Patent Publication Number: US-7211001-B2

Title: Personal protection system

Description:
TECHNICAL FIELD 
     The present invention relates to a deterrent or self-defense device which is stored in an environment and, in some situations, becomes a functional part thereof. More particularly, the device is configured such that, when stored, it blends in with the environment and becomes part of the background such that its potential for self-defense use is not noted by others. 
     BACKGROUND OF THE INVENTION 
     There are a variety of personal protection devices which are currently available which disguise a self-defense device in another object which has separate utility; the disguise is intended to provide the user with the advantage of surprise if attacked, since an aggressor will hopefully assume the user to be unarmed. Examples of such disguised devices are canes/umbrellas and dumbbells. However, these devices are freestanding and the conventional objects that these devices resemble are objects that provide a degree of defense use. Canes, for example, have frequently been used to ward off an aggressor, and the weight and mass of a dumbbell serves as an extension of the hand and makes the hand a more effective fighting tool when gripped. Thus, the advantage of surprise is greatly diminished, since an attacker will appreciate that a cane or dumbbell may be used as an improvised weapon and will plan their attack accordingly. 
     Furthermore, these devices most likely can only be used as a defense device if they are being carried by the user at the time an aggressor makes their advance. An aggressor would be quick to the thwart a person from moving to and picking up any device which the attacker would appreciate could be used as a defensive aid. 
     Thus, there is a need for a defensive device which can be concealed in the environment which surrounds the user, readily accessible by the user but the presence of which will not be recognized by an aggressor. 
     SUMMARY OF THE INVENTION 
     The present invention is for a personal protection system to assist a user in warding off an aggressor when the aggressor enters the surroundings where the user is operating. The personal protection system has an elongated shaft and a pair of end bases in which the shaft can be removably engaged, the personal protection system mounting to a surface of the surroundings in which the user is operating and being configured to appear as a natural part of the surroundings. The end bases and the shaft are configured such that, when the shaft is engaged with the end bases, the shaft appears to be a conventional fixture such as a grab bar or a hand rail that one might expect to find in that location. For example, when such a personal protection system is intended for use in a bathroom environment, it could take the form of a shower curtain rod, a towel rack, or a safety bar for incorporation into a shower or tub enclosure. For other applications, the shaft and bases might form part of a grab bar or a handrail for a boat, a bus, an airplane, a kitchen or galley, a hallway, or a gymnasium. 
     The shaft of the personal protection system has a longitudinal shaft axis, a first end portion that is adapted to be held by a user, and a second end portion adapted to form a prod. The shaft itself can serve as a club or truncheon, with the blunt end having utility as a prod. Having a pointed end will enhance its effectiveness, and having a cutting or piercing end will further serve to deter an aggressor. 
     In the case where the prod is designed to puncture the aggressor, it is preferred that the second end portion be provided with a syringe for injection of a bio-toxin, defined herein as a chemical agent which can impair or incapacitate a person to whom the agent is applied so as to prevent further aggressive action by that person. 
     It is frequently desirable to employ prods that are more aggressive than prods that have contact ends for applying pressure to cause discomfort, but which are less aggressive than prods with piercing or cutting surfaces. Such prods include those which employ an appliance for providing a deterrent. Typical examples of such appliances include means for projecting chemical deterrents such as pepper sprays, gases or gels, and devices for generating an electrical discharge. In such embodiments, the shaft is provided with means for housing the appliance, means for communicating the deterrent through and beyond the second end portion of the shaft, and means for activating the deterrent. 
     When a chemical agent is used as a deterrent, the agent is frequently released from a canister through a nozzle when a nozzle release mechanism is activated, the agent being generally directed along a nozzle axis. When such a canister is employed, the shaft includes a chamber that houses the canister, the chamber preferably being aligned with the shaft axis and positioned in the vicinity of the second end portion of the shaft. The chamber terminates with a second end block that is configured to engage the nozzle. The second end block also has a block passage configured to communicate with the nozzle such that the chemical agent released from the nozzle will be directed through the block passage. To aid the user in directing the chemical agent at the aggressor, it is preferred to provide means for maintaining alignment of the nozzle axis with the shaft axis. When the nozzle is axially aligned with the canister, means for maintaining the alignment of the nozzle axis with the shaft axis can be provided by employing a canister that slidably engages at least a portion of the chamber. When only a portion of the chamber is sized to match the canister, the chamber may have a conical ramp surface to guide the canister into the portion which is matched in size, and the canister can be further aligned by providing a concave conical rear surface of the chamber for engagement with the canister. 
     When a canister such as described above is employed, means for activating the nozzle release mechanism are provided. Typically, the chemical agent is released when there is axial motion of the nozzle with respect to the canister. In such cases, the means for activating the nozzle mechanism is preferably provided by means for moving the chamber rear surface, thereby advancing the canister in the chamber toward the second end block while the engagement of the nozzle with the second end block serves to maintain the nozzle in position. Advancement of the canister is preferably accomplished by providing a slidably engaged activating rod having a head that defines the chamber rear surface. In a preferred embodiment, the activating rod has a free end that extends through the first end portion of the shaft so as to be manually operated. 
     When the deterrent appliance provides an electrical discharge, the second end portion of the shaft incorporates a pair of electrodes and an electrical discharge circuit for generating a high voltage therebetween. The electrical discharge circuit, in turn, is powered by a battery, both these elements being housed in the shaft. The electrodes extend through and protrude from the second end block and serve as means for communicating the deterrent. A switch in the first end portion of the shaft provides the means for activating the deterrent. In this location, the switch is positioned so that it is concealed when the shaft is engaged in the end bases. 
     The pair of end bases of the personal protection system include a first end base for attachment to the surface of the surroundings. The first end base has a first base aperture configured to accept the first end portion of the shaft. A second end base is also provided, for attachment either to the same surface as the first end base or to another surface of the surroundings. The second end base has a second base aperture configured to accept the second end portion of the shaft; thus, the first end base and the second end base should be mounted such that the base apertures face each other and are aligned to accept the shaft. To assure that the countermeasure system is not recognized by an intruder/aggressor, the shaft, the first end base and the second end base are configured so as to form a natural-appearing extension of the surface when the end portions are accepted in the base apertures, so as to become part of a background in which the user is operating. 
