Locking mechanism for jack with elevated platform

Abstract

A locking mechanism for an elevatable lift platform, having a work platform, a scissor-jack and a locking mechanism, is utilized to elevate a chassis for straightening or other repairs. The scissor-jack is contracted by a power actuator, thereby increasing the scissor-jacks' vertical height and elevating the platform. The locking mechanism is comprised of a herringbone lock arm and a lock actuator assembly. The lock assembly is positioned on the power actuator and comprises a two locks, a pneumatic cylinder for extending and contracting the locks vertically, and a lock retainer bar for restricting the extension of the locks. The locks incrementally move along the lock arm horizontally as the jacks are contracted or extended. The locks engage grooves located between teeth on the lock arm that prevent the jacks from contracting or expanding. The locks can disengage the grooves if the pneumatic cylinder is activated to release the locks.

What is claimed is:  
     
         1 . A locking mechanism for a jack comprising: 
 a lock arm;    a lock actuator assembly, comprising: 
 a lock actuator cylinder;  
 at least one lock connected to the lock cylinder; and  
 at least one lock retainer bar connected to the lock.  
   
     
     
         2 . The locking mechanism according to  claim 1  wherein the lock arm further comprises an elongated body with at least one row of teeth extending from the outer perimeter of the lock arm.  
     
     
         3 . The locking mechanism according to  claim 2  wherein the backside of each tooth on the lock arm forms approximately a 90° angle with the lock arm and the front side of each tooth slopes at approximately a 45° angle to the lock arm.  
     
     
         4 . The locking mechanism according to  claim 3  wherein the lock arm is a herringbone lock arm with two rows of substantially equally spaced teeth on the upper and lower perimeter, each tooth on the upper perimeter aligned with a tooth on the lower perimeter.  
     
     
         5 . The locking mechanism according to  claim 4 , wherein the lock arm further comprises an aperture in one end of the lock arm for connecting the lock arm to the scissor-jack by a pivot rod.  
     
     
         6 . The locking mechanism according to  claim 5 , wherein the lock arm further comprises an elongated aperture for connecting the lock arm to the jack.  
     
     
         7 . The locking mechanism according to  claim 1 , wherein the lock actuator assembly further comprises at least one spring extending between the locks.  
     
     
         8 . The locking mechanism according to  claim 6 , wherein the lock further comprises a projection for engaging the lock arm.  
     
     
         9 . The locking mechanism according to  claim 7 , wherein the lock further comprises at least two slots for connecting the lock to the lock bar retainer.  
     
     
         10 . The locking mechanism according to  claim 8 , wherein the lock further comprises a recessed center for receiving the pneumatic cylinder.  
     
     
         11 . The locking mechanism according to  claim 9 , wherein the lock further comprises at least one aperture for connecting the pneumatic cylinder to the lock.  
     
     
         12 . The locking mechanism according to  claim 10 , wherein the lock further comprises at least one aperture for connecting the spring to the lock.  
     
     
         13 . A jack comprising: 
 a scissor-type jack;    a power actuator for contracting and expanding the scissor-jack;    a locking mechanism for securing the jack in position;    at least one lock arm; and    a lock actuator assembly, including: 
 a lock for engaging the lock arm including a plurality of teeth; and  
 a pneumatic cylinder for operating the lock.  
   
     
     
         14 . The jack according to  claim 13 , wherein the lock actuator assembly is positioned on the power actuator.  
     
     
         15 . The jack according to  claim 14 , wherein the lock actuator assembly further comprises two locks and a spring extending between the two locks, operable to bias the locks towards each other in an engaged position relative to the teeth of the lock arm.  
     
     
         16 . The jack according to  claim 13 , wherein the lock arm comprises two rows of teeth projecting out from the perimeter of the lock arm.  
     
     
         17 . The jack according to  claim 13 , wherein the lock comprises at least one projection shaped to fit between the teeth of the lock arm.  
     
     
         18 . A straightening bench for selectively elevating a chassis, said bench comprising: 
 a platform;    a plurality of jacks for elevating the platform;    a power actuator for extending the jacks;    a locking mechanism for selectively securing the jacks;    a lock arm including a plurality of teeth extending from the perimeter of the lock arm; and    a lock actuator assembly, comprising: 
 at least one lock connected to the pneumatic cylinder operable to selectively engage the teeth of the lock arm; and  
 a pneumatic cylinder operable to move the lock between engaged and disengaged positions relative to the lock arm teeth.  
   
     
     
         19 . The bench according to  claim 18 , wherein the lock arm further comprises a plurality of teeth equally spaced along the upper and lower perimeter of the lock arm, each upper tooth spaced symmetrically with a lower tooth.  
     
     
         20 . The bench according to  claim 18 , wherein the lock further comprises at least one projection shaped to fit between the teeth of the lock arm.  
     
     
         21 . A locking mechanism for a jack for raising and lowering a vehicle straightening bench, the mechanism comprising: 
 a lock arm including a plurality of teeth;    a lock actuator assembly, including: 
 a lock operable to selectively engage the teeth; and  
 a lock actuator operable to move the lock between engaged and disengaged positions relative to the teeth.  
   
     
     
         22 . The mechanism according to  claim 21 , wherein the teeth comprise a top row of teeth and a bottom row of teeth, the lock actuator assembly further includes a bottom lock, the lock comprises a top lock, and the lock actuator is operable to move the top and bottom lock between the engaged and disengaged positions relative to the top and bottom rows of teeth.  
     
     
         23 . The mechanism according to  claim 22  wherein the lock actuator assembly further includes a biasing member biasing the top and bottom locks toward each other into the engaged position.  
     
     
         24 . The mechanism according to  claim 22  wherein the lock actuator is positioned between the top and bottom locks and is operable to move the locks forward away from each other into the disengaged position.  
     
     
         25 . The mechanism according to  claim 21  wherein the lock arm includes an aperture for attachment to a first pivot point of the jack and an elongated aperture for slidably receiving a second pivot point of the jack.