Patent Publication Number: US-7914057-B2

Title: Vacuum anchor

Description:
FIELD OF THE INVENTION 
     The present invention relates to a vacuum anchor to be used as an anchorage connector for connection of a personal fall protection system for personnel working on aircraft or other anchorage structures. 
     BACKGROUND OF THE INVENTION 
     Safety devices enabling personnel to perform maintenance or inspection procedures on large anchorage structures such as aircraft, storage tanks, ships, submarines, railcars, trucks, roofs, and other anchorage structures are commonly used. One type of safety device commonly used on such anchorage structures is a vacuum anchor because the vacuum anchor does not damage the surface of the anchorage structure to which it is operatively connected by suction, provided the anchorage structure meets safety standards. A remote vacuum source is typically used to supply a vacuum to the vacuum anchor and to create the suction thereby operatively connecting the vacuum anchor to the anchorage structure. The vacuum anchor depends upon the vacuum being supplied by the remote vacuum source. Should the hose interconnecting the vacuum source and the vacuum anchor become obstructed such as by being pinched, clogged, or disconnected, the vacuum supplied to the vacuum anchor will be adversely affected thereby affecting the suction of the vacuum anchor. Should the vacuum become insufficient to secure the vacuum anchor, an alarm indicating the insufficient vacuum level will not provide sufficient notice to the user thereby potentially creating a risk of a fall hazard while the user connects to a safe anchorage point. The hose interconnecting the vacuum source and the vacuum anchor may create a trip hazard, and it may be time consuming to install. It is desired to create a vacuum anchor that is easy to install and provides a reliable anchorage point. 
     SUMMARY OF THE INVENTION 
     In one aspect of the invention, a vacuum anchor assembly for anchoring a fall protection system to a surface of an anchorage structure comprises an anchor member having an air input connector, a venturi, and a seal member incorporated into the anchor member. The air input connector is configured and arranged to receive air from a pressurized air source. The venturi is in fluid communication with the air input connector and is configured and arranged to receive air and create a vacuum therefrom. The seal member is in fluid communication with the venturi and is configured and arranged to receive the vacuum and resulting suction and create a seal between the anchor member and the surface of the anchorage structure sufficient to operatively connect the anchor member to the surface of the anchorage structure with the vacuum and resulting suction created within the anchor member. 
     In another aspect of the invention, a self-contained vacuum anchor assembly for anchoring a fall protection system to a surface of an anchorage structure comprises an anchor member having a housing, an air input connector, a venturi, and a seal member incorporated into the anchor member. The housing contains the venturi. The air input connector is configured and arranged to receive air from a pressurized air source. The venturi is in fluid communication with the air input connector and is configured and arranged to receive air and create a vacuum therefrom. The seal member is in fluid communication with the venturi and is configured and arranged to receive the vacuum and resulting suction and create a seal between the anchor member and the surface of the anchorage structure sufficient to operatively connect the anchor member to the surface of the anchorage structure with the vacuum and resulting suction created within the anchor member. 