     Means for engaging and disengaging the end portions of the shaft in the first end base and the second end base are provided. These means are designed such that, when so engaged, the shaft and the bases transition so as not to interrupt the continuity of the background. It is preferred that the shaft and bases should function in the same manner as the background fixture which they resemble. For example, when the shaft and bases provide the appearance of a safety bar or handrail, the shaft should securely engage the bases so that the combined shaft and bases can function as a safety bar or handrail to provide support when grasped by the user. To accomplish this functionality, it is preferred to provide means for lockably engaging at least one of the end portions with its associated base. When the shaft is lockably engagable with one of the end bases, the end base is preferably configured so as to conceal the means for lockably engaging the shaft. 
     The means for engaging and disengaging the shaft in the end bases allow the shaft to be removed by deliberate action on the part of the user. Typically, the shaft is advanced further into one of the base apertures to allow the other end to be freed from its associated base aperture; the shaft can then be disengaged from the base into which it was advanced. Frequently, one of the end portions of the shaft is pivotable when accepted into the corresponding base aperture, allowing the other end portion to be swung past its associated end base when the shaft is advanced. Alternatively, the shaft may have sufficient flexibility to allow the other end to be bent away from its associated end base. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a section view of a public transit vehicle, such as a subway car, wherein two personal protection systems are formed by vertical bars and associated bases that provide stabilizing support for standing passengers. 
         FIG. 2  is an isometric view of one the shafts and associated bases shown in  FIG. 1 . 
         FIG. 3  is an exploded isometric view of the shaft and bases shown in  FIG. 2 . In this embodiment, the shaft has a first end portion which is knurled to provide a gripping surface, and a second end portion which is formed with a pointed tip so as to prod a potential aggressor, thereby turning away the aggressor&#39;s advances. 
         FIG. 4  is an isometric view of a second end portion of a shaft of an aggressive personal protection system which prods the aggressor with a blade that is capable of piercing and cutting the aggressor. 
         FIGS. 5 and 6  are isometric views of another aggressive personal protection system of the present invention, where an invasive prod is employed and is mounted in the second end portion of the shaft. In this embodiment, a needle and an associated syringe are provided. The syringe can be filled with a bio-toxin which can be injected into the aggressor. 
         FIG. 7  is a section view of a shaft of another embodiment of a personal protection system of the present invention, which is more aggressive than the contact prod shown in  FIGS. 2 and 3 , but less aggressive than the invasive prods of the embodiments illustrated in  FIGS. 4-6 ; in this embodiment, the shaft has a second end portion that houses a canister of a chemical spray irritant to inhibit the advance of an aggressor. The irritant is released from the canister as it is moved toward the second end portion of the shaft by an activating rod that extends along the shaft and through a first end portion of the shaft. In this embodiment, alignment of the canister and nozzle with the shaft is maintained by the use of a canister that slidably engages a chamber in the second end portion. 
         FIG. 8  is an isometric view of an alternative embodiment to that of  FIG. 7  that performs the same function, but which employs a shaft that is fabricated from a tube rather than from a solid bar having a cavity formed therein. The tube which serves as the shaft has, in its second end portion, a second end insert configured to be slidably inserted into the shaft and, in turn, to slidably engage the canister of chemical deterrent. A second end block having a block passage is threaded into the second end insert and can be removed to replace the canister. A first end insert is also slidably inserted into the tube, and has a rod passage configured to slidably engage and support the activating rod. 
         FIG. 9  is an isometric view of a shaft which shares many parts in common with the shaft shown in  FIG. 8 , but which has a second end block configured to provide alignment for a smaller diameter canister of chemical deterrent; alignment of the canister and the nozzle is provided by a chamber support surface on the second end block, which is configured to define a portion of the chamber that is sized to be slidably engaged by the canister, in combination with a conical chamber rear surface formed on an activating rod.  FIG. 9  also shows two alternative second end blocks which can be employed; one second end block provides a tip point which provides sharp edges capable of cutting the aggressor if jabbed or slashed with sufficient force, while another second end block provides a pointed tip as well as serving to align a canister of chemical deterrent. 
         FIG. 10  is a section view of a shaft of another embodiment of the present invention, which is similar to the embodiment shown in  FIG. 7 , but where the canister is loaded with a gel irritant, rather than a liquid or gas. In this embodiment, alignment of the canister and nozzle is maintained by a chamber support surface and an essentially conical chamber rear surface so as to align the nozzle and canister with the shaft. A laser aiming device is provided in the second end block, and generates a light beam which is parallel to a longitudinal shaft axis of the shaft to aid the user in aiming the gel spray at a target. 
         FIG. 11  is an isometric view of a shaft fashioned after the shaft shown in  FIG. 10 , but using the insert shown in  FIG. 8 . 
         FIG. 12  is an isometric view showing a shaft that forms part of another embodiment of a personal protection system of the present invention. In this embodiment, a second end portion of a shaft is designed to prod the aggressor by providing an electrical discharge to shock the aggressor. 
         FIG. 13  is a section view of a shaft of another embodiment of the present invention, which combines the deterrent devices of the embodiments shown in  FIGS. 7–11  and  FIG. 12 ; the shaft employs a chemical spray as a primary deterrent, but also includes an electrical discharge device to provide a supplemental deterrent to be employed after the canister has been activated. In this embodiment, the canister is advanced by a solenoid. A power source and circuitry for controlling both the solenoid and the electrical discharge circuit in response to a switch are contained in the shaft. 
         FIG. 14  is an exploded view of a portion of another embodiment of the present invention, where one of the end bases has a deformable sidewall which embraces the shaft and allows it to be tilted out of alignment with the other base, as indicated in phantom. Slots in the deformable wall further facilitate removal of the shaft. 
         FIG. 15  is an exploded view of a portion of another embodiment of the present invention, where one of the end bases has a “U” shaped opening to allow the shaft to be swung out of engagement with the other end base. 
