composed of a first planar gate segment  18  which slides within gate housing side  4 . Second planar gate segment  20  is attached to first planar gate segment  18  and is perpendicular thereto. Upper gate housing surface  6  exhibits first gate housing aperture  22 . First duct connector  24  is attached to upper gate housing surface  6  in such a manner as to be fully disposed over upper gate housing surface aperture  22 . A duct emanating from a vacuum is attached to first duct connector  24 . 
         [0026]    Turning now to  FIG. 3 , lower gate housing surface  8  is shown. A cylindrical second duct connector  28  is disposed over second gate housing aperture  26 . A duct extending to the particulate generating machine is connected to the second duct connector.  FIG. 3  also shows controller housing  30 . Controller housing  30  is composed of upper controller housing  32  and lower controller housing  34 . The controller housing  30  is attached to the gate housing  4  by means of a first perforated bracket  36  and second perforated bracket  38  which are fixed to gate housing lower surface  8 . Lower controller housing  34  exhibits first connector wing  40  and second connector wing  42 , which are respectively connected to first bracket  36  and second bracket  38 . 
         [0027]      FIG. 5  further illustrates the relative placement of upper controller housing  32  and lower controller housing  34 . Upper controller housing  32  is secured to lower controller housing  34  by means of any standard fastener through corresponding perforations. First controller housing connector wing  42  is shown with perforations  44  which correspond to perforations in the first bracket  38 . A similar configuration is seen between first connector wing  40  and second bracket  36 . 
         [0028]      FIG. 7  shows upper controller housing  32  covering motor  46 . Motor  46  is an AC synchronous motor similar to commercially available Polyvolt PN SG-J6L8-24-6. Motor  46  is fixed to lower controller housing top surface  48 . 
         [0029]    Moving now to  FIG. 9 , it can be seen that lower controller housing top surface underside  112  is perforated such that motor shaft  50  extends through lower controller housing top surface  48  by way of top surface aperture  52 . 
         [0030]    Driving arm  54  is L-shaped and exhibits driving arm first end  56 , driving arm second end  58 , and driving arm spacer segment  60 . Driving arm spacer segment  60  holds driving arm  54  away from lower controller housing top surface underside  112  such that driving arm  54  may pass over first switch  62  as driving arm  54  traces its circular path within lower controller housing  34 . Driving arm spacer segment  60  is formed as part of driving arm  54  and is attached to driving arm second end  58 . Driving arm second end  58  and driving arm spacer segment  60  are perforated, allowing motor aperture  50  to be disposed within driving arm second end aperture  64 . Driving arm first end  56  also exhibits driving arm first end aperture  66 , through which switch activating pin  68  is disposed. As driving arm  54  traces its rotational path within lower controller housing  34  and passes over first switch  62 , the switch activating pin  68  makes contact with first switch rocker  70 . Switch activating pin  68  is rotatably disposed within driving arm first end aperture  66  but is fixedly attached to slotted bracket  72 , allowing slotted bracket  72  to rotate relative to driving arm  54 . Slotted bracket  72  exhibits slot  74  through which second planar gate segment  20  is disposed. It can be seen that, as driving arm  54  traces its rotational path within lower controller housing  34 , slotted bracket  72  will withdraw gate  2  from within gate housing  4 , thereby no longer occluding first gate housing aperture  22 , and second gate housing aperture  26 . It can also be seen that as driving arm  54  continues through its rotational path, slotted bracket  74  will slide along the length of second planar gate segment  20 . 
         [0031]      FIG. 9  illustrates driving arm  54  at a point in its rotational path whereby gate  2  is inserted within gate housing  4 . In  FIG. 9 , driving arm  54  is exhibiting a clockwise rotation. As driving arm  54  continues it clockwise rotation, driving arm  54  rotates away from gate housing  4  and, consequently, as slotted bracket  72  slides along gate  2 , it will withdraw gate  2  from gate housing  4 . 