     In another aspect of the invention, a method of securing a vacuum anchor assembly to a surface of an anchorage structure for anchoring a fall protection system to the surface comprises placing the vacuum anchor assembly on the surface of the anchorage structure, connecting the vacuum anchor assembly to a pressurized air source, creating a vacuum internally within the vacuum anchor assembly from the pressurized air source, and securing the vacuum anchor assembly to the surface of the anchorage structure with suction resulting from the vacuum. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view of a vacuum anchor constructed according to the principles of the present invention; 
         FIG. 2  is a top plan view of the vacuum anchor shown in  FIG. 1  with a guard plate removed; 
         FIG. 3  is a top plan view of the vacuum anchor shown in  FIG. 2  with an air compressor bottle and fittings removed; 
         FIG. 4  is a top plan view of the vacuum anchor shown in  FIG. 3  with a housing plate removed; 
         FIG. 5  is bottom plan view of the vacuum anchor shown in  FIG. 4 ; 
         FIG. 6  is a schematic diagram of a pneumatic system of the vacuum anchor shown in  FIG. 1 ; 
         FIG. 7  is a schematic diagram of an electrical system of the vacuum anchor shown in  FIG. 1 ; 
         FIG. 8  is a top plan view of an auxiliary vacuum anchor constructed according to the principles of the present invention; 
         FIG. 9  shows an energy absorbing lanyard interconnecting a harness donned by a user and the vacuum anchor shown in  FIG. 1 ; 
         FIG. 10  shows one end of a horizontal lifeline operatively connected to the vacuum anchor shown in  FIG. 1  and the other end of the horizontal lifeline operatively connected to the auxiliary vacuum anchor shown in  FIG. 8  and an energy absorbing lanyard interconnecting a harness donned by a user and the horizontal lifeline; 
         FIG. 11  is an exploded side view of an anchor member of the vacuum anchor shown in  FIG. 1 ; 
         FIG. 12  is a bottom view of the anchor member shown in  FIG. 11 ; 
         FIG. 13  is a cross section view taken along the lines  13 - 13  in  FIG. 12 ; 
         FIG. 14  is a cross section view taken along the lines  14 - 14  in  FIG. 12 ; 
         FIG. 15  is a side view of the anchor member shown in  FIG. 1 ; and 
         FIG. 16  is a schematic diagram of a pneumatic system of the auxiliary vacuum anchor shown in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     A preferred embodiment vacuum anchor constructed according to the principles of the present invention is designated by the numerals  100  and  100 ′ in the drawings. A preferred embodiment auxiliary vacuum anchor constructed according to the principles of the present invention is designated by the numeral  160  in the drawings. 
     The vacuum anchor  100  includes a first anchor member  101  and a second anchor member  108 . The first anchor member  101  preferably includes a first seal member  103  sandwiched between a first plate member  102  and a first bottom plate member  106  and operatively connected therebetween by fasteners  116  as shown in  FIG. 11 . The fasteners  116  extend through the first plate member  102 , the first seal member  103 , and the first bottom plate member  106  and are secured thereto. Preferably, the fasteners  116  are bolts and nuts but other suitable fasteners could be used. The first plate member  102  and the first bottom plate member  106  are each preferably rectangular plates made of aluminum, although it is recognized that other suitable materials such as steel and carbon fiber composite material could also be used. The first seal member  103  is preferably a flexible concave member made of ethylene propylene because of its compatibility with SKYDROL™, a hydraulic fluid commonly used in aircrafts, as ethylene propylene has an acceptable resistance to deterioration when contacted with SKYDROL™. However, it is recognized that other suitable materials such as polychloroprene, nitrile, silicone, and natural rubber could also be used for the first seal member  103  depending upon the application and the environment of use. 
     The first seal member  103  includes sealing lips  103   a  and  105  proximate a bottom surface of the first seal member  103 . The bottom surface of the first seal member  103  is shown in  FIG. 5 . The sealing lip  103   a  is proximate the bottom perimeter of the first seal member  103  and forms the main seal between the first anchor member  101  and the surface of the anchorage structure to which it is attached. The sealing lips  105  are preferably concentric rings proximate the sealing lip  103   a  and provide backup seals in the event the main seal of sealing lip  103   a  is breached. Preferably, there are three rings of sealing lips  105  on the first seal member  103 , and the distance between the sealing lips  105  is preferably approximately 0.188 inch, but the distance could vary depending upon the size of the first seal member  103 . 
