Patent Publication Number: US-8534004-B2

Title: Rapid deployment and retraction telescoping mast system

Description:
A claim for domestic priority is made herein under 35 U.S.C. §119(e) to U.S. Provisional App. Ser. No. 61/388,192 filed on Sep. 30, 2010, the entire disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     The present exemplary embodiment relates to a rapid deployment and retraction telescoping mast system. It finds particular application in conjunction with telescoping masts relating to police, fire fighting, rescue, security, military, and communication industries, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications. 
     Telescoping mast systems can be operated in a variety of ways. It is common in the art to operate telescoping mast systems automatically by hydraulic or pneumatic actuation whereby a series of tubes are expanded to a desired height from a nested position by pressurized fluid or gas. In this instance, the mast is in communication with a compressor and/or a pressurized tank to provide pressurized fluid or gas to a series of cylindrical tubes. However, it is also known to operate the extension and retraction of a mast by mechanical means comprising a series of cables, ropes, winches or pulleys. 
     The body of the mast includes a series of tubes that typically comprise cylindrical shaped bodies, each having a generally hollow interior wherein each cylinder is interconnected with a passage for communication therethrough. Each tube generally has a flanged lip radially disposed away from a central axis at a bottom end and a flanged lip radially disposed toward the axis at a top end. The tubes concentrically engage one another wherein the exterior tube has a width greater than a first intermediate tube disposed therein. The first intermediate tube having a greater width than a second intermediate tube disposed therein and so on. This arrangement can comprise any number of tubes wherein the pinnacle of the mast includes a top tube having a width that is smaller than any other tube in the mast. The top tube is attached to the load intended to be deployed and/or retracted. 
     The plurality of tubes comprises a pressurized envelope that is typically achieved with a gasket or sleeve disposed between each tube. The sleeve can be made of an elostomeric or rubber type compound and maintains a seal between each tube while also allowing movement without pressure seepage. The tubes are deployed to a desired height and can be secured in place by maintaining the pressure within the mast. 
     Retraction of the mast is generally achieved by allowing gravitational forces to return the tubes and associate load to a nested position. This requires pressure to be vented from the envelope which is a function of the gravitational pull, the friction between the sleeves and tubes and the weight of the mast and load. The speed of this retraction is dependent on the payload weight and the surrounding environmental conditions. 
     Retractable poles and masts have been fabricated mostly from aluminum, with a few devices made of fiberglass. Such prior designs are typically bulky and may use complicated networks of pressurized air, cables, and pulleys to extend or collapse the poles, resulting in a time-consuming operation each time the apparatus is to be extended or retracted. 
     Pneumatic telescoping mast systems are typically retracted by opening an air release valve and allowing gravity to return the tubes and payload to the nested position. The speed of this retraction is dependent on the payload weight and the surrounding environmental conditions. 
     However, retraction of such a pole by its own weight necessitates the use of a pole with sufficient weight to accomplish such retraction in an efficient manner. Depending on the application, this variable retraction speed can pose risk to an associate operator and overall efficiency of the system. Therefore, it is desirable to have a rapid deployment and retraction mast to allow the operator the ability to quickly deploy and retract the mast in a consistent and repeatable fashion. There remains a need for a device and method for a controlled extendable and retractable telescoping mast which may be both quickly extended and retracted. 
     BRIEF DESCRIPTION 
     The present disclosure relates to a rapid deployment and retraction telescoping mast system. The disclosed system comprising a frame including a base for connection to an associate surface and a plurality of interconnected tube sections vertically disposed on the base. The tube sections including a base tube and a top tube and at least one intermediate tube there between. Each tube section comprising a generally hollow body wherein each tube is axially aligned with each of the plurality of tubes and defining a shared passage therethrough. The plurality of tube sections maintains an envelope having a pressurized seal arrangement. 
     One object of the disclosure provides a deployment mechanism including a compressor, storage tank, exhaust valve and isolation valve arranged about the frame and in communication with the plurality of interconnected tube sections. The compressor is in communication with the storage tank to generate pressurized air for storage in the tank. The storage tank is in communication with the plurality of tubes in series arrangement with the isolation valve wherein the tank becomes isolated from the plurality of tubes during non-operation while the isolation valve is closed. Compressed air is introduced into the plurality of tubes when the isolation valve is in the open position wherein increasing the pneumatic pressure within the sealed envelope of the plurality of tubes. The increase of pressure generated by the deployment mechanism provides a deployment force within the plurality of interconnected tubes causing controlled deployment of the telescoping mast. 