         [0032]    Turning again to  FIG. 7 , first switch  62  is illustrated attached to lower controller housing top surface underside  112 , directly opposite to second switch  76 . It can be seen that when driving arm  54  continues on its clockwise rotational path, switch activating pin  68  will come into contact sequentially with second switch rocker arm  78  as well as first switch rocker arm  70 . 
         [0033]      FIG. 11  illustrates driving arm  54  with the internal slip clutch mechanism  80 . Internal slip clutch mechanism  80  is composed of compression spring  82 , compression spring set screw  84 , and ball  86 . Internal slip clutch mechanism  80  is disposed within slip clutch aperture  114  which extends from driving arm second end  58  through driving arm second end aperture  64 . Ball  86  rests against compression spring first end  88 . Compression spring second end  90  rests against compression spring set screw  84 . Compression spring  82  is compressed against compression spring set screw  84  and ball  86 , forcing ball  86  against motor shaft indent  92 . When the torque exerted by motor  46  is of insufficient force to overcome the compression of compression spring  82  exerts against ball  86  which, in turn, is exerted against the motor shaft indent  92 , driving arm  54  will rotate in conjunction with the rotation of motor shaft  50 . This is the configuration seen in  FIG. 11 . 
         [0034]    Turning now to  FIG. 13 , should the driving arm  54  bind or encounter an obstacle, causing it to stop its rotational path, the force of the rotation of motor shaft  50  would then overcome the compression force of compression spring  82 . Should this occur, ball  86  would be forced up the slip clutch aperture  114 . This would allow the motor shaft  50  to continue to rotate within driving arm second end aperture  64  with driving arm  54  remaining stationary. Slip clutch Aperture  114  exhibits slip clutch aperture first end  96  which is a smooth bore and slip clutch aperture second end  95  which is threaded whereby compression spring set screw  84  may be threadedly disposed. 
         [0035]    Now turning to  FIG. 15 , we see a schematic showing an electrical power source  100  connected to first common electrical line  102  which is, in turn, connected to first motor pole  104 . The second common electrical line  106  is connected to blast gate control switch  108 . When the blast gate control switch is in the position illustrated in  FIG. 15 , and when first switch  62  is closed, the motor  46  is electrified through motor pole switch  110 . 
         [0036]    In this configuration, the motor  46  has been energized and starts to rotate the driving arm  54 . Driving arm  54  then rotates in a clockwise fashion until such time as switch activating pin  68  comes into contact with first switch  62  breaking first switch circuit  116  and causing the driving arm  54  to stop rotating. Blast gate control switch  108  is activated in conjunction with the on/off switch of the individual particulate generating machine, whether it be a table saw, band saw, lathe, or other machine. Thus, when the particulate generating machine is switched off, or alternatively, when a vacuum machine is switched off, the blast gate control switch  108  closes first switch circuit  116 , thus allowing the motor to rotate. 
         [0037]    Turning now to  FIG. 17 , here switch activating pin  68  now depresses the first rocker arm switch  70  which opens the circuit and stops the rotational force of the motor  46 . In this position, the driving arm  54  has moved slotted bracket  72  toward gate enclosure  4  and, consequently, gate  2  has been inserted into gate enclosure  4  to its maximum extent, thereby closing the gate housing apertures  22  and  26 . 
         [0038]    Turning now to  FIG. 19 , we see that the particulate generating machine has now been turned on, or alternatively the vacuum machine has been turned on, thereby breaking first switch circuit  116  and causing blast gate control switch  108  to close second switch circuit  118 . With second switch circuit  118  closed, electrical current is provided to motor pole  110 , resulting in the operation of the motor  46  rotating the driving arm  54  again in a clockwise direction. The driving arm  54  will continue to swing through its rotational path until switch activating pin  68  makes contact with second switch rocker  78 , thereby opening second switch  76 . 
         [0039]      FIG. 21  illustrates a situation in which switch activating pin  68  of the driving arm  54  has now made contact with second switch rocker  78 , thereby opening it and breaking the circuit which had energized the motor. Thus, the gate will then stop in the given position in which the driving arm  54  with the attached slotted bracket  72  will have pulled gate  2  out of gate housing  8 , thereby opening the aperture.