Abstract:
A safety device for maintaining a load raised cylinder linkage in selected extended position. A combination cylinder engagement rod and locking sleeve with a piston rod engagement channel that will adjustably secure and extended piston rod from a cylinder assembly in a safe secure locked extended position. The cylinder safety stop of the invention is interposed between the cylinder sleeve and the piston end block by the incrementally adjustable engagement panel&#39;s positioning via removably positioned stop adjustment pin. An intermediate incrementally adjustable fitting provides for positioning between multiple aligned stop pin engagement apertures.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to piston and cylinder stops that secure the piston rod when it is in extended position to prevent accidental deactivation of the piston and cylinder assembly when in extended support linkage load bearing engagement. 
     2. Description of Prior Art 
     Prior art devices of this type have been directed to a variety of cylinder locks that will engage the piston and cylinder and keeping it from retracting unintentionally. See for example U.S. Pat. Nos. 4,043,253, 4,122,758, 4,483,564 and 4,947,705. 
     In U.S. Pat. No. 4,043,253 a boom cylinder stop for lift cylinders is disclosed having a tubular bearing mounted on the rod so that when extended it will drop down and engage the cylinder holding same in place. 
     U.S. Pat. No. 4,122,758 is directed to a service support wherein a U shaped bracket is bolted to an extended lift rod, locking it in place. 
     U.S. Pat. No. 4,483,564 claims an oil well sucker rod safety block formed of a slotted pipe with a handle that is positioned over the well spring and held in place by end caps and engagement of the string thereon. 
     U.S. Pat. No. 4,947,705 discloses a method and apparatus for maintaining a load raising linkage in raised position. The device comprises a locking member pivoted between an unlocked position and a locking position over the extended piston rod. 
     SUMMARY OF THE INVENTION 
     A safety apparatus for engaging and holding a piston rod and cylinder assembly in extended and locked position preventing accidental or unintentional retraction of the piston rod. The device has a cylinder end engagement locking sleeve plate with an intermediate adjustable fitting extending therefrom. An elongated piston rod engagement channel is slidably disposed over the piston rod and has a plurality of longitudinally and transversely aligned apertures formed therein. A stop pin is selectively repositioned through aligned apertured pairs for registration with the cylinder end engagement locking sleeve plate securing the rod engagement channel against the piston rod and block preventing the piston rod from unintentional retraction into the cylinder. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the cylinder stop in engaged and lock extended position. 
         FIG. 2  is a side elevational view of the cylinder stop in engaged piston rod retracted position. 
         FIG. 3  is a front elevational view thereof. 
         FIG. 4  is a front elevational view of a cylinder end engagement locking sleeve fitting. 
         FIG. 5  is a side elevational view of the cylinder end engagement locking sleeve with piston rod engagement channel portion shown in broken lines. 
         FIG. 6  is a top plan view thereof. 
         FIG. 7  is a perspective view of an alternate form of the cylinder stop of the invention in engaged cylinder piston rod position. 
         FIG. 8  is a front elevational view thereof. 
         FIG. 9  is a front elevational view in cylinder extended and locked position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1  of the drawings, the cylinder safety stop  10  of the invention can be seen engaged on a piston and cylinder assembly  11  which has a cylinder body  12  with a piston rod  13  reciprocally positioned therein. The cylinder body  12  extends from and is integral with a cylinder base block  14  having fluid supply attachment portal fittings  15  for connection with a source of fluid under pressure PS as is well known and understood within the art. 
     The piston rod  13  has a piston rod block  16  secured to its free end, having a bore  17  extending transversely therethrough which provides a point of attachment for the cylinder safety stop  10  as will be described in detail hereinafter. 
     The cylinder safety stop  10  of the invention has a cylinder end engagement locking sleeve fitting  18 , best seen in  FIGS. 1 and 3-6  of the drawings. The locking sleeve fitting  18  has a main body member  19  with an integral engagement plate  20  extending from its upper end surface  21 . The engagement plate  20  has an annular opening at  22  sized for allowing the piston rod  13  to pass therethrough when the cylinder end engagement locking sleeve  18  is attached to the free end  12 A of the cylinder body  12 . 
     An adjustment stop bolt  23  is threadably disposed through the engagement plate  20  with a lock nut  24  positioned thereon. The adjustable bolt  23  can be rotatably advanced thereby extending above the plate&#39;s  20  planar upper surface  20 A for adjustable stop engagement as will be described hereinafter. 
