Abstract:
A hold open rod is provided. The hold open rod includes an outer tube, a lock body connected to the outer tube, an inner tube, slidingly disposed within the outer tube and lock body, the inner tube having an outer surface, and a friction pad captured between the lock body and the outer surface of the inner tube. A method for damping movement of a telescoping rod is also provided. The method includes attaching the locking body to an outer tube, configuring the outer tube and the inner tube to move with respect to each other in a telescoping manner, fitting a damper between an outer diameter of an inner tube and a locking body, and fitting the damper to frictionally engage the outer diameter of the inner tube and the locking body.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part (CIP) of pending application Ser. No. 12/555,200, entitled “Hold Open Rod,” filed Sep. 8, 2009 which is a continuation-in-part (CIP) of pending application Ser. No. 12/135,778, entitled “Device And Method Of Mechanically Dampening A Hold Open Rod,” filed on Jun. 9, 2008, the disclosures of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to rods, struts, etc. More particularly, the present invention relates to a hold open rod. 
       BACKGROUND OF THE INVENTION 
       [0003]    Door closers are used to close a door after being opened manually or automatically. Generally, door closers include a cylinder having a piston connected to a piston rod within the cylinder. The piston is normally biased by a compression spring. The opposed ends of the cylinder and the piston rod may be suitably connected between a door frame and its door. The opening of the door causes the piston to be rectilinearly displaced within the inner surface of the cylinder whereby the connected piston rod is extended beyond the end of the cylinder, thereby compressing the spring. The compression spring, acting on the piston in its compressed state, normally functions to return the door to its closed position as the door is released after the opening of the door. 
         [0004]    In certain applications, hold open rods are used to control the rate at which a door, a hatch, etc., closes. To control the closing of a door, pneumatic springs or hydraulic-type dampeners have been used to dampen the movement of hold open rods. The retracting momentum of the piston is typically cushioned by compression of fluid, such as air or oil inside the cylinder tube to create a damping resistance opposite the force that propels the door to close for better control of the speed and force at which the door closes. 
         [0005]    A known problem regarding known dampeners is that the fluid used in these devices introduces an opportunity for undesirable leakage. In addition, these hydraulics and pneumatics have seals, wipers and o-rings that wear and require frequent maintenance and replacement. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with one embodiment of the invention, a hold open rod is provided. The hold open rod includes an outer tube, a lock body connected to the outer tube, an inner tube, slidingly disposed within the outer tube and lock body, the inner tube having an outer surface, and a friction pad captured between the lock body and the outer surface of the inner tube. 
         [0007]    In accordance with yet another embodiment of the invention, a hold open rod may be provided. The hold open rod includes an outer tube, a means for locking connected to the outer tube, an inner tube, slidingly disposed within the outer tube and the means for locking the inner tube having an outer surface, and a means for dampening captured between the means for locking and the outer surface of the inner tube. 
         [0008]    In accordance with still another embodiment of the invention, a method for damping movement of a telescoping rod may also be provided. The method may include attaching the locking body to an outer tube, configuring the outer tube and the inner tube to move with respect to each other in a telescoping manner, fitting a damper between an outer diameter of an inner tube and a locking body, and fitting the damper to frictionally engage the outer diameter of the inner tube and the locking body. 
         [0009]    There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
         [0010]    In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
         [0011]    As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a cross-sectional view illustrating a door in a closed configuration suitable for use with a hold open rod according to an embodiment of the invention. 
           [0013]      FIG. 2  is a cross-sectional view illustrating the door according to  FIG. 1  in an open configuration. 
           [0014]      FIG. 3  is a cross-sectional view illustrating a hold open rod according to an embodiment of the invention. 
           [0015]      FIG. 4  is a partially cutaway perspective view of the hold open rod shown in  FIG. 3 . 
           [0016]      FIG. 5  is a cross-sectional perspective view of the cross-section of the hold open rod shown in  FIG. 3 . 
           [0017]      FIG. 6  is a cross-sectional view of a hold open rod according to another embodiment of the invention. 
           [0018]      FIG. 7  is a cross-sectional perspective view of the hold open rod according to the embodiment depicted in  FIG. 6 . 