     An additional object of the disclosure provides a retraction mechanism including a resilient member, a retraction reel, a reel shaft, and a motor disposed about the frame. The retraction reel and at least a portion of the reel shaft are disposed within a sealed housing. The resilient member extends from the retraction reel and is rigidly attached to the top tube of the plurality of tube sections through a resilient passage. The resilient passage is sealed and in communication with the hollow sealed passage defined by the plurality of interconnected tubes. The retraction reel includes an arcuate edge radially extending from a central axis. The resilient member rotably engages the retraction reel at the arcuate edge and the reel shaft axially engages the retraction wheel at the central axis. The reel shaft adapts to a motor to introduce mechanical force to the retraction mechanism whereby upon operation of the motor, the reel shaft rotates the retraction reel and winds the resilient member creating a retraction force on the top tube causing controlled retraction of the telescoping mast. At the time the retraction mechanism is operated, the exhaust valve, in communication with the plurality of tubes, is opened to allow for the reduction of pressure. The exhaust valve and motor can be toggled for optimal control over the retraction speed of the mast. 
     In one embodiment, the plurality of telescoping tubes include sliding and sealing surfaces between the tubes, a first plug member on the upper end of the smallest cylinder, and a second plug member on the lower end of the largest cylinder, wherein pressurize air admitted to the base tube and cause the deployment of the tubes to slide relative to one another causing the mast to extend. An elastomeric sleeve connects a tube with one of the intermediate tubes to seal one tube to another when the mast is fully extended. The elastomeric sleeve further serves to provide a cushion to prevent damage to the cylinders when the pole is urged back into a nest position by the retraction mechanism and the venting of the pressure. 
     Yet another embodiment provides a controller box in electrical communication with the compressor, isolation valve, exhaust valve, storage tank, motor and associate sensing and controlling elements. A potentiometer device is provided about the reel shaft to communicate reel shaft frequency data to the controller box. The controller box may be used to record and store data as well as manipulate known toggleable functions of the associate elements within the system. 
     In yet another embodiment, a torsion spring is provided in the housing to provide a supporting force to the retracting reel therein reducing undesired slack of the resilient member. 
     A further embodiment provides a clutch bearing operably coupled between the reel shaft and the motor to allow free rotation of the reel shaft and retraction reel in the direction of motor rotation when not engaged. The clutch bearing also allows the transfer of torque from the motor to the reel shaft in the retraction direction when engaged. 
     An advantage of the present disclosure is a device that rapidly deploys and retracts a plurality of interconnected tubes with a controllable and consistent rate 
     In a further advantage of the present disclosure is to provide the repeatable retraction time required for a telescoping mast under all environmental conditions and mast orientations. Particularly, consistency problems for mast operation within cold temperatures and at angled grades are overcome by this disclosure. 
     It is also an advantage of the present disclosure to provide a telescoping mast system having a design architecture with a lower cost than other mast devices. 
     Still other features and benefits of the present disclosure will become apparent from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the rapid deployment and retraction telescoping mast system; 
         FIG. 2  is cross sectional schematic view of the retraction mechanism; 
         FIG. 3  is a sectional view of the plurality of interconnecting tubes and a schematic view of the deployment mechanism and the retraction mechanism of the telescoping mast system; 
     
    
    
     DETAILED DESCRIPTION 
     It is to be understood that the detailed figures are for purposes of illustrating exemplary embodiments only and are not intended to be limiting. Additionally, it will be appreciated that the drawings are not to scale and that portions of certain elements may be exaggerated for the purpose of clarity and ease of illustration. 
     In accordance with the present disclosure a system and method are provided which automatically control the deployment and retraction of a telescoping mast system. The system can be used to provide hoisting for all types of applications including but not limited to personnel lifts, communication towers, antennas, satellites, material hoists, platforms, and any other application that requires displacement from the base to a predetermined height. 