     An elongated U-shaped piston rod block engagement channel  25  is slidably positioned on the piston rod  13  of the cylinder assembly  11  having a plurality of longitudinally and transversely aligned apertures A along the respective edges of the channels upstanding sidewalls  26  and  27 , best seen in  FIG. 1  of the drawings. In this primary form of the invention a pair of correspondingly aligned and apertured overlying reinforcement brackets  28  and  29  are secured respectively thereto and extend beyond the respective sidewall ends  26 A and  27 A with angularly offset portions  28 A and  29 A, best seen in  FIGS. 1 and 2  of the drawings. The offset bracket portions  28 A and  29 A provide for end apertured aligned registration with a piston block pin  30  extending from the piston block bore  17  respective openings as hereinbefore described. The transversely aligned wall apertures A also provide for selective insertion of a removable stop lock pin  31  therethrough for in use engagement with the hereinbefore described engagement plate  20 &#39;s upper planar surface  20 A and alternately the adjustment bolt  23  in registerable alignment therewith of the cylinder and engagement locking sleeve  18 . 
     Referring now to  FIGS. 1, 2 and 3  of the drawings, it will be seen that once the cylinder safety stop  10  of the invention has been initially positioned and secured on the piston and cylinder assembly  11  by engagement of the piston block pin  30  through the respective apertured angularly offset portions  28 A and  29 A of the reinforcement brackets  28  and  29  and that the stop lock pin  31  extend through aligned apertures A will initially rest on the engagement plate  20  when the piston rod  13  is in fully retracted (rest) position within the cylinder  12  as seen in  FIGS. 2 and 3  of the drawings. 
     Once installed and in use, upon activation the piston and cylinder assembly  11 , the piston rod  13  will extend pulling the engagement channel  25  therewith to the desired extended rod position as seen in  FIG. 1  of the drawings. The stop lock pin  31  will be repositioned through the appropriate aligned sidewall apertures A and inserted. The stop lock pin  31  will now, therefore, once again engage the upper surface  20 A of the engagement plate  20  preventing the piston rod  13  from retracting, effectively locking the cylinder and piston assembly  11  in a fail safe extended position. 
     It will be seen that the adjustment bolt  23  can be rotatably advanced from within the sleeve plate  20  and secured in place by the locking nut  24  providing for incremental fine extending adjustment to match the actual extended piston rod  13  position if it falls between the hereinbefore described aligned sidewall apertures A assuring incremental locking engagement of the piston rod  13  at any effective extended position. 
     Referring now to  FIGS. 7, 8 and 9  of the drawings, an alternate form of the cylinder safety stop lock of the invention can be seen at  40  wherein a modified elongated U-shaped piston rod lock engagement channel  41  can be seen positioned on a piston and cylinder assembly  42  having a cylinder body  43  and a piston rod  44  with a piston rod end block  45  secured thereto. 
     The cylinder body  43  has a cylinder body block  46  with fluid attachment portal fittings  47  as will be well understood by those skilled in the art for a supply of fluid under pressure indicated graphically at arrow FP. 
     A cylinder end engagement attachment fitting  48  which is identical to that of the hereinbefore described cylinder end engagement locking sleeve fitting  18  with a corresponding engagement plate  50 , fine adjustment bolt  51  and off center opening at  52  for the piston rod  44  to pass therethrough when activated. The elongated U-shaped piston rod engagement channel  41  having spaced parallel apertured sidewalls  53  and  54  has a corresponding stop lock pin  55  removably positioned through the aligned apertured pairs AP extending in longitudinally and spaced aligned rows adjacent the edges of the respectively described sidewalls  53  and  54  as best seen in  FIGS. 1 and 4  of the drawings in non-activated engagement position. 
     It will therefore be evident that the stop lock pin  55  once positioned will registerably engage on the engagement plate  50  and the piston rod and lock engagement channel  41  will abut the bottom surface  45 A of the piston rod end block  43 . This orientation functions as a locking feature can be seen in  FIG. 9  of the drawings wherein the piston rod  44  and its end block  43  have been extended showing the cylinder stop lock  40  registerably secured between the piston rod end block  45  and the cylinder engagement attachment fitting  48  by engagement of the lock stop pin  55  securing the piston rod  44  in a fail safe lock extended fail safe lock position. 
     It will be evident from the above referred to description that while the alternate form of the invention is manually utilized, certain applications would be suitable for same while the primary form of the invention provides a self-deploying system for different applications. 
     It will therefore be seen that a new and novel cylinder safety stop has been illustrated and described providing for multiple forms  10  and  40  for adaptable integrated use. It will be evident to those skilled in the art that various changes and modification may be made thereto without departing from the spirit of the invention.