Patent Abstract:
A security gate operating system and method are disclosed, which may comprise a security gate capable of motion between a closed position and an open position; a drive mechanism attached to the security gate and adapted to provide a driving force to the security gate to move the security gate between the closed position and the open position; an electrical drive motor having a drive shaft connected directly to the drive mechanism without a reduction gear between the drive motor and the drive mechanism. The method and system may also comprise the drive motor being a reluctance motor including a switched reluctance motor, and including also a three phase switched reluctance motor. The method and system may also comprise a drive chain operatively connected to the security gate; and a drive sprocket attached directly to the shaft of the drive motor, with the drive sprocket in operative connection to the drive chain. The method and system may also comprise at least one drive arm directly connected to the drive motor shaft and operatively connected to the security gate.

Full Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to the field of security gate operating systems, and more specifically a method and apparatus for simplifying the driving mechanism for a security gate operating mechanism.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is well known to operate security gates with a motor driven mechanism, and FIG. 1 shows one form of such a security gate system and FIG. 2 shows another form of such a security gate. FIG. 3 shows in more detail the front installation of a drive chain mechanism associated with the form of security gate operating mechanism shown in FIG. 1. FIG. 4 shows another form of security gate chain drive operating mechanism, a so-called rear installation, which is associated with FIG. 2. Typical security gates have a number of advantages, however, when AC or DC motors are utilized to drive them, these gates retain some problems that need to be overcome. For example, it is often the case that environmental conditions may cause the gate to be heavier at times than normally expected, e.g., if snow or ice in on the gate, or debris from a storm is on the gate, or a person is playing on the gate, as for example, hanging on to the gate for a ride. When moving the gate under such conditions a higher initial torque than usual is needed and may cause problems in operation, such as motor overload for typical AC or DC motors. In addition, this required initial torque can limit the size of gate that can be operated with a given size and power capability for a given motor, because of the initial torque requirements. Further, when the gate operating mechanism does malfunction, which can occur from time to time for any number of different reasons, until the gate operating mechanism is put back into service, there will most likely be a need to position the security gate into a desired position to block ingress and egress or to unblock ingress or egress, as may be appropriate. Without the operation of the drive motor, e.g., the prior art security gates can be very difficult to reposition, due, e.g., to the presence of a reduction gear or gearbox that is typically necessary to reduce the high rpm motor speed to a speed of the driving mechanism that is necessary for a safe and controlled operation of the security gate movement. The presence of the reduction gear or gearbox presents a load opposing manual movement of the security gate, which in some cases may not be able to be overcome, or at least may require extensive manual force to be applied to the security gate for movement without the operation of the drive motor. The security gate operating mechanism of the prior art are, therefore, subject to improvement, which is the subject matter of the present invention.  
         SUMMARY OF THE INVENTION  
         [0003]    A security gate operating system and method are disclosed, which may comprise a security gate capable of motion between a closed position and an open position; a drive mechanism attached to the security gate and adapted to provide a driving force to the security gate to move the security gate between the closed position and the open position; an electrical drive motor having a drive shaft connected directly to the drive mechanism without a reduction gear between the drive motor and the drive mechanism. The method and system may also comprise the drive motor being a reluctance motor including a switched reluctance motor, and including also a three phase switched reluctance motor. The method and system may also comprise a drive chain operatively connected to the security gate; and a drive sprocket attached directly to the shaft of the drive motor, with the drive sprocket in operative connection to the drive chain. The method and system may also comprise at least one drive arm directly connected to the drive motor shaft and operatively connected to the security gate. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]    [0004]FIG. 1 (Prior Art) shows a security gate operating system of a type in which the present invention may be utilized;  
         [0005]    [0005]FIG. 2 (Prior Art) shows another form of a security gate system of a type in which the present invention may be utilized;  
         [0006]    [0006]FIG. 3 (Prior Art) shows a security gate drive mechanism of the type useful in the security gate operating mechanism of FIG. 1;  
         [0007]    [0007]FIG. 4 (Prior Art) shows another view of the a security gate drive mechanism of the type useful in the security gate operating mechanism of FIG. 1, with the security gate in a position opposite from that shown in FIG. 3;  
         [0008]    [0008]FIG. 5 (Prior Art) shows a security gate drive mechanism of the type useful in the security gate operating mechanism of FIG. 2;  
         [0009]    [0009]FIG. 6 (Prior Art) shows an exploded view of the security gate drive mechanism shown in FIGS. 1, 3 and  4 ;  
         [0010]    [0010]FIG. 7 (Prior Art) shows an enlarged view of a portion of the security gate drive mechanism shown in FIGS. 1, 3 and  4 ;  
         [0011]    [0011]FIG. 8 shows a perspective view of a security gate operating system according to the present invention; and,  
         [0012]    [0012]FIG. 9 shows another perspective view of a security gate operating system according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    Turning now to FIG. 1 (Prior Art), there is shown a known form of security gate system  10 . The security gate system  10  shown in FIG. 1 is an example of a so-called front installation security gate system  10 . The security gate system  10  has a sliding gate  12 , which is partially mounted for sliding movement by mounting brackets  14  and  16  to wall sections  18  and  20 , respectively. The sliding gate  12  has a pair of rollers  22  that engage a track  24 . The gate is driven by a security gate drive mechanism  26 , as more fully described in regard to FIG. 3 below. The security gate  12  is driven by a chain drive, more fully described in regard to FIG. 3 between a pair of physical travel stops  28 .  
