SPRING ASSISTED BARRIER RAMS AND METHODS OF OPERATING THE SAME

Abstract

A barrier ram includes a frame and a barrier pivotably coupled to the frame. Two springs provide a combined torque very close to the torque provided on the barrier gate by gravity at all barrier positions relative to the frame. A method of operating such barrier is also provided.

Description

BACKGROUND

Anti-terrorist barrier rams have very heavy barriers, such as gates or arms, which are raised and lowered to open and close access to facilities, roads, and entrances. The barriers are pivotally mounted to a frame. Traditionally, due to the weight of the barriers, large hydraulic cylinders or actuators are used to provide sufficient torque to raise and lower them. These actuators take up space making it more difficult to incorporate such actuators in barrier ram frames that are shallow in depth, that would allow them to be shallow mounted, i.e., mounted in shallow depths from the surface. As such barrier rams that use smaller actuators for the operation and more precise control and positioning of the barrier, and that can be shallow mounted, are desired.

SUMMARY

An example embodiment barrier ram includes a frame, a barrier rotatable relative to the frame about a pivot axis between a first closed position to a second open position, a first spring rotatably coupled to the frame and the barrier, and a second spring rotatably coupled to the frame and the barrier. The first and second springs are compressed when the barrier is in the closed position. Together the first and second springs provide a first torque to the barrier about the pivot axis. A second torque acts on the barrier about the pivot axis due to gravity in the opposite direction from the first torque, and the difference between the first torque and the second torque is no greater than 25% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position. In another example embodiment, the difference between the first torque and second torque is no greater than 20% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position. In yet another example embodiment, the difference between the first torque and the second torque is no greater than 15% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position. In a further example embodiment, the difference between the first torque and the second torque is no greater than 10% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position. In yet a further example embodiment, the difference between the first torque and second torque is no greater than 5% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position. In one example embodiment, the second spring extends and compresses along a second spring axis, such that the second spring axis intersects the pivot axis when the barrier is in the closed position. In another example embodiment, the second spring has a second spring axis. When the second spring axis intersects the pivot axis it is an intersecting orientation, and when the barrier is in the closed position the second spring axis is offset no greater than 25 degrees from the intersecting orientation. In yet another example embodiment, the first spring extends and compresses along a first spring axis, and the first spring axis is in a first orientation and offset 30 degrees or less from a vertical axis when the barrier is in the closed position. The first spring axis is in a second orientation, different than the first orientation, and offset 30 degrees or less from the vertical axis when the frame is mounted horizontally, and the barrier is in the open position. In a further example embodiment, the first spring is housed in a first spring keeper, and the second spring is housed in a second spring keeper. Each spring keeper includes an outer barrel, and an inner barrel slideable within the outer barrel. A first centerer is fitted inside the outer barrel. The first centerer includes a first base and a first projection projecting axially from the first base for being received within a first end portion of its corresponding spring. A second centerer is fitted inside the inner barrel. The second centerer includes a second base and a second projection projecting axially from the second base for being received within a second end portion of its corresponding spring. In yet a further example embodiment, a layer of a wear resistant material covers the outer surface of the inner barrel that is received within the outer barrel. In another example embodiment, another layer of wear resistant material covers an inner surface of the inner barrel, and the layer and the another layer of wear resistant material extend beyond the inner barrel and are connected to each other at a location beyond the inner barrel.

In one example embodiment a barrier ram includes a frame, a barrier rotatable relative to the frame about a pivot axis between a first closed position and a second open position. A first spring is rotatably coupled to the frame and the barrier. The first spring compresses and extends along a first spring axis. A second spring is also rotatably coupled to the frame and the barrier. The second spring compresses and extends along a second spring axis. When the second spring axis intersects the pivot axis it is in an intersecting orientation, and when the barrier is in the closed position the second spring axis is within 25 degrees of the intersecting orientation or intersects the pivot axis. The first and second springs are compressed when the barrier is in the closed position, and the two springs together provide a first torque to the barrier about the pivot axis. A second torque about the pivot axis acts on the barrier due to gravity in an opposite direction from the first torque. In another example embodiment, the first spring axis is in a first orientation and offset 30 degrees or less from a vertical axis when the barrier is in the closed position, and the first spring axis is in a second orientation, different than the first orientation and offset 30 degrees or less from the vertical axis when the frame is mounted horizontally and the barrier is in the closed position. In yet another example embodiment, the first spring is housed in a first spring keeper, and the second spring is housed in a second spring keeper. Each spring keeper includes an outer barrel, an inner barrel slideable within the outer barrel, a first centerer fitted inside the outer barrel, and a second centerer fitted inside the inner barrel. The first centerer includes a first base and a first projection projecting axially from the first base for being received within a first end portion of its corresponding spring. The second centerer includes a second base and a second projection projecting axially from the second base for being received within a second end portion of its corresponding spring. In a further example embodiment, a layer of a wear resistant material covers an outer surface of the inner barrel that is received within the outer barrel. In yet a further example embodiment, another layer of wear resistant material covers an inner surface of the inner barrel, the layer and the another layer of wear resistant material extend beyond the inner barrel and connected to each other at a location beyond the inner barrel.

