Abstract:
An elevator evacuation apparatus is described, which enables a person(s) trapped in a stopped elevator car to pull a emergency cable outside a car window to activate a cam based pulley and gear mechanism which in turn intermittently releases and actuates a brake, thereby slowly lowering the stopped car until arriving at a correct floor. A number of embodiments are possible.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The invention relates to apparatus for enabling person(s) trapped in a stopped elevator car to evacuate safely, and more particularly to such an elevator evacuation apparatus with improved characteristics. 
   2. Description of Related Art 
   Components of a first conventional elevator evacuation arrangement mounted in a machine room (not shown) are shown in  FIG. 1  and comprise a motor  1 , a drive sheave  2  driven by the motor  1 , a plurality of parallel ropes  3  run through rope grooves of the drive sheave  2 , the ropes  3  having one ends connected to a top of an elevator car (not shown) and the other ends connected to a counterweight (not shown), and a brake  4  mechanically connected to the motor  1 . The brake  4  is adapted to actuate to stop the rotation of the drive sheave  2  in case of emergency (e.g., power outage). 
   Components of the first conventional elevator evacuation arrangement further comprise a lever  5  having a shaft  5   a , and a cam  6 . Typically, a skilled mechanic is called to enter the machine room to manually push the lever  5  to actuate the cam  6  via the shaft  5   a . The cam  6  in turn presses down a member (e.g., plunger) to release the brake  4 . Thereafter, the drive sheave  2  is able to rotate again for lowering the car to a next floor since it is typical that the car did not stop at the correct floor location when the emergency occurred. Eventually, person(s) trapped in the car can evacuate safely. 
   The first conventional elevator evacuation arrangement has the following disadvantages. For example, it requires calling a skilled mechanic to come to the site for troubleshooting. This inevitably will delay the precious saving time and it is highly undesirable. Moreover, a successful evacuation depends on the unbalanced state (i.e., weight of the counterweight being not equal to that of the stopped car so that the car is capable of lowering in response to releasing the brake  4 ). Hence, the skilled mechanic is useless if the car is in a balanced state. 
   A second conventional elevator evacuation arrangement is shown in  FIG. 2  in which a rod  7   a  is extended out of a member (e.g., plunger) of a brake  7  and a spring  7   b  is put on shank of the rod  7   a . A skilled mechanic has to press the spring depressible rod  7   a  to release the brake  7  via the plunger in the troubleshooting procedure. The second conventional elevator evacuation arrangement also has the disadvantage of requiring a skilled mechanic to come to the site for troubleshooting. 
   A third conventional elevator evacuation arrangement is shown in  FIG. 3  in which a disc brake is provided between a drive sheave  2  and a motor  1 , and the brake comprises brake pads  8   a  and a disc  8 . In operation, a skilled mechanic may manually push a lever  8   b  to actuate the brake pads  8   a . The brake pads  8   a  in turn urge against the disc  8  to release the brake. The third conventional elevator evacuation arrangement still has the disadvantage of requiring a skilled mechanic to come to the site for troubleshooting. 
   There have been numerous suggestions in prior patents for enabling person(s) trapped in a stopped elevator car to evacuate safely. For example, U.S. Pat. No. 6,739,431 discloses an elevator escape device. Thus, continuing improvements in the exploitation of elevator evacuation apparatus are constantly being sought. 
   SUMMARY OF THE INVENTION 
   It is therefore one object of the invention to provide an apparatus for enabling 
   person(s) trapped in a stopped elevator car to pull an emergency cable outside a car window to activate a cam based pulley and gear mechanism which in turn intermittently releases and actuates a brake, thereby slowly lowering a stopped car until arriving a correct floor. 