           [0019]      FIG. 8  is a cross-sectional view of a hold open rod according to another embodiment of the invention. 
           [0020]      FIG. 9  is a cross-sectional perspective view of the hold open rod according to the embodiment depicted in  FIG. 8 . 
           [0021]      FIG. 10  is a perspective view of a friction pad according to an embodiment of the invention. 
           [0022]      FIG. 11  is an isometric cross-sectional view of the hold open rod according to an embodiment of the invention. 
           [0023]      FIG. 12  is an isometric cross-sectional view of a release assembly according to the embodiment depicted in  FIG. 11 . 
           [0024]      FIG. 13  is an isometric cross-sectional view of an end fitting suitable for attachment to a proximal end of the hold open rod. 
           [0025]      FIG. 14  is an isometric cross-sectional view of an end fitting suitable for attachment to a distal end of the hold open rod. 
           [0026]      FIG. 15  is an isometric view of a hold open rod in an extended position. 
           [0027]      FIG. 16  is an isometic view of a hold open rod in a retracted position. 
           [0028]      FIG. 17  is a cross-sectional view of hold open assembly in accordance with an embodiment of the invention. 
           [0029]      FIG. 18 . is an isometric cross-sectional view of the hold open assembly shown in  FIG. 17 . 
           [0030]      FIG. 19  is a cross-sectional view of hold open assembly in accordance with another embodiment of the invention. 
           [0031]      FIG. 20  is a detailed partial view of the hold open assembly shown in  FIG. 19 . 
           [0032]      FIG. 21  is an isometric view of damping pad in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. 
         [0034]      FIG. 1  is a cross-sectional view illustrating a door, hatch, etc.,  10  in a closed configuration suitable for use with a hold open rod  12  according to an embodiment of the invention. As shown in  FIG. 1 , the door  10  may be disposed in a vehicle such as an aircraft, bus, ship, train, or the like. For example, door  10  is disposed in a fuselage of an aircraft. In other examples, the door  10  may be an access panel, cover, cowling, etc., for an engine nacelle, luggage compartment or other such compartment in an aircraft, vehicle, etc. In addition, the hold open rod  12  may be utilized in other structures such as buildings. However, due to the advantageous reduction in weight and ease of maintenance, the hold open rod  12  is particularly useful in aircraft and vehicles. According to a preferred embodiment, hold open rod  12  includes an inner tube  16  and an outer tube  18  Inner tube  16  and outer tube  18  are in axial alignment and slide relative to one another in a telescoping manner. 
         [0035]    The hold open rod  12  may be attached to the door  10  by a door fitting  20  pivotally connected to the inner tube  16 . The hold open rod  12  may be attached to the fuselage, engine nacelle, etc., by a bracket  22  pivotally connected to the outer tube  18 . The converse attachment orientation is also contemplated by the present invention. 
         [0036]    As shown in  FIG. 2 , the door  10 , may swing open via a hinge  24 , for example. In response to the door  10  being opened, the inner tube  16  may telescope out from the outer tube  18 . In the particular example shown, in the open configuration, the door  10  is biased to close at least by gravity acting upon the door  10 . In this or other examples, biasing of the door  10  may be provided by a spring or actuator. The hold open rod  12  facilitates maintaining the door  10  in the open configuration by providing resistance. Specifically, the hold open rod  12  provides resistance to the inner tube  16  sliding into the outer tube  18 . 
         [0037]    While  FIGS. 1 and 2  show the hold open rod  12  retracted in response to the door  10  being in a closed configuration and extended in response to the door  10  being in an open configuration, in other examples the hold open rod  12  may be extended in response to the door  10  being closed. That is, depending upon where the hold open rod  12  is attached to the door  10  and/or a frame of the door  10 , the bias of the door  10 , the addition of any suitable linkage or linkages, the hold open rod  12  may be configured to extend or retract in response to the door  10  being opened or closed. 
         [0038]      FIG. 3  is a cross-sectional view illustrating a hold open rod  12  according to an embodiment of the invention. One or more friction pads  28  are disposed between an inner surface  30  of the outer tube  18  and an outer surface  32  of the inner tube  16 . When the hold open rod  12  is in use, the friction pads  28  are squeezed between the inner surface  30  and the outer surface  32  with sufficient force to generate a predetermined amount of frictional resistance to the sliding motion of the outer tube  18  relative to the inner tube  16 . In this manner, movement of the outer tube  18  relative to the inner tube  16  may be dampened or stopped. 