     The mast system combines the positive aspects of a pneumatic mast system and mechanical retraction mechanism for the purpose of rapid deployment and retraction of a telescoping mast system. The system combines the low cost benefits of a pneumatic mast with the controlled motion and positive retraction force of a mechanical mast. Disclosed is a pneumatic mast equipped with a mechanical retraction system. This system consists of a powered reel and automated pneumatic exhaust valve. To maintain the pneumatic sealing integrity of the mast, the powered reel mechanism is integrated within a pressure vessel. 
     With reference to  FIG. 1  &amp;  FIG. 3 , a telescoping mast system  100  controls the rapid deployment and retraction of an associate load  105 . The telescoping mast system  100  includes a frame  110  for securing different elements of the system. The frame  110  includes a base  120  for adapting the telescoping mast system to an associate surface. The base  120  includes a plurality of anchors  130  for a stable connection to the surface. The anchors  130  should be rigidly connected to ensure a safe, consistent operation of the telescoping mast system  100 . It is to be understood that an unsuitable base  120  connection would increase the risk of improper operation whereby the system  100  would be subject to tipping, shaking or falling. 
     A plurality of interconnected tube sections  140  are vertically joined to the base  120 . The tube sections  140  include a base tube  150  and a top tube  160  with intermediate tubes  170  there between. Each tube section  140  comprises a generally hollow body  180  wherein the base tube  150  is axially aligned to the intermediate tubes  170  and the top tube  160 . The plurality of tubes  140  define a hollow shared passage  460  from the combination of hollow bodies. The plurality of tubes  140  maintain an envelope having a pressurized seal arrangement. 
     The plurality of tubes  140  may include a plurality of sliding and sealing surfaces  190  between the tubes  140 . The sealing surfaces  190  comprise an elastomeric sleeve  190  that connects at least the base tube  150  with one of the intermediate tubes  170  to seal one tube to another when the mast system  100  is fully extended. The elastomeric sleeve also provides a cushion to prevent damage to the cylinders when the pole is urged back into a nest position  200  as shown. The base tube  150  has a closed first end  205  opposing a second end  210  that interconnects intermediate tubes  170 . The top tube  160  has a closed first end  220  opposing a second end  230  away from the base  120 , thereby creating a sealed envelope within the hollow bodies of the plurality of tubes  140 . The sealed envelope allows pressurized air to enter the base tube  150  without pressure leakage and helps deploy the tubes  140  relative to one another causing the mast to extend vertically. 
     A deployment mechanism  300  is provided about the frame  110  of the telescoping mast system to automatically control the deployment function of the system. The deployment mechanism  300  includes a compressor  310 , at least one storage tank  320 , an exhaust valve  330  and an isolation valve  340 . In the preferred embodiment of  FIG. 1 , the compressor  310  is located on the base  120  of the frame  110  and maintains pressurized communication with the storage tank  320  while the storage tank  320  is structurally adapted to the base tube  150 . The exhaust valve  330  and isolation valve  340  are also provided about the frame  110 . It is noted that this organizational structure is not limited to this arrangement as any other structural locations for the different elements is also covered by this disclosure. 
     The isolation valve  340  is aligned in a passage that remains in communication between the storage tank  320  and the base tube  150 . The isolation valve  340  may comprise any type of plumbing, hydraulic or pneumatic type shut off valve known in the prior art whereas an electrical solenoid valve is preferable. The passage may comprise any durable plumbing material suitable to allow the transfer of pneumatic pressure in a controlled manner while preventing unnecessary pressure loss due to leaks. Utilizing stored energy in the form of compressed air allows rapid deployment that is not dependent on the flow rate of the compressor. The width of the passage as it exists between the isolation valve  340  and the base tube  150  can be adjusted to increase or decrease the speed of the telescoping mast deployment. Deployment speed can also be tunable by adjusting the tank pressure or volume. 