         FIG. 16  is a section view of a portion of another embodiment of the present invention, where one of the bases has a ring which engages a corresponding end portion of the shaft so as to restrain the shaft but to allow it to pivot so that the shaft can be swung out of the other base. 
         FIG. 17  is a section view of a portion of another embodiment, which employs a shaft end portion and a corresponding base that are functionally similar to those shown in  FIG. 16 . In this embodiment, the end portion of the shaft is provided with a ring which engages a corresponding aperture in the base so as to restrain the shaft but allow it to be swung in and out of engagement with the other base. 
         FIG. 18  is a partial view of another embodiment of the present invention; in this embodiment, one end portion of the shaft is threadably engaged with a corresponding end base. When the threads are tightened, the shaft is securely fitted in the base; however, the shaft could be loosened in service if used as a grip bar. In this embodiment, the shaft is locked to the base by a spring-loaded pawl which engages a toothed profile of the shaft which is configured so as to allow the shaft to be turned only in the direction to tighten the threadable engagement. The pawl can be retracted by a servo to allow the shaft to be loosened. A remote hand-held bob, similar as to those used to lock and unlock automobile doors, can be used to control the servo. 
         FIG. 19  is a partial isometric view of another embodiment of the present invention where a bayonet coupling is used to secure a shaft in one of the bases, thus allowing quick release of the shaft without the shaft being subject to inadvertent loosening. 
         FIG. 20  is a partial view of an alternative bayonet-type mounting which can be employed where reduced protrusion of the shaft into the base is desired. 
         FIG. 21  is a perspective view illustrating one embodiment of a personal protection system of the present invention, where the personal protection system serves as a hand rail such as is frequently provided on a bus. In  FIG. 21 , the hand rail is shown mounted in an airplane cabin and is positioned to blend in with the airplane cabin environment. 
         FIG. 22  is an isometric view showing an embodiment of the present invention where the countermeasure is installed in a shower stall and, in general service, serves as a safety bar. 
         FIG. 23  is an elevation view showing an embodiment of the present invention where the countermeasure system is installed on a boat and in, general service, serves as a grab rail. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a schematic section view of a public transit vehicle  10  such as a subway car, commuter train car, or a bus which is fitted with a pair of personal protection systems  12  of the present invention. The personal protection systems  12  provide vertical shafts  14  which, in normal service, provide grab bars and thus blend into the environment where public transit personnel are working. The vertical shafts  14  are in turn each mounted in a first end base  16 , which serves as a lower base, and a second end base  18 , which serves as an upper base. The end bases ( 16 ,  18 ) attach respectively to a floor surface  20  and to a ceiling panel  22  of the vehicle  10 . The personal protection systems  12  are not only a natural part of the environment inside the public transit vehicle  10 , but also provide a support function to passengers. This is done while still allowing a conductor or other public transit personnel to remove one of the shafts  14  from the associated bases ( 16 ,  18 ) and use the shaft  14  as a deterrent to a ward off an aggressor. When the vertical shafts  14  are to be employed by riders to provide support when standing, it is critical that means be provided to avoid loosening of the shafts  14  in service; such means are discussed below. It may also be that catches can be provided that could only be released by service personnel; for example, one option might be an electromagnetic catch that could be remotely operated by authorized personnel, such as by a radio-activated device or a wired controller. Also, hand-held devices similar to the bobs carried on key chains for locking and unlocking automobile doors might be used, as discussed below with regard to  FIG. 18 . 
       FIGS. 2 and 3  illustrate one of the personal protection systems  12  shown in  FIG. 1  in greater detail.  FIG. 2  is a view of the assembled personal protection system  12 , while  FIG. 3  is an exploded view. In this embodiment, the shaft  14  has a first end portion  24  which is designed to be gripped by the user when being used to fend off an aggressor. Preferably, the first end portion  24  has a gripping surface  26  such as knurling to improve the control of the shaft  14  by the user. The gripping surface  26  should be concealed when the shaft  14  is stored to avoid providing notice that the grab bar differs from conventional bars. A second end portion  28  of the shaft  14  is adapted to form a prod; in this embodiment, the prod is a spear point  30  which can be used to jab at an aggressor. 
     As shown in  FIG. 3 , the first base  16  has a first base aperture  32  which is configured to slidably engage the first end portion  24  of the shaft  14 . The first base  16  terminates in a first base mounting flange  34  which is designed for coupling the floor surface  20  of the public transit vehicle  10  (shown in  FIG. 1 ). 
     The second base  18  has a second base aperture  36  which is configured to accept the second end portion  28  of the shaft  14 . When the first base aperture  32  is configured so as to slidably engage the first end portion  24  of the shaft  14 , then the configuration of the second base aperture  36  must be sufficiently oversized with respect to the second end portion  28  that such that the shaft  14  can be tilted to a sufficient degree that, when advanced into the second base aperture  36  a sufficient distance to free the first end portion  24  from the first base aperture  32 , the first end portion  24  can be moved out of alignment with the first base  16  and slid past it so as to allow removal of the second end portion  28  from the second base  18 . This oversizing of the second base aperture  36  results in a gap G (shown in  FIG. 2 ) between the second end portion  28  and the second base  18 , which creates a somewhat unnatural appearance to the astute observer; this gap can be overcome with more refined embodiments, as is discussed below. Again, the second base  18  terminates in a second base mounting flange  38  which is designed to be attached to the ceiling panel  22  of the public transit vehicle  10  (shown in  FIG. 1 ). 
     In this embodiment, the shaft  14  is locked into position by a pull pin  40  which is designed to pass through a second base passage  42  and a shaft second end passage  44 ; a lock pin  46  is provided to secure the pull pin  40  in the passages ( 42 ,  44 ). While a pull pin is illustrated for lockably engaging the shaft  14  with the second base  18 , it is preferred for the locking means to be concealed to preserve the disguise of the personal protection system  12 ; such concealed locking means are discussed below. 
