Abstract:
A lateral control rod for use in a vehicle cab suspension wherein the control rod has an attenuation assembly imposed therein between the ends thereof which reduces the transmission of vibration and shock therethrough.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a lateral control rod and more particularly to a lateral control rod for use in a cab suspension system. More particularly, the lateral control rod of this invention includes an attenuation assembly imposed therein intermediate the length thereof which reduces the transmission of vibration and shock through the lateral control rod and which also yieldably centers the cab into its neutral position. 
   2. Description of the Related Art 
   Many vehicle cab suspensions have been previously provided for supporting a vehicle cab on the chassis of the vehicle whereby a cushioning or shock absorber effect is achieved to provide a more comfortable ride for the occupant or occupants of the cab. For example, see U.S. Pat. No. 6,540,038 wherein a vehicle cab suspension system is disclosed including a pair of airbags or air springs which are positioned between the rear of the cab and truck frame with the airbags being inflatably adjustable to exert an upward force against the underside of the cab. Cab suspensions have also been developed which include cab springs and dampers located between the vehicle frame and the operator&#39;s cab to minimize transmission of shock and vibration to the cab. Several types of cab suspensions have utilized a lateral control rod or lateral shock absorbers to control lateral movement of the cab with respect to the frame. For example, see U.S. Pat. No. 6,758,294. Although the devices of the prior art have met with some success, it is believed that devices such as that disclosed in U.S. Pat. No. 6,758,294 do not provide the necessary lateral control while minimizing the transmission of vibration and shock from the vehicle frame into the operator&#39;s cab. 
   SUMMARY OF THE INVENTION 
   A lateral control rod is provided for use in a vehicle cab suspension system with the vehicle including a frame and a cab having a rear end which is movably mounted with respect to the frame. The lateral control rod of this invention includes an elongated tube having first and second ends with the first end of the tube being adapted to be pivotally secured to one of the frame or the cab at the rear end thereof. The lateral control rod of this invention also includes an elongated rod having first and second ends with the first end of the rod being adapted to be pivotally secured to the other of the frame or the cab at the rear end thereof. The second end of the rod is longitudinally movably received by the second end of the tube. An attenuation assembly is positioned between the tube and the second rod to reduce the transmission of vibration and shock through the lateral control rod and which also yieldably centers the cab into its neutral position. The attenuation assembly of this invention comprises first and second opposing resilient members such as rubber or elastomeric type members, plastic or metal springs, etc. The resilient members are enclosed within an elongated housing or tube having first and second ends. The first end of the housing is fixed to the second end of the tube with the second end of the housing slidably receiving the second end of the rod. A compression plate is secured to the rod and is positioned within the housing. The first resilient member is positioned between the compression plate and the first end of the housing. The second resilient member is positioned between the compression plate and the second end of the housing. When the rod is slidably moved towards the tube, the second resilient member is compressed. When the rod is slidably moved away from the tube, the first resilient member is compressed. The opposing resilient members not only attenuate (lessen) the transmission of vibration and shock through the control rod, but also yieldably urge the cab into its neutral position. 
   It is therefore a principal object of the invention to provide an improved lateral control rod for use in a vehicle cab suspension system. 
   Yet another object of the invention is to provide a lateral control rod which includes an attenuation assembly associated therewith which reduces shock or vibration transmitted therethrough. 
   Yet another object of the invention is to provide an improved lateral control rod including an attenuation assembly provided thereon which is economical of manufacture, durable in use and refined in appearance. 
   These and other objects will be apparent to those skilled in the art. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a rear view of a typical prior art vehicle cab suspension system which has the lateral control rod of this invention associated therewith; 
       FIG. 2  is an elevational view of the lateral control rod of this invention; 
       FIG. 3  is a sectional view of the dampener assembly of the lateral control rod of this invention; and 
       FIG. 4  is an exploded perspective view of the lateral control rod of this invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION  
   The lateral control rod of this invention is referred to generally by the reference numeral  10  and is designed to be used in cab suspension systems such as disclosed in U.S. Pat. No. 6,758,294 and as partially depicted in  FIG. 1 . In the &#39;294 patent, a pan hard rod 30 is provided to resist or control lateral movement of the cab with respect to the frame. The instant invention is designed to replace such lateral control rods as well as other types of lateral control rods. 