         [0039]    The inner tube  16  also includes a head  40  to retain the friction pads  28 . The head  40  includes a pair of pad retaining flanges  42  and  44  to retain the friction pads  28  therebetween. The head  40  further includes a pad seat  46 . In an embodiment of the invention, the pad seat  46  includes a tapered annular surface that tapers radially outwardly at angle θ. The angle θ may include any suitable angle such as about 1° to about 7°. In various embodiments, the inner bearing surface of pad seat  46  may be straight, tapered or frusta-conical. In use, as the inner tube  16  is moved in direction “A” relative to the outer tube  18 , friction acting between the friction pads  28  and the inner surface  30  urges the friction pads  28  in direction “B” relative to the inner tube  16 . As the friction pads  28  traverse the pad seat  46  in direction “B”, the friction pads  28  are squeezed between the inner surface  30  and the outer surface  32  to a greater extent. Optionally, the friction pads  28  may also be tapered or frusta-conically shaped. For example, the friction pads  28  may also be tapered at angle θ. 
         [0040]    Additionally, the hold open rod  12  may optionally include a spring  50  disposed in a spring retaining seat  52 . If included, the spring  50  may be disposed between the spring retaining seat  52  and the friction pads  28  to urge the friction pads  28  radially, outwardly. In a particular embodiment, the spring  50  includes an elastomeric annular ring having one or more flange portions that act as resilient members to urge the friction pads  28  radially, outwardly. 
         [0041]    In various embodiments of the invention, the head  40  of the inner tube  16  may be removably or threadedly attached to the inner tube  16  via a threaded insert  52 . This allows for the head  40  and the threaded insert to be made from a different material than the inner tube  16 . For example, the inner tube  16  may include an aluminum, magnesium, and/or titanium alloy to reduce weight while the head  40  may include a stainless steel and/or bronze alloy to provide wear, strength, and/or machining properties. In some embodiments, a portion of the inner tube  16  may be hollow. This may reduce weight and/or enable the manufacturing and maintenance of the hold open rod  12  to be cost efficient. In other embodiments, however, the inner tube  12  may be one solid piece of material. 
         [0042]    In one embodiment, pad seat  46  tapers radially outwardly at angle θ. Again, the friction pads  28  may, optionally, also be tapered at angle θ, which is based on a variety of factors such as, for example, modulus of elasticity of the friction pads  28 , frictional coefficient between the friction pads  28  and the inner surface  30 , the frictional coefficient between the friction pads  28  and the outer surface  32 , the expected load on the hold open rod  12 , the predetermined amount of frictional resistance, empirical data, and the like. For example, the pad seat  46  may taper radially outwardly at both ends or may taper radially inwardly at both ends from about a center portion of the pad seat  46 . 
         [0043]    In response to the door being opened or closed, the inner tube  16  is moved with respect to the outer tube  18  in a telescoping manner. As the tubes move axially, friction urges the friction pad  28  to translate along the pad seat  46 . This translation of the friction pad  28  is again opposed by friction. In a particular example, in response to the inner tube  16  moving in direction “A” with respect to outer tube  18 , the friction urges the friction pad  28  to translate along the pad/tube interface. As the friction pad  28  translates along the tapered pad seat  46 , a gap or distance separating the inner surface  30  from the outer surface  32  is reduced. The compression of the friction pads  28  provides friction between the friction pads  28  and inner tube  16  outer wall, thereby creating a dampening effect to slow or stop the movement of the telescoping tubes. In general, a transverse load, such as the friction pads  28  being urged outwardly, is produced from an axial force resulting from extending and/or retracting of the hold open rod  12 . In a particular example, the dampening effect is sufficient to hold the door  10  (shown in  FIGS. 1 and 2 ) open against the bias of the door  10  but not so great to hamper closing of the door  10  by an operator, for example. 