     When engaged into operation, the compressor  310  generates pressurized air provided to the storage tank  320 . Tank pressure is controlled by a pressure switch. The storage tank  320  remains in communication with the plurality of tubes  140  and in series alignment with the isolation valve  340  and the base tube  150 . The isolation valve  340  may be automatically toggled by one or more signals provided by a control box  500 , which is in electrical communication with the isolation valve  340 . The isolation valve  340  range between opened and closed can be modulated to provide more precise control over the pressurized air provided from the storage tank  320  to the base tube  150 . Compressed air is introduced into the plurality of tubes  140  when the isolation valve  340  is in the open position thereby increasing the pneumatic pressure within the sealed envelope of the plurality of tubes  140 . The increase of pressure generated by the deployment mechanism provides a deployment force within the plurality of interconnected tubes. The deployment force acts on the plurality of tubes  140  to urge each tube into an extended position  350 . The isolation valve  340  remains closed during the non-operation of the system or otherwise while the system is at rest. The plurality of tubes may remain at rest while in the nest position  200  or at rest in the extended position  350 . 
     The retraction mechanism  400  is depicted in  FIGS. 1 and 2  but will be described in particularity as identified in  FIG. 2 . The retraction mechanism  400  includes a resilient member  410 , a retraction reel  420 , a reel shaft  430 , and a motor  490  disposed about the base  120  of the frame  110 . The retraction reel  420  and at least a portion of the reel shaft  430  are disposed within a pneumatically sealed housing  440 . The sealed housing  440  maintains a pressurized volume by utilizing static O-ring seals  445  on the housing cover and rotating shaft U-cup seals  455  on the reel shaft  430 . The O-ring seals  445  are provided about a sealing wall  446  of a housing cover  560  and are provided in sealing engagement with the sealed housing  440  to help prevent pressure leaks. The U-cup seals  455  are provided about a sealing wall  456  of the housing cover  560  at a location surrounding the shaft reel  430 . The U-Cup seals  455  dynamically and seallingly engage the reel shaft  430  to help prevent pressure leaks from the sealed housing  440  while the reel shaft  430  is rotated. At least a portion of the reel shaft  430  is located within the sealed housing  440  and engages axial sleeve bearings  435 ,  436  for consistent dynamic rotational motion between the reel shaft  430 , the sealed housing  440  and the housing cover  560 . 
     The motor  490  is supported and attached to a mounting bracket  520  by mechanical fasteners  590 . The housing cover  560  is sealingly attached to the sealed housing  440  by mechanical fasteners  600 . The resilient member  410  may comprise any material known in the art to that provides a connection between multiple elements allowing a pulling force sufficient to overcome a predetermined weight of a load to be deployed and retracted. Capable resilient members  410  may include but not be limited to bungee cords, rope, chain, cable, straps, nylon, rubber, etc. 
     In a preferred embodiment that can be better understood by  FIG. 3 , the resilient member  410  extends from the retraction reel  420  and is rigidly attached to the top tube  160  of the plurality of tube sections through an internal resilient passage  450 . The resilient passage  450  is sealed and defines a pressurized communication pathway between the hollow sealed passage  460  defined by the plurality of interconnected tubes  140  and the sealed housing  440 . As can be appreciated in  FIG. 2 , the retraction reel  420  includes an arcuate edge  470  radially extending from a central axis  480 . The resilient member  410  rotably engages the retraction reel  420  at the arcuate edge  470  and the reel shaft  430  engages the retraction reel  420  in axial alignment with the central axis  480 . 
     The reel shaft  430  adapts to the motor  490  to introduce a rotational mechanical force to the retraction mechanism  400 . Upon operation of the motor  490 , the reel shaft  430  rotates the retraction reel  420  thereby winding the resilient member  410  about the retraction reel  420  and creating a retraction force on the top tube  160 . The top tube  160  acts on all tube sections to mechanically retract the mast. A clutch bearing  570  is provided about a clutch housing  580  within the mounting bracket  520 . The clutch housing  580  is axially aligned to the reel shaft  430  and motor  490  to allow the clutch bearing  570  to operatively engage the reel shaft  430  and to transfer the torque from the motor  490  to the reel shaft  430 . The reel shaft  430  is coupled to the clutch housing with a key and set screw arrangement. The clutch bearing  570  engages the reel shaft  430  to transfer torque provided by the motor  490  and allows the reel shaft  430  to freely rotate (freewheel) in the same rotational direction as the winding of the resilient member  410 . The clutch bearing  570  (also known as a one way bearing) is set in the clutch housing  580  with a press fit and is coupled to the motor using a key. 