In one example embodiment, a method of operating a barrier including a frame and a barrier rotatable relative to the frame about a pivot axis between a closed position and an open position, a first spring and a second spring, includes providing a first torque with a first spring on the barrier about the pivot axis opposite a torque provided by gravity about the pivot axis on the barrier, and providing a second torque with the second spring about the pivot axis on the barrier opposite the torque provided by gravity, such that the combined first and second torque at all positions between the open and closed positions is within 25% of the torque provided by gravity. In another example embodiment, the combined first and second torque at all positions between the open and closed positions is within 20% of the torque provided by gravity. In yet another example embodiment, the combined first and second torque at all positions between the open and closed positions is within 15% of the torque provided by gravity. In a further example embodiment, the combined first and second torque at all positions between the open and closed positions is within 10% of the torque provided by gravity. In yet a further example embodiment, the combined first and second torque at all positions between the open and closed positions is within 5% of the torque provided by gravity.

In an example embodiment, a method of operating a barrier ram including a frame and a barrier rotatable about a pivot axis between a closed position and an open position relative to the frame, a first spring and a second spring, includes providing a first torque with a first spring on the barrier about the pivot axis opposite a torque provided by gravity about the pivot axis on the barrier, providing a second torque on the barrier with the second spring about the pivot axis opposite the torque provided by gravity, and providing a third torque using at least one actuator, the third torque being opposite the torque provided by gravity, and the third torque being not greater than 25% of the torque provided by gravity, wherein the first torque, the second torque and the third torque are sufficient for rotating the barrier toward the open position. In another example embodiment, the third torque is not greater than 20% of the torque provided by gravity. In yet another example embodiment, the third torque is not greater than 15% of the torque provided by gravity. In a further example embodiment, the third torque is not greater than 10% of the torque provided by gravity. In yet a further example embodiment, the third torque is not greater than 5% of the torque provided by gravity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of an example embodiment barrier ram.

FIGS. 2A, 2B, and 2C are cut away side views of the example embodiment barrier ram shown in FIG. 1 depicting a first spring when a barrier is in a closed position, a position between the closed and an open positions, and closed position, respectively.

FIGS. 3A, 3B, and 3C are cut away side views of the example embodiment barrier ram shown in FIG. 1 depicting a second spring when a barrier is in a closed position, a position between the closed and an open positions, and closed position, respectively.

FIG. 4 is a chart depicting torque applied by the first spring to the barrier of the example embodiment barrier ram and torque due to gravity acting on the barrier at different barrier angles.

FIG. 5 is a chart depicting torque applied by a second spring to the barrier of the example embodiment barrier ram and torque due to gravity acting on the barrier at different barrier angles.

FIG. 6 is a chart depicting the combined torque applied by the first spring and the second spring to the barrier of the example embodiment barrier ram and torque due to gravity acting on the barrier at different barrier angles.

FIG. 7 is an exploded view of an example embodiment spring including a spring keeper and spring centerers incorporated in the example embodiment barrier ram.

FIG. 8 is a cross-sectional view of an example embodiment spring housed in an example embodiment spring keeper.

FIG. 9 is a partial perspective view of an example embodiment spring keeper inner barrel housing an example embodiment spring.

FIG. 10 is a partial cross-sectional view of an inner barrel with a shim and centerer installed.