         [0044]    If included, the optional spring  50  may further urge the friction pads  28  outwards and against the inner surface  30 . This outward urging of the spring  50  may maintain the outward thrust of the friction pads  28  against the inner surface  30  at a predetermined minimum amount of outward thrust. In turn, this predetermined minimum amount of outward thrust acts to “pre-load” the friction pads  28  against the inner surface  30 . In addition, the elastic properties or the spring  50  may offset thinning of the friction pads  28  due to abrasion, for example. 
         [0045]      FIG. 4  is a partially cutaway perspective view of the hold open rod  12  shown in  FIG. 1 . As shown in  FIG. 4 , the friction pads  28  may include two complimentary halves which encase the outer surface of the inner tube  16 . In response to these complimentary halves of the friction pads  28  being urged apart and against the inner surface  30 , the resistance to the sliding motion of the inner tube  16  relative to the outer tube  18  may be increased. In this manner, the hold open rod  12  may be used to control the rate at which the door  10  opens and/or closes. 
         [0046]      FIG. 5  is a cross-sectional perspective view of the mechanical dampening device shown in  FIG. 3 . The shape and material of the friction pads  28  and tube head  40  control the coefficient of friction and therefore, control the dampening feature of the hold open rod  12 . The friction pads  28  may be shaped to complement the outer surface of the head  40  such that the desired dampening occurs. As appreciated by one of ordinary skill in the art, the friction pads  28  may be made of an elastomeric material, such as ethylene vinyl acetate, for example. 
         [0047]      FIG. 6  is a cross-sectional view illustrating hold open rod  12  according to another embodiment. In this embodiment, hold open rod  12  includes an outer tube  18 , an inner tube  16  and an inner rod  70 . The inner rod  70  is secured to the outer tube  18  via a adapter  72 . Specifically, the proximal end of the inner rod  70  is secured in the adapter  72  and the adapter  72  is secured at or near the proximal end of the outer tube  18 . 
         [0048]    In use, the outer tube  18  and inner rod  70  move in unison and the inner tube  16  telescopes between them. In a manner similar to the embodiment shown in  FIG. 3 , movement of the inner tube  16  relative to the outer tube  18  generates a transverse load on the friction pad  28  or otherwise compresses the friction pad  28  which increases frictional resistance. In the embodiment shown in  FIG. 6 , the inner rod  70  is tapered at least at one end, such that as the friction pad  28  is drawn along the inner rod  70 , the increasing diameter of the inner rod  70  urges the friction pad  28  radially outwards. 
         [0049]    As further shown in  FIG. 6 , the friction pad  28  is captured between the inner rod  70  and an inner bearing surface  80  of head  40 . As such, as the friction pad  28  is translated along inner rod  70  and driven outwardly, the friction pad  28  is compressed between the inner bearing surface  80  and an outer rod surface  82 . 
         [0050]    To retain the friction pad  28  within the head  40 , in one embodiment, a pad seat  46  includes the inner bearing surface  80 , a seat land  84  and a retaining ring  86 . To retain the head  40  at the proximal end of the inner tube  16 , the head  40  may include a threaded region  90  to mate with a tapped bore  92  disposed in the inner tube  16 . Also shown in  FIG. 6 , the outer tube  18  may include one or more ports  94  to allow for the ingress and/or egress of air. If included, these ports  94  may reduce or prevent the generation of a partial vacuum or pressurized air that may interfere with the operation of the hold open rod  12 . In addition, the ports  94  may facilitate the egress of condensate. 
         [0051]      FIG. 7  is a cross-sectional perspective view of the hold open rod  12  at the distal end of the inner rod  70 . For the sake of clarity, the outer tube  18  has been removed. As shown in  FIG. 7 , the distal end of the inner rod  70  may also be tapered at region  100 . The tapered region  100  may facilitate retaining the hold open rod  12  in an open or extended configuration. At region  110 , the inner rod  70  may be relatively straight sided. In this manner, frictional resistance generated by friction pads  28  may remain relatively constant through some portion of the travel. The tapered region  100  confers several advantages; for example, tapered region  100  facilitates assembly because an outer diameter of the inner rod  70  at the distal end is less than an inner diameter of the friction pads  28 . Another advantage is that initial frictional resistance may be reduced to facilitate ease of closing the door  10  (shown in  FIGS. 1 and 2 ). That is, at a fully extended configuration, the reduced diameter of the inner rod  70  may exert relatively less frictional resistance as compared to the frictional resistance as the hold open rod  12  is retracted. If the frictional resistance is insufficient to hold the door  10  against the bias of the door  10 , the door  10  may continue to close until the bias and the frictional resistance are in equilibrium. From this state of equilibrium, a relatively small amount of closing force will initiate closing the door  10 . Another advantage is that an operational state of the hold open rod  12  may be determined based upon the point in the swing of the door  10  at which the state of equilibrium occurs. For example, if the friction pads  28  loose some thickness due to wear, the state of equilibrium may occur further from the distal end of the inner rod  70 . As such, the state of operation of the hold open rod  12  may be readily determined by personnel without the need of testing equipment. 
