Patent application title: Blast gate
Dennis Coleman (Champaign, IL, US)
Dennis Coleman (Champaign, IL, US)
Gavin Steele (Champaign, IL, US)
IPC8 Class: AA47L900FI
Class name: Machines with air blast or suction combined, e.g., with signal or indicator
Publication date: 2012-03-22
Patent application number: 20120066860
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.
1. A blast gate and controller for the application of vacuum pressure to
particulate generating machines comprising: a. a controller housing
connectable to a gate housing, b. a controller mechanism contained within
said controller housing, c. a gate slidably disposed within said gate
housing, d. said controller mechanism connectable to said gate whereby
said gate may be withdrawn and inserted within said gate housing. e. said
gate housing having a first aperture and a corresponding second aperture,
said first and second apertures capable of being opened and closed by
said gate, f. said first aperture connectable to a duct leading to a
vacuum and said second aperture connectable to a duct leading to a
particulate generating machine.
CROSS REFERENCE TO RELATED APPLICATIONS
 This application claims the benefit of U.S. Provisional Application No. 61/397,261, filed 9 Jun. 2010.
BACKGROUND OF THE INVENTION
 1. Field of the Invention
 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.
 2. Description of the Related Art.
 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.
 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
 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.
 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
 It is an object of the invention to allow vacuum pressure to a particulate generating machine, thus allowing the removal of hazardous dust
 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.
 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.
 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.
 These and other objects and advantages are revealed in the accompanying specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a partial cross section perspective side view of the blast gate.
 FIG. 3 is a perspective view of the underside of the blast gate.
 FIG. 5 is a perspective view of the upper side of the blast gate.
 FIG. 7 is a partial cross section perspective view of the upper side of the blast gate.
 FIG. 9 is a partial cross section perspective of the underside of the blast gate.
 FIG. 11 is a side and top plan view of the driving arm in rotating configuration.
 FIG. 13 is a side and top plan view of the driving arm in stalled configuration.
 FIG. 15 is an electrical schematic showing switch configuration of the blast gate closing.
 FIG. 17 is an electrical schematic showing switch configuration of the blast gate in a closed position.
 FIG. 19 is an electrical schematic showing switch configuration of the blast gate opening.
 FIG. 21 is an electrical schematic showing switch configuration of the blast gate in an open position.
DESCRIPTION OF EMBODIMENTS
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
Patent applications by Dennis Coleman, Champaign, IL US
Patent applications in class Combined, e.g., with signal or indicator
Patent applications in all subclasses Combined, e.g., with signal or indicator