   The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic side view of a first conventional elevator evacuation arrangement; 
       FIG. 2  is a schematic side view of a second conventional elevator evacuation arrangement; 
       FIG. 3  is a schematic side view of a third conventional elevator evacuation arrangement; 
       FIG. 4  is a schematic side view of a first preferred embodiment of elevator evacuation apparatus according to the invention; 
       FIG. 5  is a sectional view taken along line A-A of  FIG. 4  where a first configuration of the first cam according to the invention is shown in its inoperative position; 
       FIG. 6  is a view similar to  FIG. 5  where the first cam is operating; 
       FIG. 7  is a schematic sectional view of a first configuration of the second cam according to the invention; 
       FIG. 8  is a schematic sectional view of a first configuration of the first cam according to the invention; 
       FIG. 9  is a schematic sectional view of a second configuration of the first cam according to the invention; 
       FIG. 10  is a schematic sectional view of a second configuration of the second cam according to the invention; 
       FIG. 11  is a schematic sectional view of a third configuration of the second cam according to the invention; 
       FIG. 12  is a schematic side view of a second preferred embodiment of elevator evacuation apparatus according to the invention; 
       FIG. 13  is a sectional view taken along line B-B of  FIG. 12  where the rod according to the invention is shown in its inoperative position; 
       FIG. 14  is a view similar to  FIG. 13  where the rod is operating; 
       FIG. 15  is a schematic side view of a third preferred embodiment of elevator evacuation apparatus according to the invention; 
       FIG. 16  is a sectional view taken along line C-C of  FIG. 15  where the lever according to the invention is shown in its inoperative position; and 
       FIG. 17  is a view similar to  FIG. 16  where the lever is operating. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 4 to 11  an elevator evacuation apparatus in accordance with a first preferred embodiment of the invention is shown. The apparatus is mounted in a machine room (not shown) and comprises a motor  11 , a drive sheave  13  driven by the motor  11 , a brake  12  mechanically connected to the motor  11  and provided between the drive sheave  13  and the motor  11 . The evacuation apparatus includes an intermittent brake release mechanism and an auxilliary drive for urging the drive sheave in an emergency when the brake is released. 
   The brake  12  comprises a brake operating device, which in one embodiment has two opposite plungers  121  and a brake shoe  122  connected to both the plungers  121 . The intermittent brake release mechanism has a first shaft  20  that is provided externally of the motor  11  and comprises a first cam  21  formed therearound. The first cam  21  is provided between the plungers  121  and spaced therefrom in its inoperative position (see  FIG. 5 ). A proximal first gear  30  and a distal emergency pulley  40  are coaxially provided on the first shaft  20 . The auxilliaiy drive has a second gear  31  that is in mesh with the first gear  30 . A second cam  33  is spaced from the second gear  31  and a second shaft  32  passes both the second cam  33  and the second gear  31  so that the second cam  33  and the second gear  31  can rotate coaxially with respect to the second shaft  32 . The second cam  33  in turn is adapted to intermittently engage with the rim of the drive sheave  13  as detailed later. An emergency cable  14  runs through the grooved rim of the emergency pulley  40  to pass down and dispose externally of a window  101  of a car  10 . 
   In response to a stop of the elevator in case of emergency (e.g., due to power outage), the brake shoe  122  actuates to stop the rotation of the drive sheave  13 . Also, the car  10  does not stop at the correct floor location. Hence, a person trapped in the car  10  has to reach his or her hand out of the window  101  to hold and pull down the emergency cable  14 . As a result, the emergency pulley  40  turns and thus both the first shaft  20  and the first gear  30  turn. At the same time, the first cam  21  turns to alternatingly release the brake  5  shoe  122 , by pushing the plungers  121  further away from each other at one time, and to actuate the brake shoe  122  by disengaging from the plungers  121  with the plungers  121  returning to their inoperative positions at a subsequent time. That is, the brake shoe  122  releases and actuates intermittently. Also, the second gear  31  turns in a direction opposing that of the first gear  30  and the second cam  33  turns the same direction as the second gear  31 . As a result, the second cam  33  intermittently turns the drive sheave  13 . Therefore, the car  10 , conneded to one ends of hoist ropes (not numbered), lowers on the hoist ropes run through rope grooves of the drive sheave  13  and by a passenger pulling down on the emergency cable  14  causing a rotation of the drive sheave  13  aided by the difference in weight of a counterweight (not numbered) if unequal to that of the stopped car  10  (i.e., as when the car  10  is in its unbalanced state). The trapped person can stop the pulling when the car  10  has arrived at the correct floor. Eventually, person(s) trapped in the car  10  can evacuate safely. 
   As shown in  FIG. 5 , the first cam  21  has a section of oval. Distance between ends of the plungers  121  is a minimum when short axis of the first cam  21  is aligned with the plungers  121  and the first cam  21  does not contact the plungers  121 . At this position, the brake shoe  122  is actuated. 
   As shown in  FIG. 6 , the first cam  21  turns clockwise as indicated by arrow in response to turning the first shaft  20 . Distance between the ends of the plungers  121  is a maximum when long axis of the first cam  21  is aligned with the plungers  121  and the first cam  21  contacts the plungers  121  by pushing them further away from each other (see arrows). At this position, the brake shoe  122  is released. Moreover, the weight of the counterweight is not unequal to that of the stopped car  10  (i.e., the car  10  is in its unbalanced state). As a result, the drive sheave  13  turns to lower the car  10 . 