         [0052]      FIG. 8  is a cross-sectional view of the hold open rod  12  according to another embodiment of the invention. As shown in  FIG. 8 , the friction pads  28  provides frictional resistance to extension of the hold open rod  12  and relatively less frictional resistance to retraction of the hold open rod  12 . To generate this frictional resistance, the pad seat  46  is frusta-conical; compression of the friction pads  28  occurs during extension of the hold open rod  12 . 
         [0053]      FIG. 9  is a cross-sectional perspective view of the hold open rod  12  depicted in  FIG. 8 . Threaded region  120  mates with tapped bore  122 , thereby facilitating disassembly, servicing or replacing the friction pads  28 , and re-assembly. In this and other embodiments, the head  40  includes retaining ring  64  (shown in  FIG. 7 ), set screw, or the like to facilitate servicing the friction pads  28 . 
         [0054]      FIG. 10  is a perspective view of the friction pad of the hold open rod  12  according to an embodiment of the invention. As shown in  FIG. 10 , friction pads  28  may be a single friction pad. In the embodiment shown in  FIG. 10 , the friction pad  28  may include a slit  128  to accommodate expansion/contraction of the pad seat  46 /inner rod  70 . 
         [0055]      FIG. 11  is an isometric cross-sectional view of the hold open rod  12  according to an embodiment of the invention. Hold open rod  12  includes a release assembly  130  including a release collar  132  and lock body  134 , and a fitting  136  to secure the hold open rod  12  to bracket  22 . In various embodiments, fitting  136 , such as an eye bolt or the like, may be threaded, press fit, or otherwise secured to the adapter  72 . 
         [0056]      FIG. 12  is an isometric cross-sectional view of the release assembly  130  according to the embodiment shown in  FIG. 11 . When disposed in a ‘locked configuration’, the release collar  132  retains one or more locking dogs  140  into a dog groove  142 . The dog groove  142  is disposed about the inner tube  16 . The release collar  132  further includes a release groove  144 . In response to the release collar  132  being in an ‘unlocked configuration’ the release groove  144  is disposed cooperative alignment with the locking dogs  140  to allow the locking dogs  140  to slide out of the dog groove  142 . In this manner, the inner tube  16  is allowed to retract into the outer tube  18 . To bias the release collar  132  in the locked configuration, the release assembly  130  may include a spring  146 . To release the release assembly  130 , the release collar  132  is urged to slide relative to the release body  134  against the bias of the spring  146 . While in the release configuration, the inner tube  16  may be allowed to slide relative to the outer tube  18 . 
         [0057]      FIG. 13  is an isometric cross-sectional view of an end fitting suitable for attachment to a proximal end of the hold open rod  12 . Fitting  136  is secured in the adapter  72 . In various examples, fitting  136  may include any suitable end fitting for attachment to the door  10  or a frame of the door  10 . Examples of suitable end fittings include eye bolts, rod end bearings, universal joints, clevis pins, and the like. Fitting  136  may be secured to the adapter  72  in any suitable manner. For example, fitting  136  may be threaded into a tapped bore, press fit, locked via a set screw, and/or the like. In the particular example shown, the fitting  136  includes a threaded region  150  to mate with a tapped bore  152 . To further secure the fitting  136  in the adapter  72 , a locking nut  154  may be utilized. 