       FIG. 4  is a partial view of a shaft  50  having a shaft second end portion  52  that is more aggressive than the second end portion  28  discussed above. In this embodiment, rather than using a spear point to be poked at an aggressor, the shaft second end portion  52  is provided with a knife blade  54  to allow the user to slash at the aggressor as well as pierce the aggressor. The knife blade  54  is retractable so that the shaft second end portion  52  can be readily stored in a second end base (not shown). The knife blade  54  is biased by a blade spring  56  so as to extend from the shaft second end portion  52  when the shaft second end portion  52  is withdrawn from the second end base, and is maintained in the extended position by a spring-loaded catch  58  that engages a blade catch passage  60 . To retract the knife blade  54  in order to return the shaft  50  to its stored position engaged with the end bases, a release button  62  on the shaft  50  is pushed to disengage the catch  58  from the blade catch passage  60 , allowing the knife blade  54  to be retracted as the shaft second end portion  52  is inserted into a second base aperture of the second end base. 
       FIGS. 5 and 6  illustrate a section of another shaft  100 , which differs from the shafts  14  and  50  discussed above in that the prod incorporates a syringe  102  and a needle  104  mounted in a second end portion  106  of the shaft  100 . The syringe  102  and the needle  104  are mounted parallel to a longitudinal shaft axis  108 , and reside in a telescoping section  110  of the second end portion  106 . The telescoping section  110 , which slidably engages the syringe  102  as well as a sidewall  112  of the shaft  100 , will collapse when pushed against the body of an aggressor, providing means for mounting the needle  104  and the syringe  102  such that the needle  104  is extendable beyond the second end portion  106 . The collapse has a first stage, where the telescoping section  110  collapses against the pressure of a biasing spring  114  so as to expose a portion of the needle  104 . In order to assure that this occurs without ejecting fluid from the syringe  102 , it is necessary that the resistance of a plunger  116  to sliding in the syringe  102  be substantially greater then the force supplied by the spring  114 . As shown in  FIG. 6 , a second stage of telescoping occurs when the telescoping section  110  contacts a rim  118  on the syringe  102  and pushes the syringe  102  so as to advance the plunger  116  into the syringe  102 , thereby providing means for injecting the contents of the syringe  102  through the needle  104 . Preferably, the syringe  102  contains a bio-toxin which can quickly disable an aggressor. Some examples of substances which might serve as injected bio-toxins would include poisons, sleep-inducing drugs, disorienting drugs, and muscle-relaxing drugs. 
     For many applications, it is desirable for the shaft to employ a prod which is not so aggressive as to puncture the aggressor, but which provides greater deterrent capability than a simple pointed end. For such applications, it is frequently desirable to employ conventional appliances for generating a deterrent. Two examples of such appliances that have been classically used for self-defense and deterring aggression are devices which discharge a chemical irritant and devices which generate a high-voltage electrical discharge. Examples of shafts of the present invention which incorporate such deterrent-generating appliances are described below. 
       FIG. 7  illustrates a shaft  150 , which differs from the shafts ( 14 ,  50 ,  100 ) discussed above in that it has a second end portion  152  that is provided with a chamber  154  for housing a canister  156  filled with a pressurized chemical irritant. The chamber  154  has a sidewall  158  configured to be slidably engaged by the canister  156 . The canister  156  can be sprayed to stop the advance of an aggressor; in this embodiment, the irritant is gaseous when sprayed. The canister  156  has an associated nozzle  160  with a valve (not shown) which is opened when the nozzle  160  is advanced into the canister  156 . The nozzle  160  has a nozzle axis  162  along which the spray is directed. The second end portion  152  terminates at a second end block  164  having a block passage  166  therethrough. In this embodiment, the second end block  164  is formed as an integral part of the shaft  150 . The block passage  166  is symmetrically disposed about a shaft axis  168 . The second end block  164  is also formed with a nozzle seat  170  which abuts the block passage  166  and is configured to engage the nozzle  160  so as to limit its longitudinal motion. The second end block  164  is preferably also formed with a nozzle recess  172  that is configured to accept the nozzle  160  and limit off-axis movement of the nozzle  160 . 
     An activating rod  174  is provided, which has a rod head  176  that is configured to slidably engage the sidewall  158  of the chamber  154  so that it can be brought into engagement with the canister  156 ; a chamber rear surface  178  on the rod head  176  serves to terminate the chamber  154 . An O-ring  180  is provided on the rod head  176  to sealably engage the sidewall  158  to prevent any chemical irritant from blowing back toward a first end portion  182  of the shaft  150 . The O-ring  180  also serves to maintain the rod head  176  axially aligned with the shaft  150 , and should be sized so as to avoid excessive friction against the sidewall  158  to allow the activation rod  174  to be advanced without undue resistance. 
     The activation rod  174  has a rod shank  184  terminating in a rod free end  186  that slidably engages and passes through a first end cap  188  that terminates the first end portion  182  of the shaft  150 . A first end passage  190  in the first end cap  188  is configured to slidably engage and support the rod shank  184  so as to help maintain the activating rod  174  axially aligned with the shaft  150 . A rod retaining ring  192  on the rod shank  184  limits the extension of the activating rod  174  from the first end cap  188 ; the rod free end  186  should not extend beyond the shaft  150  to prevent accidental discharge of the canister  156  when the first end portion  182  is inserted into a first end base (not shown). When the user pushes on the rod free end  186 , the activating rod  174  pushes on the canister  156 ; since the nozzle  160  engages the nozzle seat  170 , it cannot move with the canister  156  and is forced inward, opening the valve to release the irritant spray through the block passage  166 . 
     In this embodiment, the canister  156  can be replaced by removing the first end cap  188 , which is threadably engaged with the first end portion  182 , and removing the activating rod  174 . A new canister  156  can then be inserted into the chamber  154 . The nozzle  160  should be axially aligned with the shaft axis  168  to assure that the spray is directed through the block passage  166 . In this embodiment, axial alignment of the nozzle  160  is achieved by making the sidewall  158  closely sized to the canister  156  to guide it when it is inserted into the shaft  150 . The nozzle recess  172  is preferably chamfered to allow the nozzle  160  to be readily inserted therein. Additionally, the chamber rear surface  178  that applies force to advance the canister  156  should be longitudinally positioned such that the activating rod  174  requires minimal movement to advance the canister  156  to release the chemical agent. Longitudinal positioning of the chamber rear surface  178  can be adjusted by having the rod head  176  threadably mounted to the rod shank  184 , allowing the effective length of the activating rod  174  to be adjusted. 