FIG. 11 is a cut away side view of the example embodiment barrier ram shown in FIG. 1 depicting a second spring when a barrier is in a 90-degree position for allowing the installation of the second spring at its free length.

DETAILED DESCRIPTION

In an example embodiment, a barrier ram includes a balancing system which includes springs that counteract the effects of gravity on the barrier ram. Barrier rams 10 as for example shown in FIGS. 1, 2A, 2B, 2C, 3A, 3B, and 3C include a frame 12 and one or more moveable barriers 14 such as a gate, arms, etc., that pivot about a pivot axis 16 of a pivot 18 to open and close relative to the frame. In an example embodiment, two compression springs are used. One or more actuators 19 are pivotably connected to the frame and the barrier and are used to provide a requisite torque to open and close the barrier. The two compression springs, include a first spring 20 and a second spring 22, and are positioned and oriented, as for example shown in FIG. 1, such that each spring has a desirable torque curve. One of the two springs is positioned closer to one side of the frame and the other closer to the other side of the frame. For illustrative purposes, when the barrier is down is a closed position, that position will also be sometimes referred to as a “road open position” as the barrier will not block the road or other facilities. Similarly, when the barrier is in an extended open position, that position will also sometimes be referred to as to “road closed position” since the barrier will be in a position blocking the passage to the road or other facilities. It should be understood that torque as used herein with the reference to the barrier refers to torque about the pivot axis 16 of the barrier. The two springs provide for torque in a first direction about the pivot axis, while gravity, due to the weight of the barrier, provides for torque about the pivot axis in a second direction opposite the first direction.

The first spring 20 is rotatably mounted to the frame and to the barrier such that is in a first position when the barrier is in the closed position, as for example shown in FIG. 2A. While in this position with the frame mounted horizontally, the axis of extension and compression of the first spring (the “first spring axis” 21), in an example embodiment, is in a first orientation within an angle 25 of 25 degrees of a vertical axis 23. The first spring is fully compressed, or almost fully compressed, when at this orientation. As the barrier moves from the closed position to the open position, the first spring rotates relative to the frame from the first orientation through a vertical position and past the vertical position to a second orientation when the barrier is in the second position as shown in FIG. 2A, 2B and 2C. In an example embodiment, when in the second orientation, the first spring axis 21 is within an angle 27 of 25 degrees from the vertical axis 23. In an example embodiment, when at the second orientation, the first spring is fully extended or near fully extended. In the shown example embodiment, the first spring is almost fully extended.

FIG. 4 is a chart of the torque on the barrier about the pivot axis due to gravity (noted by squares 30 defining a first spring torque curve) and applied by the first spring (noted by diamonds 32 defining a gravity torque curve) as measured at different barrier open angles relative to the frame. The torque provided by the first spring is in the opposite direction from the torque provided on the barrier due to gravity. When at 0 degrees, the barrier is in the closed position. As can be seen to FIG. 4, when the barrier is in the closed position (i.e., at 0 degrees), the torque provided by the first spring is close to the torque due to gravity. The difference between the torque provided by the first spring and the torque due to gravity is greater or greatest when the barrier is in the open position.

The second spring 22 is rotatably mounted to the frame and to the barrier with its spring axis, i.e., its axis of extension and compression (the “second spring axis”) 23 oriented at a first orientation so as to intersect the pivot axis, or pass very close or adjacent to the pivot axis 16, when the barrier is in the closed position, as for example shown in FIG. 3A. For reference, when the second spring axis is intersects the pivot axis, the second pivot axis it as the intersecting orientation 29, as for example shown in FIG. 3A. When the barrier is in the closed position, the second spring axis 23 is at a first orientation which is coaxial with the intersecting axis 29 or offset from the intersecting axis by an offset angle 31. In the example embodiment shown in FIG. 3A, the second spring axis 23 is coaxial with the intersecting axis 29. In an example embodiment, when in the first orientation, the offset angle is no greater than 30 degrees. In a further example embodiment, the offset angle is no greater than 25 degrees. In another example embodiment, the offset angle is no greater than 20 degrees. In another example embodiment, the offset angle is no greater that 15 degrees. In yet another example embodiment, the offset angle is no greater than 10 degrees. In a further example embodiment, the offset angle is no greater than 5 degrees. As the barrier is opening relative to the frame, the offset angle 31 increases. When the barrier is in the open position, the second spring axis is at a second orientation offset by the angle 31 from the intersecting axis, which is greater than the offset angle 31 when in the first orientation.