         [0014]    Turning now to FIG. 2 (Prior Art) there is shown another form of security gate system  10 ′. The security gate system  10 ′ shown in FIG. 2 is an example of a so-called rear installation security gate system  10 ′. The security gate system  10 ′ also has a sliding gate  12 , which is partially mounted for sliding movement by mounting brackets  14  and  16  to wall sections  18  and  20 , respectively. The sliding gate  12  has a pair of rollers  22  that engage a track  24 . The gate is driven by a security gate drive mechanism  26 , as more fully described in regard to FIG. 3 below. The security gate  12  is driven by a chain drive, more fully described in regard to FIG. 3 between a pair of physical travel stops  28 .  
         [0015]    The difference between the security gate system  10  of FIG. 1 and the security gate system  10 ′ of FIG. 2 is that the chain drive for operating the security gate  12  through movement of chain  30  runs along the bottom of the gate  12  in the embodiment of FIG. 1 and is fully behind the respective wall section  20  in the embodiment of FIG. 2, for added security purposes. The chain  30  is also attached to the security gate  12  and security gate drive mechanism slightly differently as explained in more detail in regard to FIGS. 3 and 4.  
         [0016]    Turning now to FIG. 3 (Prior Art) there is shown in more detail a security gate drive mechanism  26  for the embodiment of FIG. 1, as it would appear from a view facing away from the wall section  20  shown in FIG. 1. The security gate drive mechanism has a chain drive sprocket  40 , which engages the drive chain  30  after it passes around a first chain guide  42 . The chain subsequently passes around a second chain guide  44 , as shown in FIG. 3. As also shown in FIG. 3 the chain  30  is attached to the sliding gate  12  by an attachment mechanism  32 . The attachment mechanism  32  includes an attachment bar  34 , which is attached to the sliding gate  12  as shown in FIG. 3, e.g., by welding the attachment bar  34  to the sliding gate  12  in the position shown in FIG. 3. The attachment mechanism  32  is described in more detail below in regard to FIG. 7.  
         [0017]    Turning now to FIG. 4 (Prior Art) there is shown a view of the sliding gate  12  when it is at the opposite end of its travel. The sliding gate  12  is shown in FIG. 4 to be attached to the drive chain  30  by a gate extension arm  50 , to which is attached a mounting bar  52 , e.g., by welding to the gate extension arm  50 . The gate extension arm  50  is itself attached to the sliding gate  12 , e.g., by welding the extension arm  50  to the sliding gate  12  in the position as shown in FIG. 4. The drive chain  30  is in turn connected to the mounting bar  52  by a chain attachment mechanism  54 , which is held on the mounting bar  52  by a nut  56 . The extension arm  50  is cut to a particular size or welded along the lower horizontal portion  12 ″ of the frame of the sliding gate  12  such that the chain is relatively taught when the sliding gate  12  is at the extent of its travel, as shown in FIG. 4, and thereafter the chain attachment mechanism  32  and  54  can be threaded through the respective attachment bar  34  and/or  52  to fully tighten the chain before engaging the chain to the respective chain attachment mechanism  32  and/or  54 .  