       FIG. 8  is an isometric view of an alternative embodiment to that of  FIG. 7  that performs the same function, but which employs a shaft  200  that is fabricated using a tube  202  rather than being machined from a solid bar. The tube  202  has a second end portion  204  that is provided with a second end insert  206  having an outer diameter such that it can be slidably inserted in the tube  202 . The second end insert  206  could be press fitted into the tube  202 , but more preferably is secured in the second end portion  204  by an adhesive to reduce the need for precision machining and to accommodate variation in the size of the tube  202 . The second end insert  206  has a chamber sidewall  208  sized such that a canister  210  of chemical deterrent will slidably engage the second end insert  206 . The chamber sidewall  208  defines, in part, a chamber  212  in which the canister  210  is housed. 
     A second end block  214  is provided, having a nozzle seat  216  and a block passage  218 , through which the chemical agent in the canister  210  can be discharged. In this embodiment, the second end block  214  is not formed as an integral part, but instead threadably secures into the second end insert  206 . The nozzle seat  216  is configured to engage a nozzle  220  on the canister  210 , and the second end block  214  is preferably formed with a nozzle recess  222  configured to support the nozzle  220 . Preferably, the threadable engagement of the second end block  214  with the second end insert  206  is such as to resist turning; such can be readily provided by forming the second end block  214  of a plastic which is slightly compressed as it threadably engages the second end insert  206 . The second end block  214  illustrated has a screwdriver slot  224  that can be engaged by a conventional screwdriver to allow the second end block  214  to be unscrewed to provide access to the chamber  212  to replace the canister  210 . The second end insert  206  allows the tube  202  to be relatively thin-walled, since the tube  202  itself is not threaded, without compromising the support function of the shaft  200  when secured in a pair of end bases (not shown). 
     The shaft  200  also has a first end portion  226  which has a first end insert  228  that is inserted into the tube  202  and secured therein, again preferably by use of an adhesive. The first end insert  228  serves to retain and support an activating rod  230  that extends within the shaft  200 . Since the activating rod  230  is closely sized to the tube  202 , it must be inserted into the tube  202  before the inserts ( 206 ,  228 ) are both secured into the tube  202 . Alternatively, an activating rod having an expandable head could be employed. 
       FIG. 9  is an isometric view of an embodiment which shares many parts in common with the embodiment shown in  FIG. 8 , but which is intended for use with a canister  210 ′ which is smaller in diameter than the canister  210 . In this embodiment, a second end block  214 ′ is threadably secured into the second end insert  206 . The second end block  214 ′ is provided with a chamber support surface  232  that extends back so as to form a portion of a chamber  212 ′, and a conical ramp surface  234  configured so as to slip around the canister  210 ′ as the second end block  214 ′ is installed into the second end insert  206 . The ramp surface  234  serves to guide the canister  210 ′ into slidable engagement with the chamber support surface  232 , which in turn forms a portion of the chamber  212 ′ that is sized to engage the canister  210 ′ to maintain it axially aligned. Forming the ramp surface  234  with an angle of about 15° is felt to be effective in guiding the second end block  214 ′ over the canister  210 ′. Further alignment of the canister  210 ′ with the tube  202  is provided by a conical chamber rear surface  236  formed on the activating rod  230 ; the conical configuration of the chamber rear surface  236  acts to center either the canister  210  (shown in  FIG. 8 ) or the canister  210 ′ in the tube  202 . Forming the chamber rear surface  236  with an angle of about 45° is felt to provide an effective centering action. 
     It should be noted that, where the canister  210 ′ differs in length from the canister  210 , the length of the activating rod  230  may need to be adjusted, or a spacer may need to be employed to allow the activating rod  230  to properly advance and thereby activate the canister  210 ′. In the embodiment shown, the tube  202  is fitted with a first end insert  228 ′ which has a first end cap  238  threadably engaged therewith. The first end cap  238  is configured to support and slidably engage the activating rod  230 . 
     The enlarged portion of  FIG. 9  better illustrates the nozzle seat  216  and the nozzle recess  222  of the second end block  214 ′, which are identical to those of the second end block  214  shown in  FIG. 8 . The nozzle recess  222  has a chamfered edge  240  that facilitates insertion of the nozzle  220  thereinto when the second end block  214 ′ is screwed into the second end insert  206 . 
     In addition to adapting the shaft  200  to different sizes of canisters ( 210 ,  210 ′) by employing different second end blocks ( 214 ,  214 ′), the shaft  200  could be adapted to use a different deterrent by providing alternative second end blocks. Two examples are shown in  FIG. 9 . A second end block  214 ″ is configured to threadably engage the second end insert  206 , and is provided with a fluted point  242 . The fluted point  242  provides a spear point, as employed in the shaft  14  discussed above and shown in  FIGS. 2 and 3 , but also provides edges  244  that may provide a cutting and/or slashing capability. Furthermore, if the second end block  214 ″ is sufficiently heavy, it may serve to act as a bludgeon. One heavy material which is durable and provides good edge-holding ability is tungsten carbide. A second end block  214 ′″ combines a fluted point  242 ′ with the elements of the second end block  214 ′ that allow it to form a chamber for the canister  210 ′. The second end block  214 ′″ has a block passage  218 ′ that extends through an apex  246  of the fluted point  242 ′. 