When in the closed position (at 0 degrees) as shown in FIG. 3A, the second spring is in a compressed, or fully compressed, position. When the barrier in the open position the second spring is less compressed and more extended, as shown for example in FIG. 3C. FIG. 5 is a chart depicting the torque applied to the barrier about the pivot axis by the second spring (denoted by diamonds 34 defining a second spring torque curve) and the torque due to gravity (denoted by squares 30 defining the gravity torque curve) about the pivot axis as measured when the barrier is oriented at different angles relative to the frame. As can be seen from FIG. 5 when the barrier is in the open position, the torque provided by the second spring is close to the torque due to gravity. The difference between the torque provided by the second spring and the torque due to gravity is greater, or greatest, when the barrier is in the closed position (i.e., at 0 degrees). The torque provided by the second spring is the lowest when the second spring is compressed, or fully compressed, when the barrier is in the closed position. As the barrier is opened from the closed position, the second spring axis rotates further away from the pivot axis, i.e., the angle 31 increases. As such, the torque provided by the second spring increases and then decreases as the second spring approaches full extension.

To summarize, the first spring 20 reaches near full extension, or full extension, when the barrier is raised into the open (or road closed) position, exerting no, or minimal, torque on the barrier about the pivot, as for example shown in FIG. 2C. When the barrier 14 is in the fully down position, as for example shown in FIG. 3A, the second spring 22 is fully compressed, or almost fully compressed, with its second spring axis 26 oriented to intersect the pivot axis 16 of the barrier or pass very close to the pivot axis and thus, applies nearly no torque to the barrier about pivot axis despite the first spring being compressed or fully compressed. As the barrier is raised, the effective lever arm of the second spring grows, as the second spring axis rotates further away from the pivot axis. In an example embodiment, as shown in FIG. 3C, when the barrier is in the fully up position (road closed position) the second spring is still compressed (though not at full compression).

The first and second springs are selected such that their combined torque (the “combined spring torque”) 36 defines a combined torque curve about the pivot axis that matches or is very close to the torque curve due to gravity as the barrier rotates between its open and closed positions, as for example shown in FIG. 6. As stated before, the torque created by the springs is opposite the torque due to gravity (the “gravity torque”). In an example embodiment, the difference in torque between the combined spring torque 36 and the gravity torque at any angle between and including the barrier closed and open positions is not greater than 25% of either the combined spring torque or the gravity torque. In a further example embodiment, this difference in torque is not greater than 20% of either the combined spring torque or the gravity torque. In yet a further example embodiment, this difference in torque is not greater than 15% of either the combined spring torque or the gravity torque. In another example embodiment, this difference in torque is not greater than 10% of either the combined spring torque or the gravity torque. In yet a further example embodiment, this difference in torque is no greater than 5% of either the combined spring torque or the gravity torque. In any of the aforementioned example embodiments, the difference in torque is the stated percentage of the smaller of the combined spring torque and the gravity torque. In other words, at any angle between the open and closed position, the torque required to be provided by at least one actuator 19 to open the barrier, will be not greater than a percentage of the combined spring torque or the gravity torque, or a percentage of the smaller of the combined spring torques or the gravity torque. In one example embodiment, this percentage is not greater than 25%. In another example embodiment, this percentage is not greater than 20%. In yet another example embodiment, this percentage is not greater than 15%. In a further example embodiment, this percentage is not greater than 10%. In yet a further example embodiment, this percentage is not greater than 5%. In one embodiment, at each angle, the springs offset at least 75% of the torque due to gravity. In another embodiment, the offset is at least 80% of the torque due to gravity. In yet another example embodiment, the offset is at least 85%. In a further example embodiment, the offset is at least 90%. In yet another example embodiment, the offset is at least 95%. As a result, the frames may be made shallower as the barrier may be operated using smaller actuators, due to the smaller required torque to open the barrier, which take up less space.