     As shown in  FIG. 1 , the first plate member  102  includes a connector  152  and a fitting  152   a . The fitting  152   a  connects the connector  152  to the first plate member  102 , and the connector  152  is configured and arranged to connect to a first vacuum inlet hose  126 . As shown in  FIGS. 12-14 , the first bottom plate member  106  includes apertures through which portions of the first seal member  103  extend as scuff pads  154  to cushion and protect the surface of the anchorage structure so that it does not get scratched or damaged by the first bottom plate  106 . Preferably, there are three scuff pads  154  aligned along the longitudinal axis of the first bottom plate member  106 , and there is a relatively larger scuff pad  154  located proximate the middle of the first bottom plate member  106  and a relatively smaller scuff pad  154  located proximate each end of the first bottom plate member  106 . The first bottom plate member  106  also includes an aperture to which a first vacuum inlet filter screen  104  is connected. 
     The second anchor member  108  is preferably substantially identical to the first anchor member  101 . The second anchor member  108  preferably includes a second seal member  110  sandwiched between a second plate member  109  and a second bottom plate member  113  and operatively connected therebetween by fasteners  116 . The fasteners  116  extend through the second plate member  109 , the second seal member  110 , and the second bottom plate member  113  and are secured thereto. The second plate member  109 , the second bottom plate member  113 , and the second seal member  110  are preferably made of the same materials as the first plate member  102 , the first bottom plate member  106 , and the first seal member  103 , respectively. 
     The second seal member  110  includes sealing lips  110   a  and  112  proximate a bottom surface of the second seal member  110 . The bottom surface of the second seal member  110  is shown in  FIG. 5 . The sealing lip  110   a  is proximate the bottom perimeter of the second seal member  110  and forms the main seal between the second anchor member  108  and the surface of the anchorage structure to which it is attached. The sealing lips  112  are preferably concentric rings proximate the sealing lip  110   a  and provide backup seals in the event the main seal of sealing lip  110   a  is breached. Preferably, there are three rings of sealing lips  112  on the second seal member  110 , and the distance between the sealing lips  112  is preferably approximately 0.188 inch, but the distance could vary depending upon the size of the second seal member  110 . 
     Similarly, as shown in  FIG. 1 , the second plate member  109  includes a connector  153  and a fitting  153   a . The fitting  153   a  connects the connector  153  to the second plate member  109 , and the connector  153  is configured and arranged to connect to a second vacuum inlet hose  127 . Although not shown, the second bottom plate member  113  includes corresponding components as shown in  FIGS. 12-14  for the first bottom plate member  106 . The second bottom plate member  113  includes apertures through which portions of the second seal member  110  extend as scuff pads  155  to cushion and protect the surface of the anchorage structure so that it does not get scratched or damaged by the second bottom plate  113 . Preferably, there are three scuff pads  155  aligned along the longitudinal axis of the second bottom plate member  113 , and there is a relatively larger scuff pad  155  located proximate the middle of the second bottom plate member  113  and a relatively smaller scuff pad  155  located proximate each end of the second bottom plate member  113 . The second bottom plate member  113  also includes an aperture to which a second vacuum inlet filter screen  111  is connected. 
     A support  102   a , as shown in  FIG. 11 , is preferably a wedge-shaped member with a lip  102   b  extending outward from the bottom of the taller end. Preferably, two supports  102   a  are operatively connected to the first plate member  102 , preferably with screws, aligned along the longitudinal axis proximate the ends of the first plate member  102 . The supports  102   a  are positioned so that the lips  102   b  are pointed toward one another toward the middle of the first plate member  102 . 
     Similarly, a support  109   a  is preferably a wedge-shaped member with a lip  109   b  extending outward from the bottom of the taller end. Preferably, two supports  109   a  are operatively connected to the second plate member  109 , preferably with screws, aligned along the longitudinal axis proximate the ends of the second plate member  109 . The supports  109   a  are positioned so that the lips  109   b  are pointed toward one another toward the middle of the second plate member  109 . 