       FIG. 10  illustrates a shaft  250  which is similar to the shaft  150  shown in  FIG. 7 , but which is intended for use with a canister  252  (shown in phantom) that is loaded with an irritant gel. Again, the canister  252  has a nozzle  254  which opens a valve and releases the chemical irritant when advanced into the canister  252 . The shaft  250  has a chamber  256  terminating at a chamber rear surface  258 . A portion of the chamber  256  is defined by a chamber insert  260  which has a chamber support surface  262  and a ramp surface  264 . The chamber support surface  262  defines a portion of the chamber  256  that is sized to be slidably engaged by the canister  252 , so as to maintain the canister  252  aligned with a shaft axis  266  of the shaft  250 . The ramp surface  264  acts to guide the canister  252  into alignment with the chamber support surface  262  when the canister  252  is inserted into the shaft  250 . The canister  252  is also engaged and aligned by the chamber rear surface  258 , which forms part of an activating rod  268  that serves to advance the canister  252  in the chamber  256 . Again, the chamber rear surface  258  is concave when viewed from the chamber  256 , and is preferably conical. It should be appreciated that other concave, symmetric surfaces could be employed, such as spherical surfaces. The chamber rear surface  258  is both concave and symmetric about the shaft axis  266  so as to engage the canister  252  to maintain the canister  252  aligned with the shaft axis  266  to facilitate aiming the spray from the nozzle  254 . 
     While the use of a gel allows greater range, the increased range is due largely to reduced spread, which makes accurate targeting of the aggressor critical. To aid the user in targeting the aggressor, the shaft  250  houses a laser aiming device  270  that directs a beam of light  272  parallel to the shaft axis  266  and the direction of the stream of the gel so as to indicate the targeted region. The energy to operate the laser aiming device  270  is provided by a laser power circuit  274  which is powered by a battery  276 , both of which are housed in the activating rod  268 , which in turn is configured to slidably engage a sidewall  278  of the shaft  250 . The activating rod  268  has a rod free end  280  which extends from a first end cap  282  which closes a first end portion  284  of the shaft  250 . The rod free end  280  in turn is fitted with a pushbutton switch  286  that provides power from the battery  276  to the laser power circuit  274  to generate the beam of light  272  before the rod free end  280  is depressed so as advance the canister  252  and release a gel stream. Depressing the switch  286  causes the laser aiming device  270  to be activated, which may serve as sufficient deterrent to the aggressor since such aiming devices are frequently associated with firearms. If not, applying further pressure to the switch  286  causes the activating rod  268  to move, causing a stream of gel to be released from the canister  252 , with the laser aiming device  270  allowing the user to readily see where the stream of gel is aimed. 
       FIG. 11  is an isometric view of a shaft  300  which shares many parts in common with the shaft  200  shown in  FIGS. 8 and 9 , but which is adapted to provide the functions of the shaft  250  shown in  FIG. 10 . In this embodiment, the shaft  300  is again formed using the tube  202  and the second end insert  206 . However, the shaft  300  employs a second end block  302  which has a laser aiming device  304  incorporated therein. In this embodiment, the laser aiming device  304  is self-contained, having a switch stem  306  which extends into a chamber  212 ″ when the second end block  302  is threadably secured into the second end insert  206 . When the switch stem  306  is depressed, it provides power to the laser aiming device  304  from button cell batteries (not shown) that are also housed in the second end block  302 . The batteries are retained by a battery cover  308  which is threadably attached to the second end block  302 . 
     The laser aiming device  304  is positioned such that advancement of a canister  210 ″ of irritant gel by the activating rod  230  causes the canister  210 ″ to depress the switch stem  306 , activating the laser aiming device  304 . Preferably, activation of the laser aiming device  304  occurs before the canister  210 ″ has been advanced sufficiently to open the valve to release the gel from the canister  210 ″. 
       FIG. 12  is an isometric view that illustrates a shaft  350  that differs from the shafts ( 14 ,  50 ,  100 ,  150 ,  200 ,  250 , and  300 ) discussed above, in part, in that the shaft  350  houses an appliance for generating an electrical deterrent. A second end portion  352  of the shaft  350  has a pair of spaced apart electrodes  354  extending therefrom. These spaced apart electrodes  354  pass through a second end block  356  and are connected to an electrical discharge circuit  358  which is housed in a central passage  360  of the shaft  350 . Batteries  362  are also housed in the central passage  360  and connect to a switch  364  mounted so as to be exposed at a first end portion  366  of the shaft  350 . When the switch  364  is closed by pressure applied by the user, power is provided from the batteries  362  to the electrical discharge circuit  358 , which in turn generates a cyclic high voltage across the electrodes  354 . The high voltage acts to disable the motor functions of the person contacted by the electrodes  354 , so as to prevent that person from continuing any aggressive action. An arcing potential is sustained across the electrodes  354  while the switch  364  is depressed. It should be appreciated that a shaft having the function of the shaft  350  could be formed using the tube  200  and the second end insert  206  shown in  FIGS. 8 ,  9 , and  11 , simply by providing different internal elements attached to a suitable second end block which threadably engages the second end insert  206 . It should also be pointed out that, while disposable batteries are illustrated, the batteries  362  could be provided by one or more rechargeable batteries, in which case the shaft could be designed to allow the batteries to be recharged when the shaft is stored in the end bases. 
       FIG. 13  illustrates a shaft  400  which employs a chemical irritant spray in combination with a supplemental means for deterring an aggressor in the event that the chemical spray is not sufficient or misses its intended target. An irritant spray canister  402  with a nozzle  404  resides in a chamber  406  and is aligned with a shaft axis  408  in a manner similar to that employed in the embodiment shown in  FIG. 10 . In this embodiment, the canister  402  is advanced by a solenoid  410  which has an extendable activating rod  412  that engages the canister  402 . In the event that the spray has been exhausted and the aggressor has not been turned away, then a supplemental deterrent is supplied by a pair of spaced apart electrodes  414  connected to an electrical discharge control circuit (which is not shown in  FIG. 13 ). The electrodes  414  bracket a block passage  416  that communicates with the nozzle  404  and are positioned so as not to interfere with release of the spray from the nozzle  404 . The solenoid  410  and the electrodes  414  are powered by batteries  418  (only one of which is shown) housed in the shaft  400 . A two-stage pressure switch  420  is provided; when pressure is applied by the user, the switch  420  provides power first to the solenoid  410 , then, with increasing pressure, to the electrodes  414 . The use of the solenoid  410  allows the possibility of providing a remote cut-off device which would deactivate the shaft  400  to prevent use by unauthorized persons. 