At full compression, the springs store large amounts of energy. In an example embodiment they each have a rate greater than 350 lb/in, and in a further example embodiment they each have a rate in the range of 350 lb/in to 750 lb/in. In one example embodiment, the springs have a rate greater than 500 lb/in. In another example embodiment each spring had a free length of 24 inches and has an inner diameter of about a 3.75. The diameter of the wire forming the spring is in the range of about 0.75 to about 1 inch. Thus, the outer diameter is in the range of about 5.25 to about 5.75 inches. In addition, due to geometry constraints inside a barrier ram, the springs are at risk of buckling due to their length to diameter ratio. To prevent the springs from buckling, in an example embodiment, each spring is housed in a keeper 40, as for example shown in FIGS. 7 and 8. Buckling would inhibit the spring's ability to properly balance the barrier. The keepers provide the springs with side support preventing them from bucking. The keepers also serve to store the high energy of the springs should the springs break or buckle. As a result, the keepers ensure optimum spring performance and operational life. In an example embodiment, each spring keeper 40 includes an inner barrel 42 and an outer barrel 44. The inner barrel has a first open end 46 for receiving a first end of a spring 20, 22. A second end 48 of the inner barrel is closed, or restricted, defining a base for retaining the first end of the spring within the barrel. A clevis or other means 50 extends from the second end of the first barrel for connecting to the frame or the barrier. The outer barrel 42 has a first open end 52 for receiving a second end of a spring 20,22. A second end 54 of the outer barrel is closed, or restricted, for retaining a second end of the spring within the barrel. A clevis or other means 56 extends from the second end of the second barrel for connecting to the frame or the barrier. The inner barrel has an outer surface having a smaller diameter than the inner surface of the outer barrel. In this regard, the first end of the inner barrel can slide within the outer barrel past the first end of the outer barrel. In an example embodiment, each barrel is formed from a wear resistant material. In one example embodiment, each barrel is made from steel. In another example embodiment, each barrel is made from aluminum. In a further example embodiment, each barrel is made from titanium.

Prior to placing the spring in each of the barrels, a first centerer 58 is placed in the inner barrel and a second centerer 60 is placed in the outer barrel. Each centerer has a circular base 58A, 60A and a protrusion 58B, 60B protruding axially from the base portion. Each spring has an inner diameter and an outer diameter. Each protrusion has an outer diameter slightly smaller than the inner diameter of the spring so that it can be received within its corresponding spring end inner diameter. Each base has a diameter larger than the diameter of its corresponding protrusion and slightly smaller than the inner diameter of its corresponding barrel, such that when it is placed within the barrel it has minimal or no sideway play. The centerers serve to minimize the sideway play of each spring as it compresses and extends.

In an example embodiment, the outer surface 70 of the inner barrel is lined with a protective wear layer 72, as for example shown in FIGS. 8 and 9. In an example embodiment, the protective wear layer used is also one that fosters the sliding of the inner barrel within the outer barrel. In an example embodiment, the protective wear layer is a layer of ultra-high molecular weight polyethylene (UMHW). In another example embodiment, the protective wear layer may be a layer of Delrin or may be a polytetrafluoroethylene (PTFE) coating. In one example embodiment, as shown in FIGS. 8 and 9, the inner surface of the inner barrel is also lined with a protective wear layer. With this example embodiment, the two wear protective layers may extend from proximate the second end of the inner barrel to beyond the first end of the inner barrel, as for example shown in FIGS. 8 and 9. In an example embodiment, they two layers extend ¾ inch beyond the first end of the inner barrel and the portions of the two layers extending beyond the first end are connected to each other to prevent them from peeling away from each other. In one example embodiment, these portions are riveted to each other with rivets 74.

To form a spring housed in a spring keeper, the centerers are placed in the first and second barrels so that their bases 58A, 60A are over their corresponding barrel second ends and with their protrusions 58B, 60B, extending from their corresponding base in a direction toward their corresponding barrel's second end. The spring is inserted through the first end of each barrel and the inner barrel is slid within the outer barrel. Each protrusion 58B, 60B is received within a corresponding end of the spring. In one example barrels are sized such that when the spring is fully extended, a portion of the inner barrel is within the outer barrel. In another example embodiment, when compressed an entire spring can fit within its corresponding inner barrel.

The spring keepers also allow for the installation of one or more shims 61 to give the springs more preload, if necessary. This can help to adjust-in the spring torque curves as necessary. The shims 61 are simply round stocks of metal that slip inside the spring keepers prior to the installation of the centerers and the spring such that they are sandwiched between the centerer and the second end of the corresponding barrel, as for example shown in FIG. 10. The shims 61 may be installed one on both of the inner and outer barrels.