         [0058]      FIG. 14  is an isometric cross-sectional view of an end fitting suitable for attachment to a distal end of the hold open rod  12 . As shown in  FIG. 14 , fitting  160  is secured to the distal end of the inner tube  16 . In various examples, the fitting  160  may include any suitable end fitting for attachment to the door  10  or a frame of the door  10 . Examples of suitable end fittings include eye bolts, rod end bearings, universal joints, clevis pins, and the like. The fitting  160  may be secured to the inner tube  16  in any suitable manner. For example, the fitting  160  may be threaded into a tapped bore, press fit, locked via a set screw, and/or the like. In the particular example shown, the fitting  160  includes a threaded region  162  to mate with a tapped bore  164 . To further secure the fitting  160  in the inner tube  16 , a locking nut  166  may be utilized. 
         [0059]      FIGS. 15 and 16  are perspective views of a hold open rod  200  in accordance with other embodiments of the invention.  FIG. 15  shows a hold open rod  200  in an extended position.  FIG. 16  shows the hold open rod  200  in a retracted position. With reference to both  FIGS. 15 and 16 , the hold open rod  200  has an inner tube  16  and outer tube  18 . A fitting  136  is located on the outer tube  18 . A locking nut  154  helps to secure the fitting  136  to the outer tube  18 . The inner tube  16  also contains a fitting  160 . A locking nut  166  helps to attach the fitting  136  onto the inner tube  16 . The inner tube  16  and outer tube  18  fittings  136 ,  160  and locking nuts  154  and  166  are similar to those described above. One difference between the hold open rod showed in the earlier Figures and the hold open rod  200  of  FIGS. 15 and 16  is that the hold open rod  200  of  FIGS. 15 and 16  include the hold open assembly  202 . 
         [0060]      FIGS. 17 and 18  illustrate a hold open assembly  202  in accordance with another embodiment of the invention.  FIGS. 19 and 20  illustrate a hold open assembly  202  in accordance with yet another embodiment of the invention. The hold open assembly  202  shown in  FIGS. 17 through 20  are similar and will be described in turn. Like reference numerals shown in the embodiment shown in  FIGS. 17 through 20  refer to like or similar parts. 
         [0061]    The embodiment shown in  FIGS. 17 and 18  will now be described. The outer tube  18  has a lock body  204  attached to the outer tube  18 . A release collar  206  covers the lock body  204 . The release collar  206  is movable between a lock position and an unlock position. The position shown in  FIGS. 17 through 20  show the release collar  206  in the lock position. When the release collar  206  is in the lock position the hold open assembly  202  is configured to allow the inner tube  16  to slide within the outer tube  18 . However, the inner tube  16  and the outer tube  18  can not be separated without damaging the inner tube  16 , the outer tube  18  or the hold open assembly  202 . When the release collar  206  is moved axially to an unlock position, the inner tube  16  and outer tube  18  may be easily separated. 
         [0062]    The release collar  206  contains a dog groove  224 . A locking dog  222  sits within the lock body  204  and the dog groove  224 . When the release collar  206  is moved to towards the unlock position, the spring  220  is compressed and the release groove  226  is aligned with the lock dog  222 . The lock dog  222  is then allowed to expand into the release groove  226 , thereby unlocking the inner tube  16  to the outer tube  18  and allowing the two to separate. 
         [0063]    The spring  220  is captured between the release collar  206  and the lock body  204 . The release collar  206  is biased by the spring  220  into the locking position. According to the embodiment shown in  FIGS. 17 and 18 , a retaining ring is used to prevent the release collar  206  from moving into the release position. The retaining ring  218  must be removed or flexed in order to allow the release collar  206  to move to the unlocking position. Other embodiments, such is that shown in  FIGS. 19 and 20 , do not have a retaining ring  218 . 
         [0064]    The lock body  204  and the inner tube  16  trap a dampening pad  210 . the dampening pad  210  may be made of elastomeric material such as ethylene vinyl acetate, for example. Other materials for the dampening pad  210  may be used. According to some embodiments of the invention, one purpose of the dampening pad  210  is to provide friction as the inner tube  16  slides past the outer tube  18  and the lock body  204 . 