     As shown in  FIG. 15 , the lips  102   b  and  109   b  are configured and arranged to support each end of a housing plate  147 , which is preferably an upside down U-shaped plate member, and bolts  114  secure the ends of the housing plate  147  to the lips  102   b  and  109   b . In other words, the first plate member  102  and the second plate member  109  are interconnected by the housing plate  147 , which is also preferably made of aluminum, by bolts or other suitable fasteners. Preferably, the bolts  114  do not tightly secure the ends of the housing plate  147  against the supports  102   a  and  109   a  so that there is a small gap allowing the anchor members  101  and  108  to pivot approximately 15 degrees, approximately 7.5 degrees in each direction, about the shafts of the bolts  114  to allow the vacuum anchor  100  to conform to surfaces that are not planar such as curved surfaces. The housing plate  147  forms a cavity  149  between the ends of the housing plate  147  and the plate members  102  and  109 . A connector  145  is operatively connected to the housing plate  147  proximate a center portion of the housing plate  147  and extends in an upward direction therefrom. Preferably, the connector  145  is made of an alloy steel. The connector  145  is configured and arranged for attachment to a snap hook, a carabiner, or other suitable connector of a lifeline such as a horizontal lifeline, a lanyard, a self-retracting lifeline, or other suitable lifeline. 
     A guard plate  146  may be operatively connected to the housing plate  147  to protect an air cylinder bottle  115 , if used. An example of a suitable air cylinder bottle is a 48 CC 3,000 psi bottle of compressed air, Part No. 10519, manufactured by Pursuit Marketing Inc. in Des Plaines, Ill. The length of time the air cylinder bottle  115  lasts depends largely upon the surface of the anchorage structure and upon how many times the vacuum anchor  100  is sealed and resealed onto an anchorage structure.  FIG. 1  shows the vacuum anchor  100  with the guard plate  146 , and  FIG. 2  shows the vacuum anchor  100  without the guard plate  146 . A handle  148  may be operatively connected to the housing plate  147  to assist in carrying and positioning the vacuum anchor  100 . 
     The cavity  149  is configured and arranged to house several components of the vacuum anchor  100  shown in  FIG. 4 . The components are incorporated into the vacuum anchor  100  because they are physically connected and contained within the vacuum anchor  100  and not located remotely. An air input connector  142 , which is preferably a quick connector, extends outward from the cavity  149  proximate an adjacent side of the housing plate  147  to which the guard plate  146  is operatively connected. The air input connector  142  is configured and arranged for quick connection to an air hose  141  through which air flows from an air source and is preferably easily accessible. A pressure regulator  117  is in fluid communication with the air input connector  142  and is preferably adjustable but preset for the end user to approximately 85 to 100 psi to regulate the air pressure to a usable level. An example of a suitable pressure regulator is a ⅛ NPT pressure regulator set to 85 psi, Part No. R14 100 R85A manufactured by Norgren Inc. in Littleton, Colo. A pressure switch  118  is in fluid communication with the pressure regulator  117  and monitors the incoming air pressure to ensure it is high enough, preferably greater than 75 psi. An example of a suitable pressure switch is a ⅛ NPT pressure switch set to 75 psi, Part No. P110-55W3 manufactured by Wasco Inc. in Santa Maria, Calif. The pressure switch  118  is in an open position if the pressure level is greater than approximately 75 psi and is in a closed position if the pressure level is less than approximately 75 psi. 
     An air valve vacuum switch  120  is in fluid communication with a venturi  122 . An example of a suitable air valve vacuum switch is a ⅛ NPT silicone air valve vacuum switch, Part No. VP-700-30-PT manufactured by Airtrol Components Inc. in New Berlin, Wis. An example of a suitable venturi is Part No. JS-100M manufactured by Vaccon Company Inc. in Medfield, Mass. The venturi  122  receives air and creates a vacuum within the vacuum anchor  100 . A check valve  121  is in fluid communication with the venturi  122  and ensures that the vacuum flowing out of the venturi  122  and into a vacuum manifold  125  does not flow back into the venturi  122 . The vacuum manifold  125  is in fluid communication with a vacuum switch  128 , a filter  130 , and a vacuum output connector  158 . A check valve  123  ensures that the vacuum flowing through the filter  130  and into a vacuum control valve  129  does not flow back into the vacuum manifold  125 . 