Typical barriers aren't capable of rotating much past their open (road closed) position. But when in the open position, the second spring will still be highly compressed. As such, it would be very difficult and dangerous to install a second spring of its size with the large necessary pre-tension when barrier is in the open position. To address this issue, in an example embodiment, the barrier can be lifted at an angle 80 to a full 90 degrees (perpendicular to the roadway) or an angle 80 almost perpendicular to the roadway, as for example shown in FIG. 11. When at this position, the second spring can be installed at its free, naturally extending, length. The first spring can be installed at an angle much closer to the road closed position when it is also in the almost fully extended position.

As will be understood by those skilled in the art, the size of springs selected and thus, the force generated by them will depend on the weight of the barrier that they will assist in opening and the torque generated by gravity on the barrier about its pivot axis. In this regard the springs can offset the torque due to gravity at each angle of the barrier relative to the frame.

While this invention has been described in detail with particular references to exemplary embodiments thereof, the exemplary embodiments described herein are not intended to be exhaustive or to limit the scope of the invention to the exact forms disclosed. Persons skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structures and methods of assembly and operation can be practiced without meaningfully departing from the principles, spirit, and scope of this invention, as set forth in the following claims. Although relative terms such as “outer,” “inner,” “upper,” “lower,” “below,” “above,” and similar terms have been used herein to describe a spatial relationship of one element to another, it is understood that these terms are intended to encompass different orientations of the various elements and components of the invention in addition to the orientation depicted in the figures. Additionally, as used herein, the term “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. Furthermore, as used herein, when a component is referred to as being “on” another component, it can be directly on the other component or components may also be present therebetween. Moreover, when a component is referred to as being “coupled” to another component, it can be directly attached to the other component or intervening components may be present therebetween.

Claims

1. A barrier ram comprising: a frame;a barrier rotatable relative to the frame about a pivot axis between a first closed position to a second open position;a first spring rotatably coupled to the frame and the barrier; anda second spring rotatably coupled to the frame and the barrier, wherein the first and second springs are compressed when the barrier is in the closed position, and wherein said first and second spring together provide a first torque to the barrier about the pivot axis and wherein a second torque acts on the barrier about the pivot axis due to gravity in the opposite direction from the first torque, wherein the difference between the first torque and second torque is no greater than 25% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position.

2. The barrier ram of claim 1, wherein the difference between the first torque and second torque is no greater than 20% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position.

3. The barrier ram of claim 1, wherein the difference between the first torque and second torque is no greater than 15% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position.

4. The barrier ram of claim 1, wherein the difference between the first torque and second torque is no greater than 10% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position.

5. The barrier ram of claim 1, wherein the difference between the first torque and second torque is no greater than 5% of one of the first torque and the second torque when the barrier is at any position from the closed position to the open position.

6. The barrier ram of claim 1, wherein the second spring extends and compresses along a second spring axis, wherein the second spring axis intersects the pivot axis when the barrier is in the closed position.

7. The barrier ram of claim 6, wherein the first spring extends and compresses along a first spring axis, and wherein the first spring axis is in a first orientation and offset 30 degrees or less from a vertical axis when the barrier is in the closed position, and the first spring axis is in a second orientation, different than the first orientation and offset 30 degrees or less from the vertical axis when the frame is mounted horizontally and the barrier is in the open position.

8. The barrier ram of claim 1, wherein the second spring has a second spring axis, wherein when the second spring axis intersects the pivot axis it is an intersecting orientation, and wherein when the barrier is in the closed position the second spring axis is within 25 degrees of the intersecting orientation.

9. The barrier ram of claim 8, wherein the first spring extends and compresses along a first spring axis, and wherein the first spring axis is in a first orientation and offset 30 degrees or less from a vertical axis when the barrier is in the closed position, and the first spring axis is in a second orientation, different than the first orientation and offset 30 degrees or less from the vertical axis when the frame is mounted horizontally and the barrier is in the open position.