   As shown in  FIG. 7 , a first configuration of the second cam  33  has a raised member  331  on either end of its long axis. The raised members  331  are adapted to contact the rim of the drive sheave  13  or not during the car lowering operation. 
   As shown in  FIG. 10 , a second configuration of the second cam  33  has a section of square and four raised members  331  on four corners. 
   As shown in  FIG. 11 , a third configuration of the second cam  33  has a section of hexagon and six raised members  331  on six angles. 
   Preferably, the raised members  331  are pads. 
   As shown in  FIG. 8 , a first configuration of the first cam  21  has a section of square. As shown in  FIG. 9 , a second configuration of the first cam  21  has a section of hexagon. 
   Referring to  FIGS. 12 to 14  an elevator evacuation apparatus in accordance with a second preferred embodiment of the invention is shown. The characteristics of the second preferred embodiment are detailed below. An idler gear  35  turning on its shaft  34  is provided between the second gear  31  and the first gear  30  and is in mesh with the both. The first cam  21  has a section of square and is adapted to turn on the first shaft  20 . A rod  50  is extended out of the brake shoe  122  and a spring  51  is put on shank of the rod  50 . The rod  50  is in close proximity to one side of the first cam  21  but does not contact it. That is, the brake shoe  122  is released in a normal operation of the elevator. The brake shoe  122  actuates to stop the rotation of the drive sheave  13  in case of emergency (e.g., due to power outage). Also, the car  10  does not stop at the correct floor location. Hence, a person trapped in the car  10  can reach his or her hand out of the window  101  to hold and pull down the emergency cable  14 . As a result, the emergency pulley  40  turns and thus both the first shaft  20  and the first gear  30  turn. At the same time, the first cam  21  turns to release the brake shoe  122  by pressing the rod  50  in one time and actuate the brake shoe  122  by disengaging with the rod  50  in an immediately next time. That is, the brake shoe  122  releases and actuates intermittently. Also, the second gear  31  turns in a direction the same as that of the first gear  30  via the meshed idler gear  35 . Also, the second cam  33  turns the same direction as the second gear  31 . As a result, the second cam  33  intermittently turns the drive sheave  13 . Therefore, the car  10 , connected to one ends of the hoist ropes, lowers by pulling down the hoist ropes run through the rope grooves of the drive sheave  13  and by causing weight of the counterweight to be unequal to that of the stopped car  10  (i.e., the car  10  is in its, unbalanced state). The trapped person can stop the pulling when the car  10  has arrived the correct floor. Eventually, person(s) trapped in the car  10  can evacuate safely. 
   Referring to  FIGS. 15 to 17  an elevator evacuation apparatus in accordance with a third preferred embodiment of the invention is shown. The characteristics of the third preferred embodiment are detailed below. A disc brake comprises a disc  60  between the drive sheave  13  and the motor  11 , brake pads  61  at one ends of the disc  60 , and a lever  62  operatively connected to the brake pads  61  and spaced from the first cam  21  by a gap. The brake pads  61  actuate to stop the rotation of the drive sheave  13  in case of emergency (e.g., due to power outage). Also, the car  10  does not stop at the correct floor location. Hence, a person trapped in the car  10  can reach his or her hand out of the window  101  to hold and pull down the emergency cable  14 . As a result, the emergency pulley  40  turns and thus both the first shaft  20  and the first gear  30  turn. At the same time, the first cam  21  turns to release the brake pads  61  by pivoting the lever  62  counterclockwise (see arrow of FIG  17 ) in one time and actuate the brake pads  61  by disengaging with the lever  62  in an immediately next time. That is, the brake pads  61  release and actuate intermittently. Also, the second gear  31  turns in a direction opposite that of the first gear  30  and the second cam  33  turns the same direction as the second gear  31 . As a result, the second cam  33  intermittently turns the drive sheave  13 . Therefore, the car  10 , connected to one ends of the hoist ropes, lowers by pulling down the hoist ropes run thrbugh rope grooves of the drive sheave  13  and by causing weight of the counterweight to be unequal to that of the stopped car  10  (i.e., the car  10  is in its unbalanced state). The trapped person can stop the pulling when the car  10  has arrived the correct floor. Eventually, person(s) trapped in the car  10  can evacuate safely. 
   While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.