     The check valves  121  and  123  are preferably one-way valves. An example of a suitable check valve is ¼ NPT quick exhaust valve, Part No. SZE2 manufactured by Humphrey Products Company in Kalamazoo, Mich. The check valve  121  ensures that the vacuum created by the venturi  122  enters the vacuum manifold  125  but does not exit the vacuum manifold  125 , and the check valve  123  ensures that the vacuum enters the vacuum control valve  129  but does not exit the vacuum control valve  129 . Should the air supply to the vacuum anchor  100  become interrupted, the vacuum will not be lost through the vacuum manifold  125  and the vacuum control valve  129 . This is a safety feature allowing time for connection to another anchorage point. Should the vacuum level become insufficient, a vacuum switch  128  activates an alarm. An example of a suitable vacuum switch is ⅛ NPT vacuum switch set to 20 inches Hg, Part No. V 110-31W3B-X/9863 manufactured by Wasco Inc. in Santa Maria, Calif. The vacuum switch  128  is in fluid communication with the vacuum manifold  125 , and the vacuum switch  128  is in an open position if the vacuum level is greater than approximately 20 inches Hg and is in a closed position if the vacuum level is less than approximately 20 inches Hg. Preferably, the vacuum level is approximately 25 inches Hg. The vacuum switch  128  reads both anchor members  101  and  108  since the anchor members  101  and  108  are in fluid communication with the vacuum manifold  125 . 
     The vacuum control valve  129  is in fluid communication with the vacuum manifold  125  and controls the vacuum level supplied to the anchor members  101  and  108 . An example of a suitable vacuum control valve is Part No. 8-42VF2 manufactured by Swagelok Company in Solon, Ohio. The vacuum control valve  129  is preferably a main ball valve. When it is desired to disconnect the vacuum anchor  100 , the vacuum control valve  129  is adjusted to decrease the vacuum thereby decreasing the resulting suction to allow the vacuum anchor  100  to be disconnected. The suction created by the vacuum could cause contaminants on the surface of the anchorage structure to enter the internal components of the vacuum anchor  100 , and the filter  130  is used to prevent contaminants from entering the internal components of the vacuum anchor  100 . An example of a suitable filter is Part No. B-4TF2-40 manufactured by Swagelok Company in Solon, Ohio. 
     A manifold  124  is in fluid communication with the vacuum control valve  129 , which supplies the vacuum to the manifold  124 . The manifold  124  is also in fluid communication with a vacuum gauge  131  and vacuum inlet hoses  126  and  127  interconnecting the manifold  124  and the anchor members  101  and  108 , respectively. The vacuum gauge  131  is calibrated to visually indicate the level of vacuum and is divided into a “ready” position  131   a  and a “warning do not use” position  131   b . An example of a suitable vacuum gauge is ⅛M-NPT CBM X 1½ inches Ashcroft® vacuum gauge, Part No. AC 15-1005-01B-30, manufactured by Dresser, Inc. in Addison, Tex. The vacuum gauge  131  measures the vacuum level proximate the manifold  124  to indicate if there is a leak in the device. Operatively connected to the manifold  124  are vacuum inlet hoses  126  and  127 , which are configured and arranged to operatively connect to the connectors  152  and  153  of the first anchor member  101  and the second anchor member  108 , respectively, which are in fluid communication with the manifold  124  as shown in  FIG. 6 . 