     The following figures illustrate details of the interaction between the shaft and the end bases in several exemplary embodiments, this interaction providing the means for engaging and disengaging the shaft in the end bases. Typically, the engagement of one of the end portions with its associated end base allows the end portion to pivot slightly with respect to the end base. While such can be provided by making one of the base apertures oversized, as discussed above with regard to  FIGS. 2 and 3 , it is preferred for the end portion and the end base to provide a natural appearance, without unsightly or atypical gaps which might alert an observer to the fact that the disguised personal protection system is not simply a conventional object. 
       FIG. 14  is an exploded isometric view of a personal protection system  500 , which illustrates a second end base  502  having a flange  504  with a sidewall  506  attached thereto and configured to slidably engage a second end portion  508  of a shaft  510  which bears many similarities to the deterrent device illustrated in  FIGS. 2 and 3 . However, in this embodiment, the sidewall  506  is formed of an elastically deformable material that allows the shaft  510 , when advanced further into the second end base  502 , to be swung as shown in phantom. This motion allows a first end portion  512  of the shaft  510  to be swung out of alignment with a first end base  514  so that the first end portion  512  of the shaft  510  will clear the first end base  514 ; this in turn allows the second end portion  508  to be withdrawn from the second end base  502 . Having an elastically deformable sidewall  506  eliminates the need to provide a gap G such as is employed in the embodiment illustrated in  FIGS. 2 and 3 . Slots  516  can be provided in the sidewall  506  to allow greater deformation of the sidewall  506  to help assure that the second end portion  508  of the shaft  510  can be tilted in the second end base  502  sufficiently to move the first end portion  512  out of alignment with the first end base  514 . While the deformability of the sidewall  506  allows removal of the shaft  510  without the need for a large gap between the shaft  510  and the sidewall  506 , employing the slots  516  may again create an abnormal appearance. A pull pin  518  passes through a shaft passage  520  and a base passage  522  and serves to secure the shaft  508  in the bases ( 502 ,  514 ) until needed. 
       FIG. 15  illustrates another means for engaging and disengaging an end portion  550  of a shaft  552  with a base  554 , which again allows the end portion  550  of the shaft  552  to be tilted in the base  554  to aid in removal. In this embodiment, the base  554  has a “U” shaped opening  556  that opens a portion of a base aperture  558 . The “U” shaped opening  556  allows the shaft  552  to be advanced further into the base aperture  558  and then readily pivoted out of engagement with the other end base (not shown) when a pull pin  560  is removed. 
       FIG. 15  also illustrates an ejection spring  562  which can be housed in the end base  554  to aid in removing the end portion  550  once the other end portion has been swung out of alignment with its associated end base. The ejection spring  562  provides a biasing force that tends to push the end portion  550  out of the base aperture  558 . 
     It should be appreciated that another approach to provide a more natural appearance can be achieved if the shaft itself is sufficiently flexible that the first end portion can be bent out of alignment with the first end base even if the second end base is rigid. Such flexibility of the shaft is particularly feasible when the shaft is formed from relatively thin-walled tubing, such as the tube  202  shown in  FIGS. 8 ,  9 , and  11 , and has the advantage that the end bases can have a more conventional appearance. 
     While the use of flexible or deformable materials as discussed above can provide a more natural appearance for the personal protection system, in some applications it may be desirable to use rigid materials to assure that the personal protection system provides sufficient support for users.  FIG. 16  is a section view illustrating another means for engaging and disengaging an end portion  600  of a shaft  602  with an end base  604  in such a manner as to allow the end portion  600  to be tilted in the base  604  to bring the other end portion (not shown) out of alignment with its associated end base in the same manner as is illustrated in  FIG. 14 ; however, in this embodiment the shaft  602  and the end base  604  can be rigid. The base  604  of this embodiment has a base aperture  606  that is larger in diameter than the end portion  600  of the shaft  602 . To prevent a readily visible gap, an inwardly-directed ring  608  is provided to fill the space between the base  604  and the shaft  602 . The ring  608  creates a reduced diameter D R  of the base aperture  606 , while the remainder of the base aperture  606  has a larger diameter D A . The end portion  600  has a shaft diameter D S  which is only slightly less than the reduced diameter D R , allowing the ring  608  to snugly engage the end portion  600 . This provides support for the shaft  602  as well as helping to disguise the fact that the shaft  602  is removable. When the shaft  602  is slid upwards so as to disengage the other end portion from its associated end base, the larger aperture diameter D A  of the base aperture  606  allows the shaft  602  to then be tilted (as shown in phantom) until the other end portion is no longer aligned with its associated end base. The shaft  602  can then be slid out of engagement with the base  604 . 
       FIG. 17  is a section view of a portion of another embodiment, where an end portion  650  of a shaft  652  is provided with an outwardly-protruding ring  654  which engages a corresponding base aperture  656  of a base  658 . The ring  654  allows the base  658  to supportably engage the shaft  652 , while allowing the shaft  652  to be swung in and out of the base  658  in a manner similar to that discussed above for the embodiment shown in  FIG. 16 . 
     As discussed above, it is preferred for the personal protection system to have the appearance of a conventional fixture. Thus, when the shaft is to be lockably engaged with the end bases, it is preferred for the end bases to be configured so as to conceal the locking means, thereby providing a more natural appearance than is achieved using pull pins, such as those shown in  FIGS. 2 ,  3 ,  14 , and  15 . The following figures illustrate some examples of concealed locking means which could be employed to secure one end of a shaft in a base; these means would be well suited for use in combination with one of the pivotable engagement schemes discussed above at the other end of the shaft. 
       FIG. 18  illustrates a means for engaging and disengaging an end portion  700  of a shaft  702  with an end base  704  which provides a lockable engagement where the locking elements are not apparent when the shaft  702  is secured to the end base  704 . The end portion  700  has a shaft threaded section  706 , while the end base  704  has a base sidewall  708  with a sidewall threaded section  710  configured to threadably mate with the shaft threaded section  706 . The threading should be relatively coarse so as to allow a quick release. When the shaft  702  is to serve a support function, then it is preferred to have a mechanical lock that needs to be released before the shaft  702  can be turned in a direction so as to loosen the threadable engagement. To allow the user to readily align the end portion  700  with the end base  704  to engage the threaded sections ( 706 ,  710 ), it is preferred for the end portion  700  to include a reduced guide section  712  that is configured to slidably and rotatably engage a base aperture reduced section  714 . 