         [0018]    Turning now to FIG. 5 (Prior Art) there is shown a security gate drive mechanism  26  of the type shown in the embodiment of FIG. 2. Here the drive chain  30  passes over the drive sprocket  40  and around only the first pulley  42 . One end of the drive chain is attached to the sliding gate by an attachment bar  52 , which is attached to the sliding gate  12 , as by welding the attachment bar  56  to the sliding gate  12 , through an attachment mechanism  54  having a nut  56 . The other end of the chain  30  passes around a sprocket  68  rotatably mounted on a sprocket block  66 , which is in turn mounted to a sprocket block post  58 , e.g., by welding the sprocket block  66  to the sprocket block post  58 . The sprocket block post  58  is in turn mounted to the lower horizontal frame member  12 ″ of the sliding gate  12 , as by welding the sprocket block post  58  to the lower horizontal frame member  12 ″ at such a location that the chain is taught in its extension over the sprocket to the mounting bar  34 , to which it is attached by chain attachment mechanism  32 .  
         [0019]    Turning now to FIG. 6 (Prior Art), there is shown an exploded view of a security gate drive mechanism  26 , as shown in FIG. 1 or FIG. 2. The security gate drive mechanism  26  has a frame  72 . As shown in FIG. 6, the pulley wheels  42 ,  44 , which can be, e.g., slotted UHMW rollers adapted to prevent chain slippage off of the drive sprocket  40 , by keeping the drive chain  30  on the chain guide wheels  42 ,  44  in their respective slots in alignment with the drive sprocket  40  during operation. The drive chain  30  can be, e.g., a #41 chain. As shown, the pulley wheels  42 ,  44  are attached to the frame  72  by respective stationary axels  70 , each having a threaded end attached to a respective nut  71 , which may be attached to the frame  72 , as by welding to the frame  72 . The respective chain guide wheels  42 ,  44  are held in place on the respective axles  70  by a washer  74  and a capped nut  76 .  
         [0020]    The security gate drive mechanism of the prior are can include, e.g., a motor  80 , which can be, e.g., a one-half horse power instant reversing 120 VAC, 4 amp, 1625 rpm, parking gate motor, such as that made and sold by Leeson, Model No. 100741.50, which can include high speed ball bearings for smoother and quieter operation. In the alternative, the motor  80  can be a permanent magnet 12V DC motor, e.g. that made and sold by Tru-Torq, Model No. 970-535. The motor  80  has a drive shaft, not shown, that connects to a sprocket wheel  84 , which is part of a sprocket transfer unit  82 . The sprocket transfer unit  82  also has a second sprocket wheel  86 , and a chain or a drive belt  87 , which extends around the sprocket wheels  84  and  86 . The sprocket transfer unit  82  has a typical ratio of 1:1 but the ratio may vary accordingly to match the speed of the motor to the desired speed of the moveable gate. A chain shield  88  covers the sprocket wheels  84  and  86  and the chain  87 . The sprocket wheel  86  is attached to an input shaft  92  of a reduction gear  90 , which also has an output shaft  94 . The reduction gear can be, e.g., a 30-1 worm gear reducer with the gears operating in an oil bath, such as that made and sold by Hampton, Model No. M008. Attached to the output shaft  94  of the reduction gear  90  is the chain drive sprocket  40  and a smaller sprocket  96 , internally mounted on the output shaft  94  in relation to the chain drive sprocket  40 .  
         [0021]    The inner sprocket  96  is connected by a drive chain  98  to a sprocket wheel  100 , which is attached to the end of a limit control spindle  102 , having threads  110 . Moveably mounted on the threads  110  of the motion limit controller spindle  102  is a pair of traveling nuts  112  and  114 . The limit controller spindle  102  is rotatably mounted in a motion limit controller housing  116 , which is in turn attached to the frame  72 . Slideably mounted on the spindle  102  are a pair of adjustably positionable stop members  118  and  120 , which are electrically connected to a controller on a circuit board  132  and can provide a signal indicating that the drive chain  30  has reached one end or the other of its extent of desired motion, as by contact of one or the other of the traveling nuts  112  or  114  with its respective stop member  118  or  120 .  