     An audio alarm  133 , as shown in  FIG. 7 , will sound if the level of vacuum or the air pressure is insufficient to audibly indicate that the vacuum anchor  100  may not be suitable for use as an anchorage point. An example of a suitable audio alarm is a 5 to 15 Volt direct current audio alarm, Part No. PS-723, manufactured by Mallory Sonalert Products, Inc. in Indianapolis, Ind. Preferably a single pole, double throw (hereinafter “SPDT”) momentary subminiature switch  138  is operatively connected to the vacuum control valve  129  and closes to arm the alarm  133  when the vacuum control valve  129  is opened. As shown in  FIG. 7 , the vacuum control valve  129  opens to arm the alarm by closing the SPDT momentary subminiature switch  138  and closes to disarm the alarm by opening the SPDT momentary subminiature switch  138 . Other suitable types of switches such as a single throw switch could also be used. An example of a suitable SPDT momentary subminiature switch is Part No. DC3C-M3AA manufactured by Cherry Electrical Components in Pleasant Prairie, Wis. When the SPDT momentary subminiature switch  138  is open, the alarm  133  will not sound. When the alarm  133  is armed, a momentary push button  139 , as shown in  FIGS. 7 and 15 , may be used as an override button and activated by pressing the button to disarm the alarm  133  when the vacuum anchor  100  is initially attached to the surface of the anchorage structure because the vacuum level is initially insufficient. An example of a suitable momentary push button is Part No. MSPF-101BC(0) manufactured by Tyco International (US) Inc. in Portsmouth, N.H. 
     A battery  135  contained in a battery housing  136  is used to power the audio alarm  133 . Preferably, four AA lithium iron disulfide batteries such as Part No. L91BP-4 manufactured by Energizer Holdings, Inc. in St. Louis, Mo. are used. A four drawer AA battery holder such as Part No. BX0027 manufactured by Bulgin Components PLC in Essex, England is preferably used. 
     A vacuum output connector  158 , which is preferably a quick connector, extends outward from the cavity  149  proximate a side of the housing plate  147  to which the handle  148  is operatively connected. The vacuum output connector  158  is configured and arranged for quick connection to a vacuum hose  162  through which vacuum flows from the vacuum anchor  100  and is preferably easily accessible. The vacuum hose  162  interconnects the vacuum anchor  100  to the auxiliary vacuum anchor  160 , to which vacuum is regulated by and supplied by the vacuum anchor  100 . The auxiliary vacuum anchor  160 , shown in  FIG. 8 , includes a vacuum input connector  161 , which is also preferably a quick connector, configured and arranged for quick connection to the vacuum hose  162  and is preferably easily accessible. 
     The auxiliary vacuum anchor  160  is much simpler since it relies upon the vacuum anchor  100 .  FIG. 16  is a schematic diagram of a pneumatic system of the auxiliary vacuum anchor  160 . The vacuum V from the vacuum output connector  158  of the vacuum anchor  100  flows through the vacuum hose  162  and enters the auxiliary vacuum anchor  160  via the vacuum input connector  161 . A check valve  163  ensures that the vacuum does not exit the auxiliary vacuum anchor  160 , and a vacuum control valve  164  controls the vacuum level supplied to the anchor members  168  and  169 . The vacuum then flows through a filter  165  and into a manifold  166 . The manifold  166  is in fluid communication with a vacuum gauge  167  and the anchor members  168  and  169 . The auxiliary vacuum anchor  160  operates similarly to vacuum anchor  100  with fewer components. The vacuum switch  128  also reads both anchor members  168  and  169  since the anchor members  168  and  169  are in fluid communication with the vacuum manifold  125 . 
     If it is desired to utilize the vacuum anchor  100  with an external air source rather than using the air cylinder bottle  115 , the air hose  141  may be disconnected from the air input connector  142 , and an external air source may be connected to the air input connector  142 . Alternatively, either an external air source or the air cylinder bottle  115  could be used as a backup air source should the other air source run out or otherwise fail. If the air cylinder bottle  115  and appropriate fittings were removed from the vacuum anchor  100 , vacuum anchor  100 ′ shown in  FIG. 3  would result and an external air source would be used. The components within the cavity of the vacuum anchor  100 ′ are preferably similar to the components within the cavity of the vacuum anchor  100 . The vacuum anchor  100 ′ is not described in detail as it is recognized that vacuum anchors  100  and  100 ′ are similarly constructed. Therefore, vacuum anchors  100  and  100 ′ may be interchangeable. 