     In this embodiment, the mechanical lock is provided by a combination of a spring-loaded pawl  716  which is positioned to engage a series of teeth  718  located on the end portion  700  of the shaft  702 . Each tooth  718  is configured to provide a ramp surface  720  which faces the direction of rotation when the shaft is being tightened. With the teeth  718  so configured, the spring loaded pawl  716  follows the ramp surfaces  720  when the shaft  702  is tightened, but blocks reverse turning of the shaft  702  by engaging blocking faces  722  that are provided on the teeth  718 . Thus, to reverse the direction of turning to loosen the shaft  702 , the pawl  716  must be retracted from engagement with the teeth  718 . Such can be readily done by a servo mechanism  724 . The servo mechanism  724  could be activated by a switch at a remote location, but more preferably is activated by a hand-held remote control such as a radio controller or a controller using bluetooth technology. For example,  FIG. 18  shows a bob  726  on a key ring that could be used to allow one to either block or allow rotation of the shaft  702 . Similar remote control technology could be employed in the embodiments discussed above which employ electrical discharge deterrents to deactivate these deterrent devices unless such are remotely activated by authorized personnel. 
       FIG. 19  is a schematic illustration of a bayonet connection to form a securable/releasable connection between a shaft  750  and a sidewall  752  of an end base  754 . The sidewall  752  is employed in combination with a base plate  756  which is biased by a spring  758 ; when the spring  758  is compressed, the combined sidewall  752  and base plate  756  provide a cavity  760  for housing an end portion  762  of the shaft  750 . The end portion  762  is provided with a pair of pins  764  (only one of which is visible in  FIG. 19 ) which extend from the end portion  762  and are sized such that they can each engage a “J”-shaped slot  766  in the sidewall  752 . Aligning the pins  764  with the slots  766  allows the end portion  762  to be partially slid into the cavity  760 . When the force is sufficient to overcome the bias of the spring  758 , the pin  764  can be moved along a long leg  768  to a bottom segment  770  of the slot  766 , and thereafter be turned to align with a short leg  772  of the slot  766 . At this point, upon release of the pressure, the pin  764  becomes seated in the end of the short leg  772  and thus the shaft  750  is not subject to turning when twisted. As with the threaded embodiment shown in  FIG. 18 , the turning of the shaft  750  in the base  754  could be blocked by a solenoid device to prevent removal of the shaft by unauthorized persons. The bayonet connection illustrated has an advantage over the threaded embodiment shown in  FIG. 18  in that it is more easily fabricated and requires less precise fit between the mating elements. 
       FIG. 20  illustrates an alternative bayonet-type coupling which does not require a shaft  800  to extend as far into an end base  802  as does the embodiment shown in  FIG. 19 . In this embodiment, the shaft  800  is biased by a compression spring in the other end base (not shown) and is provided with an angled slot  804 . The end base  802  has a pin  806  configured to engage the angled slot  804 . The angled slot  804  has a circumferential segment  808 , a first inclined segment  810 , and a second inclined segment  812 . When the shaft  800  is stored, the pin  806  is positioned at a closed end  814  of the circumferential segment  808 . To release the shaft  800 , the user rotates the shaft  800  to move the pin  806  to the junction between the circumferential segment  808  and the first inclined segment  810  (this rotation is counterclockwise as viewed looking toward the end base  802 ). At this point, the user must apply force to the shaft  800  while continuing to rotate it to overcome the bias of the compression spring and move the pin  806  along the first inclined segment  810  to the junction between the first inclined segment  810  and the second inclined segment  812 . To release the shaft  800 , the user must then rotate the shaft  800  in the other direction (clockwise as viewed looking toward the end base  802 ) while continuing to apply force against the bias spring to move the pin  806  along the second inclined segment  812  to exit the angled slot  804 . The requirement that the user apply force while rotating the shaft  800  subsequently in two different directions prevents accidental release of the shaft  800  when used for a supporting function while stored. 
       FIG. 21  is a perspective view of a section of an airplane cabin  850  which has installed therein a series of personal protection systems  852  of one embodiment of the present invention. In this embodiment, the personal protection systems  852  each have a shaft  854  which, in turn, is removably mounted in a first end base  856  and a second end base  858 . The bases ( 856 ,  858 ) mount to fixed surfaces  860  located in an upper section  862  of the airplane cabin  850 ; the shafts  854 , in combination with the bases ( 856 ,  858 ), form a natural extension of the cabin  850  and appear to be conventional air turbulence bars and become part of the background in which a flight attendant operates. However, each of the shafts  854  can be removed from the associated bases ( 856 ,  858 ) to provide a tool for use by the flight attendant to fend off an aggressor. 
       FIG. 22  is an isometric view showing a personal protection system  900  which forms an embodiment of the present invention which is configured to be installed in a shower stall  902 . The personal protection system  900  has a shaft  904  and a pair of bases  906 . The bases  906  mount to the shower stall  902  and supportably engage the shaft  904  so that it can serve as a safety bar. 
       FIG. 23  is an elevation view showing a personal protection system  950  which forms an embodiment of the present invention which is configured to be installed on a boat  952 . The personal protection system  950  has a shaft  954  and a pair of bases  956 , the bases  956  mounting to the boat  952  and supporting the shaft  954 . The shaft  954  is lockably and removably engaged with the bases so that the shaft  954  can serve the dual capacity of a grab rail and a deterrent device. For such applications, the bases  956  are configured to resemble conventional nautical fittings. It is preferred in such applications for the personal protection system  950  to employ only mechanical elements for providing a deterrent and for lockably engaging the shaft  954  to the end bases  956 , due to the susceptibility of electronic elements to corrosion when exposed to a marine environment. Furthermore, when a chemical irritant is employed, a gel is preferred since a gel is less susceptible to being misdirected by wind. 
     While the novel features of the present invention have been described in terms of particular embodiments and preferred applications, it should be appreciated by one skilled in the art that substitution of materials and modification of details obviously can be made without departing from the spirit of the invention.