         [0022]    Also shown in FIG. 6 is a controller circuit board housing  130 , which is attached to the frame  72  and in which is contained the controller circuit board  132 . A cover  134  is attached to the housing  130  and spacers  142 , seat the controller circuit board  132  against input/output electrical signal connections  146  by virtue of being screwed into mounting screws  144 , connected to the interior wall of the housing  130 .  
         [0023]    Turning now to FIG. 7 (Prior Art), there is shown in more detail the connection of the drive chain to the sliding gate, such as in the embodiments of FIGS. 1 and 3. The chain attachment mechanism  32  has a threaded shaft portion  64 , which is threaded into nut  62  after passing through a hole in the attachment bar  34 . The chain attachment mechanism  32  has a flattened attachment extension  60 , to which the chain  30  is attached by passing the pin of the last link of the chain through an opening in the extension  60 .  
         [0024]    It is also well known in the prior art that the motor  80  of a security gate operating system  10  can come with an internal fan and/or an external fan can in addition be supplied, each of which are in operation whenever the motor  80  is in operation.  
         [0025]    Turning now to FIG. 8 and FIG. 9, there is shown perspective views of a security gate driving mechanism according to the present invention. Mounted on the frame  72  is a switched reluctance motor  200 , such as that made for use in industrial sized washing machines, e.g., Neptune washing machines, e.g., one made by Emerson Electric, Model No. M-10816. Such a motor  200  is a type of switched reluctance motor, with the stator and rotor of the motor  200  resembling that of a variable reluctance step motor. Both the stator and rotor (not shown) of the switched reluctance motor  200  have salient poles with phase coils mounted around diametrically opposite stator poles. Power delivered through cables  210  are switched by a controller, not shown, to provide energy to the stator coils of the motor  200  in a fashion that rotates the magnet field through the salient poles of the stator. The rotor will align  
         [0026]    itself to the magnetic field when diametrically opposed stator pole windings are energized. Some of the rotor poles will be aligned and some will be out of alignment with the remaining unaligned stator poles. When the magnetic field in the stator is stepped/rotated to the next stator pole pair, these will attract the unaligned rotor poles and sequentially continuing to perform this stepping/rotating of the magnetic field will result in the rotor continually moving to try to align itself (“catch up”) to the appropriate minimum reluctance position of the energized stator pole windings, thus the term “switched reluctance.” When the rotor is out of alignment to the minimum reluctance position of the energized stator pole windings, the inductance of the windings is proportionally less than maximum inductance to the misalignment thus allowing more current to flow in the windings and creating higher torque. The attainable torque produced is theoretically limited only by the available energy supplied by the controller. Utilization of such a motor  200  provides for very high starting torque as opposed to AC or DC motors. In addition both speed and torque control are more readily managed through the controller supplying power to the stator windings in an appropriate sequence and with appropriate timing, which also makes for similar control properties in both the opening direction movement of the security gate  10  and the closing direction of the security gate  10 . As can be seen from FIG. 8, utilization of a switched reluctance motor  200  also eliminates the need for a reduction gear  90  necessary with AC or DC motors. The drive sprocket  40  can be directly mounted on the shaft  208  of the motor  200 , eliminating a number of pieces of machinery from the prior art security gate drive mechanism, in addition to the reduction gear, and making the space needed much smaller and maintenance more simple. The rotor of the motor can be provided with power in a sequence and timing to achieve the torque and speed relationships required to operate a security gate. This type of drive motor  200  can be utilized with other forms of security gate drive mechanism, e.g., rotary arm drive mechanism, with, e.g., the rotary arm or one of a plurality of pivotally attached rotary arms attached directly to the shaft  94  of the motor  200 , which, of course, can be mounted with the shaft  94  extending generally vertically. While the preferred embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various modifications, in addition to those mentioned above, may be made in these embodiments without departing from the spirit of the present invention. Such modifications, might include the operation of a gate that is hingedly attached for swinging motion between a closed position and an open position, or a gate that is chain driven, but, e.g., opens vertically, as, e.g., a roll-up door commonly used for garage openings and the like. For that reason, the scope of the invention is set forth in the following claims:

Technology Classification (CPC): 4