     A torsion spring  540  is provided in the sealed housing  440  to provide a supporting force to the retraction reel  420 . This supporting force helps to reduce extra slack of the resilient member  410  that may exist in mechanical winch type systems such as this. The torsion spring  540  is a multi-turn, mechanical spring which includes a dynamic end that attaches to the retraction reel  420  with a tab and slot arrangement  550 . The opposing end of the torsion spring  540  is statically attached to a housing cover  560  with a screw  575 . The torsion spring  540  acts on the retraction reel  420  in a direction that keeps the resilient member  410  in tension and generally removes the risk of slack development in the resilient member  410 . The direction of this force is the same direction as the rotational force provided by the motor  490  and the free-wheeling direction due to the clutch bearing  570  and reel shaft  430  arrangement. The torsion spring  540  is also supported by a spring retainer  585  located within the sealed housing  440 . The clutch bearing  570  allows the torsion spring torque to act without needing to energize the motor in the opposite direction. The clutch bearing  570  allows the torsion spring  540  to retract the resilient member  410  even if the rotation speed needed exceeds the retraction motor rotation speed. This might occur if gravity causes the mast to retract faster than the retraction motor speed dictates. 
     However, during deployment, the resilient member  410  is unwound from the retraction reel  420 . The clutch bearing  570  applies torque in the direction that causes the motor  490  to be back-driven. The dynamic end of the torsion spring  540  rotates which increases the torque to a maximum value when the plurality of tubes  140  are fully extended. 
     At the time the retraction mechanism  400  is operated, the exhaust valve  330 , in communication with the hollow passage  460  through the base tube  150 , is opened to allow for the reduction of pressure influencing the downward motion of the tubes  140 . The exhaust valve  330  orifice size, along with the power and speeds of the motor  490 , can be toggled along with a designed diameter of the retraction reel  470  for optimal control over the retraction speed of the mast system. Additionally, the deployment and retraction speeds are a function of the dual operation of both the deployment mechanism  300  and the retraction mechanism  400 . Adjustment or modulation of an element of the deployment mechanism  300  may have an effect on the speed of mast retraction and likewise adjustment or modulation of an element in the retraction mechanism  400  may have an effect on the speed of mast deployment. 
     The controller box  500  may be in electrical communication with the compressor  310 , isolation valve  340 , exhaust valve  330 , storage tank  320 , motor  490  and associate sensing and controlling elements. A potentiometer device  510  is provided within the mounting bracket  520  of the retraction mechanism to communicate with the reel shaft  430  by way of a pulley belt  530 . Potentiometer devices are well known in the art to provide electronic computational signals in addition to other controlling features. The potentiometer  510  provides a signal to the controller box  500  indicating the rate and quantity of revolutions of the reel shaft  430  for optimal control and monitoring of the rotational speed of the retraction reel  420  and the telescoping mast system. 
       FIG. 3  provides a clear schematic depiction of the operational elements of the present disclosure and a partial cross sectional view of the plurality of tubes  140 . The resilient member  410  extends from the retraction mechanism  400  and rotationally engages a pulley member  610 . The pulley member rotationally directs the resilient member  410  towards a central axis of the plurality of tubes  140  in a generally perpendicular direction from the axis where the resilient member  410  extends from the retraction mechanism  400 . The resilient member  410  rigidly connects to the top tube  160  at the second side  230 . However, the resilient member  410  may also connect to the top tube  160  at the first side  220 . 
     The telescoping mast system  100  rapidly deploys and retracts a plurality of interconnected tubes  140  with a controllable and consistent rate required for a telescoping mast under all environmental conditions and mast orientations. Particularly, consistency problems for mast operation within cold temperatures and at angled grades are overcome by this disclosure. These features are functional due to the pressurized envelope of the system as it is maintained with countervailing mechanical forces in a predetermined and programmable way thereby optimizing deployment and retraction speeds of the telescoping mast. This concept is scalable to different mast heights and diameters. 
     This disclosure particularly overcomes environmental conditions such as cold temperatures with frost build-up on the tubes and operating the mast at grades greater than horizontal as they cause difficulty with a purely pneumatic mast in regards to retraction time. 
     Other concepts to provide the rapid retraction function are as follows: Draw vacuum in the mast pressure chamber to allow atmospheric pressure on the outside of the tubes to provide a downward pressure differential force to retract the mast. 
     The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.