     The vacuum anchor preferably requires an input pressure of 80 to 200 psi and consumes approximately 2.8 cubic feet per minute of compressed air because of the type of pressure regulator used in the preferred embodiment. It is recognized that this may vary depending upon the type of pressure regulator used. The vacuum switch is set to power the alarm if the vacuum level drops below 20 inches Hg. To calculate the capacity of the vacuum anchor, the area (in square inches) of the vacuum seal member(s) is multiplied by the vacuum level (in pounds per square inch). The total area of the vacuum seal members is preferably 360 square inches and the vacuum level of 20 inches Hg converted to psi is 9.82 psi. This results in a capacity of 3,535 pounds. This result applies to loads applied perpendicular to the surface of the anchorage structure. If the load is applied in a direction that would tend to slide the vacuum anchor, this result is reduced slightly, depending on the coefficient of friction between the pad and the surface. 
     In operation, as shown in  FIGS. 6 and 7 , air supplied by an air source A flows into the pressure regulator  117 . The air source A may be a small, integrally mounted or incorporated 3,000 psi compressed air cylinder bottle, an external compressed air source such as an air compressor or a large compressed air cylinder may be used, or any other suitable air source. The pressure switch  118  opens if the air pressure is greater than approximately 75 psi thereby preventing the alarm  133  from sounding and closes if the air pressure is less than approximately 75 psi thereby causing the alarm  133  to sound. The air then flows through the air valve vacuum switch  120  and into the venturi  122 . The venturi  122  receives air and creates a vacuum, which flows through a check valve  121  and into a vacuum manifold  125 . Once the vacuum manifold  125  reaches a level of approximately 25 inches Hg, the air valve vacuum switch  120  shuts off so that no compressed air is supplied to the venturi  122 , which conserves air. The check valve  121  prevents the vacuum from flowing back into the venturi  122 . A vacuum switch  128  opens if the vacuum level is greater than approximately 20 inches Hg thereby preventing the alarm  133  from sounding and closes if the vacuum level is less than approximately 20 inches Hg thereby causing the alarm  133  to sound. From the vacuum manifold  125 , the vacuum flows through the filter  130  and the check valve  123 , which prevents the vacuum from flowing back into the vacuum manifold  125 . The vacuum then flows through the main ball valve for the vacuum control  129  and through the manifold  124 . The vacuum gauge  131  indicates the vacuum level. The vacuum is then supplied to the anchor members  101  and  108 . The filters  104 ,  111 , and  130  prevent contaminants from entering the anchor members  101  and  108  and the vacuum anchor  100 . In addition, if desired, the vacuum anchor  100  may be used to supply vacuum to the auxiliary vacuum anchor  160  via the vacuum output connector  158 . The momentary push button  139  may be pressed, which opens the circuit to momentarily silence the alarm  133  while the vacuum anchor  100  is initially being connected. 
     The vacuum anchors  100 ,  100 ′, and  160  are preferably used for anchoring to an anchorage structure such as an aircraft, a storage tank, a ship, a submarine, a railcar, a truck, a roof, or other suitable anchorage structure. If used on aircraft, the surface to which the vacuum anchors  100 ,  100 ′, and  160  may be operatively connected to the fuselage, the wings, and the tail of aircraft without causing any damage to the aircraft. The vacuum anchors  100 ,  100 ′, and  160  should be operatively connected to the fuselage where supported by frames and stringers and on the upper surface of the wing between the spars. The vacuum anchors  100 ,  100 ′, and  160  are easily portable and reusable. 
     Unlike the prior art devices, the vacuum is created internally rather than externally and the vacuum level is monitored within the vacuum anchor rather than at a remote location. All of the components required for generating, monitoring, and maintaining the vacuum level are contained within the self-contained vacuum anchor. Prior art devices require a separate device that generates the vacuum, and the vacuum is then carried to the anchor pad via a hose. 