         [0065]    In some embodiments of the invention, the outer diameter or outer surface  216  of the inner tube  16  may be tapered so that the friction force created by the adjustable dampening pad  210  increases at selected positions along the inner tube  16 . As shown in  FIGS. 17 and 18 , the lock body  204  may also have a tapered surface  208 . The dampening pad  210  may also have a corresponding tapered surface  211  corresponding to the tapered surface  208  on the lock body  204 . The tapers on the outer surface  216  of the inner tube  16  and the tapered surface  208  on the lock body  204  may be selected to increase the friction between the inner tube  16  and the outer tube  18  and/or lock body  204  as the hold open rod  200  achieves an extended position as shown in  FIG. 15 . In some embodiments of the invention the surfaces  216  and/or  208  maybe be frusta-conical shaped, and, in other embodiments, the surfaces  216  and  208  may be tapered. 
         [0066]    According to some of the embodiments of the invention the amount of frictional force applied by the dampening pad  210  may be adjusted. For example, an adjustor  214  may be threadably attached to the lock body  204 . As shown in  FIGS. 17 and 18  the adjustor  214  is threadably attached to the lock body  204 . The adjustor  214  has a knurled surface  215  as shown in  FIG. 18 , for example, and is turned by a user. By turning the adjustor  214 , the threads on the adjustor  214  interact with corresponding threads on the lock body  204  to move the adjustor  214  along the lock body  204 . Moving the adjustor  214  causes the spacer  212  to move and compress or move the dampening pad  210 . By compressing and moving the dampening pad  210 , the dampening pad  210  will increase the amount of friction force exerted on the outer surface  216  of the inner tube  16  and the surface  208  on the lock body  204 . Therefore, a user may advantageously adjust the amount of friction or resistance the hold open rod  12  has by turning the adjustor  214 . 
         [0067]    The embodiments shown in  FIGS. 19 and 20  are similar to that shown and described above with respect to  FIGS. 17 and 18 , as noted above. For example, as shown in  FIGS. 19 and 20 , an inner tube  16  and outer tube  18  are fit together in a telescoping manner. The outer tube  18  is equipped with a lock body  204 . The lock body  204  and the inner tube  16  trap a dampening pad  228 . The dampening pad  228  maybe made of similar materials as described above with respect to damping pad  210  of  FIGS. 17 and 18 . However, the dampening pad  228  may not have the tapered surface  211  as shown in  FIGS. 17 and 18 . 
         [0068]    The release collar  206  of the embodiments shown in  FIGS. 19 and 20  may not be equipped with the retaining ring  218 . Therefore, the release collar  206  is free to be moved against the urging of the spring  220  to the release position where the locking dog  222  moves from the dog groove  224  to the release groove  226  and expands to fill the release groove  226 . This movement of the locking dog  222  permits the inner tube  16  to be separated from the inner tube  16  and the lock body  204 . As discussed above, in some embodiments the tension or friction exerted by the dampening pad  210  (or  228 ) on the inner tube  16  and the lock body  204  may be adjusted by turning the end cap  230  (or  214 ) which, in turn, moves the spacer  212  to compress the dampening pad  210  (or  220 ), as described above. In other embodiments, the end cap  230  or  214  is not adjustably engaged with the lock body  204 , but rather is fixed in place. In such an arrangement, the end cap  214  or  228  is fixed and can not adjustably import compressive force on the dampening pad  210  (or  228 ). 
         [0069]      FIG. 20  is a close-up partial view of part of the hold open assembly  202 . The inner tube  16  and the lock body  204  are shown entrapping the dampening pad  228 . In some embodiments the inner tube  16  is tapered. The lines  232  illustrate a gap showing an amount of reduction in diameter of the inner tube  16  resulting from the taper along the length of the dampening pad  210 . The amount of the reduction maybe selected to achieve the amount of dampening force desired at various points along the length of the inner tube  16 . 
         [0070]      FIG. 21  is an isometric view of a tapered dampening pad  210 , which has tapered surfaces  211  in accordance with the embodiment shown in  FIGS. 17 and 18 . In one embodiment, the tapered dampening pad  210  may also have relief grooves  234 , which aid in allowing the dampening pad  210  to be compressed. 
         [0071]    The many features and advantages of the invention are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and, accordingly, all suitable modifications and equivalents may be resorted to that fall within the scope of the invention.