10. The barrier ram of claim 1, wherein the first spring is housed in a first spring keeper, wherein the second spring is housed in a second spring keeper, and wherein each spring keeper comprises, an outer barrel,an inner barrel slideable within the outer barrel,a first centerer fitted inside the outer barrel, said first centerer comprising a first base and a first projection projecting axially from the first base for being received within a first end portion of its corresponding spring, anda second centerer fitted inside the inner barrel, said second centerer comprising a second base and a second projection projecting axially from the second base for being received within a second end portion of its corresponding spring.

11. The barrier ram of claim 1, further comprising a layer of a wear resistant material covering the outer surface of the inner barrel that is received within the outer barrel.

12. The barrier ram of claim 11, further comprising another layer of wear resistant material covering an inner surface of the inner barrel, said layer and another layer of wear resistant material extending beyond the inner barrel and connected to each other at a location beyond the inner barrel.

13. A barrier ram comprising: a frame;a barrier rotatable relative to the frame about a pivot axis between a first closed position and a second open position;a first spring rotatably coupled to the frame and the barrier, the first spring compressing and extending along a first spring axis; anda second spring rotatably coupled to the frame and the barrier, wherein the second spring compresses and extends along a second spring axis, wherein when the second spring axis intersects the pivot axis it is an intersecting orientation, and wherein when the barrier is in the closed position the second spring axis is within 25 degrees of the intersecting orientation or intersects the pivot axis, wherein the first and second springs are compressed when the barrier is in the closed position, and wherein said two springs together provide a first torque to the barrier about the pivot axis and wherein a second torque about the pivot axis acts on the barrier due to gravity in an opposite direction from the first torque.

14. The barrier ram of claim 13, wherein the first spring axis is in a first orientation and offset 30 degrees or less from a vertical axis when the barrier is in the closed position, and the first spring axis is in a second orientation, different than the first orientation and offset 30 degrees or less from the vertical axis when the frame is mounted horizontally and the barrier is in the closed position.

15. The barrier ram of claim 13, wherein the first spring is housed in a first spring keeper, wherein the second spring is housed in a second spring keeper, and wherein each spring keeper comprises, an outer barrel,an inner barrel slideable within the outer barrel,a first centerer fitted inside the outer barrel, said first centerer comprising a first base and a first projection projecting axially from the first base for being received within a first end portion of its corresponding spring, anda second centerer fitted inside the inner barrel, said second centerer comprising a second base and a second projection projecting axially from the second base for being received within a second end portion of its corresponding spring.

16. The barrier ram of claim 15, further comprising a layer of a wear resistant material covering an outer surface of the inner barrel that is received within the outer barrel.

17. The barrier ram of claim 16, further comprising another layer of wear resistant material covering an inner surface of the inner barrel, said layer and another layer of wear resistant material extending beyond the inner barrel and connected to each other at a location beyond the inner barrel.

18. A method of operating a barrier comprising a frame and a barrier rotatable about a pivot axis between a closed position and an open position relative to the frame, a first spring, and a second spring, wherein as the barrier opens and closes and it is exposed to a torque due to gravity about the pivot axis, said method comprising: providing a first torque with a first spring on the barrier about the pivot axis opposite the torque provided by gravity; and

19. The method as recited in claim 18, wherein the combined first and second torque at all positions between the open and closed positions is within 20% of the torque provided by gravity.

20. The method as recited in claim 18, wherein the combined first and second torque at all positions between the open and closed positions is within 15% of the torque provided by gravity.

21. The method as recited in claim 18, wherein the combined first and second torque at all positions between the open and closed positions is within 10% of the torque provided by gravity.

22. The method as recited in claim 18, wherein the combined first and second torque at all positions between the open and closed positions is within 5% of the torque provided by gravity.

23. A method of operating a barrier comprising a frame and a barrier rotatable about a pivot axis between a closed position and an open position relative to the frame, a first spring, and a second spring, wherein as the barrier opens and closes it is exposed to a torque about the pivot axis due to gravity: providing a first torque with a first spring on the barrier about the pivot axis opposite the torque provided by gravity;

24. The method as recited in claim 23, wherein said third torque is not greater than 20% of the torque provided by gravity.

25. The method as recited in claim 21, wherein said third torque is not greater than 15% of the torque provided by gravity.

26. The method as recited in claim 21, wherein said third torque is not greater than 10% of the torque provided by gravity.

27. The method as recited in claim 21, wherein said third torque is not greater than 5% of the torque provided by gravity.