     To install the vacuum anchor(s), determine the location(s) of the vacuum anchor(s) and evaluate the strength of the anchorage structure. The anchorage structure must be capable of supporting the loads imposed by the vacuum anchor(s) should a fall occur. If used with a horizontal lifeline system, determine the span length and evaluate the required clearance. If an external air source is being used, the external air source should be located away from traffic and other hazards, and the air hose should be routed away from traffic and other hazards. The surface to which the vacuum anchor is to be attached should be cleaned to absorb excess moisture and remove loose debris, which could reduce the attachment to the anchorage structure and could be pulled into the vacuum anchor and corrode or damage the components. 
     To attach the vacuum anchor, position the vacuum control valve on the vacuum anchor in the “release pads” position. Place the vacuum anchor in the desired location on the desired anchorage structure and turn the vacuum control valve to the “attach pads” position. The audio alarm will sound thus indicating that the vacuum and resulting suction is not yet sufficient. The momentary push button may be pressed to temporarily silence the low vacuum level alarm during the initial attachment of the vacuum anchor to the anchorage structure. A slight downward pressure on the vacuum anchor members may be required to create an initial seal. If an audio alarm sounds during use, other than initially, an insufficient vacuum level or air pressure may be present and the vacuum anchor may not support the load should a fall occur. 
     The seal members  103  and  110  make a gas tight seal with the surface of the anchorage structure and the pressure between the surface and the seal members  103  and  110  becomes reduced thereby causing the anchor members  101  and  108  to be held against the surface by virtue of the atmospheric pressure acting on the anchor members  101  and  108 . When the anchor members  101  and  108  are secured to the surface, the force required to pull the anchor members  101  and  108  away from the surface is approximately 3,535 pounds as previously calculated. The maximum shear load the anchor members  101  and  108  can withstand before becoming disconnected is dictated largely by coefficient of friction between the seal members  103  and  110  and the surface. To reposition or release the vacuum anchor, the vacuum control valve should be turned to the “release pads” position. When the vacuum anchor has been repositioned, the vacuum control valve is turned to the “attach pads” position as previously stated. 
     The vacuum anchor  100  may be used by itself as an anchorage point secured to an anchorage structure  178  as shown in  FIG. 9 . An energy absorbing lanyard  181  or other suitable device is used to interconnect a harness  180  donned by a user and the connector of the vacuum anchor  100 . Alternatively, more than one vacuum anchor  100  may be used or the vacuum anchor  100  may be operatively connected to the auxiliary vacuum anchor  160  secured to the anchorage structure  178  for use with a horizontal lifeline system as shown in  FIG. 10 . If the auxiliary vacuum anchor  160  is used, it is connected to the vacuum anchor  100  via hose  162 . One end of a cable  185  is operatively connected to the vacuum anchor  100  with an energy absorber  183  and a cable tensioner  184 , and the other end of the cable  185  is operatively connected to the auxiliary vacuum anchor  160  with an energy absorber  183 . The cable  185  is preferably a synthetic lifeline, but it is recognized that any suitable material such as a rope or a metal cable may be used. An energy absorbing lanyard  181  or other suitable device is used to interconnect a harness  180  donned by a user and the cable  185 . 
     If two or more vacuum anchors are used for securing a horizontal lifeline, both vacuum anchors should be installed at approximately the same elevation so the horizontal lifeline system is not sloped more than five degrees. The cable tensioners are loosened and repositioned as required. The slack is removed from the cable and the cable is tensioned as is well known in the art. A connecting subsystem such as an energy absorbing lanyard is used to interconnect a safety harness donned by the user and the cable of the horizontal lifeline system. The vacuum anchor(s) should be positioned near the work location to minimize swing fall hazards, and the connecting subsystem length should be kept as short as possible to reduce the potential free fall and required clearance distance. 
     Levels of pressure and vacuum for use with the preferred components are listed for illustrative purposes only as it is recognized that the levels of pressure and vacuum may vary depending upon the components used. Therefore, the present invention is not limited to the levels of pressure and vacuum listed herein. The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.