   Lateral control rod  10  includes an elongated tube  12  having a first end  14  and a second end  16 . A transversely disposed collar  18  is secured to end  14  of tube  12  and has a bushing  20  positioned therein in conventional fashion. The collar  18  and bushing  20  may be secured to either the rear of the vehicle cab C or to cross-member CM of the vehicle frame F although collar  18  and bushing  20  will normally be secured to the cab. The numeral  22  refers to a tubular housing having a first end  24  and a second end  26 . The numeral  28  refers to an end cap having a central bore or opening  29  formed therein which receives the second end  16  of tube  12  with the end cap  28  being welded to tube  12 . End cap  28  closes the end  24  of housing  22  and is secured to housing  22  by welding, press-fitting, crimping or the like. 
   Housing  22  has a larger diameter than tube  12  and extends therefrom in a parallel relationship thereto, as seen in the drawings. A plastic or metal bearing or bushing  30  is received in the central opening or bore  29  of end cap  28  and is preferably press-fitted thereinto. 
   Lateral control rod  10  also includes an elongated rod  32  having a first end  34  and a second end  36 . Transversely extending collar  38  is secured to end  34  of rod  32  and has a resilient bushing  40  positioned therein. Collar  38  and bushing  40  are secured to either the vehicle cab or the vehicle frame although collar  38  and bushing  40  will normally be connected to the vehicle frame if collar  18  and bushing  20  are connected to the vehicle cab. Rod  32  is provided with spaced-apart annular grooves  42  and  44  formed in the exterior surface thereof which are adapted to receive snap rings  46  and  48  therein, respectively. 
   Lateral control rod  10  also includes a compression plate  50  having a central bore  52  formed therein. Plate  50  is positioned on rod  32  between annular grooves  42  and  44  and is maintained thereon by the snap rings  46  and  48  positioned at the opposite sides thereof. A resilient member  54  comprised of rubber, elastomer, etc., has a central bore  56  which receives rod  32  and which is positioned at one side of compression plate  50 . Member  54  is generally cylindrical in shape but which preferably has an enlarged diameter portion  58  at its center length. A resilient member  60  comprised of rubber, elastomer, etc., has a central bore  62  which receives rod  32  and which is positioned at the other side of compression plate  50 . Resilient member  60  is identical to resilient member  54  and has an enlarged diameter position  61  at its center length. Although resilient members  54  and  60  will be identical and will have identical spring rates, one of the resilient members may have a greater spring rate than the other resilient member to offer more resistance in one direction. The resilient members  54  and  56  may be replaced by metal or plastic springs if so desired although it is preferred that rubber or elastomeric type members such as shown be utilized. 
   Lateral control rod  10  also includes an end cap  64  having a central bore  66  formed therein which has a plastic or metal bearing or bushing  68  received therein. Bushings  68  and  30  movably receive rod  32 , as seen in  FIG. 3 . End cap  64  closes end  26  of housing  22  and is secured thereto by welding, press-fitting, crimping, etc. 
   When rod  32  is moved towards tube  12 , with the cab in its neutral position, resilient member  54  is compressed between compression plate  50  and end cap  28 . When rod  32  is moved away from tube  12 , with the cab in its neutral position, resilient member  60  is compressed between compression plate  50  and end cap  64 . The resilient members  58  and  60  function as a two-way attenuation assembly imposed between rod  32  and tube  12  which reduces shock forces and vibrations being transmitted from the vehicle frame to the vehicle cab. The lateral control rod is readily adaptable to be installed in new cab suspension systems but also may replace a lateral control rod in existing systems with a minimum amount of time and labor being required. 
   Thus it can be seen that the invention accomplishes at least all of its stated objectives.