Abstract:
This invention is directed to a system for actuating manipulator jaws. This system employs a double sided rack, each side of which engages a pinion at a first end of a rotatably mounted lever. The second end of each lever comprises a jaw region. The present invention may be used with subsea manipulators mounted on remotely operated vehicles (“ROV&#39;s”).

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Provisional Application Ser. No. 60/847,625, filed on Sep. 27, 2006. 
     
     FIELD OF THE INVENTION 
       [0002]    This invention is directed to a system for actuating manipulator jaws. This system employs a double sided rack, each side of which engages a pinion at a first end of a rotatably mounted lever. The second end of each lever comprises a jaw region. The present invention may be used with subsea manipulators mounted on remotely operated vehicles (“ROV&#39;s”). 
       BACKGROUND OF THE INVENTION 
       [0003]    Prior art systems for actuating manipulator jaws comprise “C” shaped bushings, herein referred to as a “C bushing” that engages a T plate attached to a reciprocating piston. In such prior systems, as the piston extends, the contact between the C bushings and the t plate is steadily reduced. In such prior art systems, as the manipulator is used and the jaws are clamped around whatever is being pulled, moved, or picked up, this interface between the piston and link arms becomes the weak point of the assembly. 
         [0004]    In prior art systems comprising C bushings and a T plate, the force of an uneven load on the jaws can cause the T-plate to be pried away from the piston shaft, causing the bolt that secures it to bend, thereby causing the C-bushings to become bound up on the T-plate. This can result in jamming of the jaws after several actuations. This can eventually lead to damage to the C bushings, the T plate and/or the associated bolt. 
         [0005]    In the rack and pinion design used in preferred embodiments of this invention, the same forces are applied substantially evenly throughout the range of motion of the link arms and piston. Also, if the link arms are loaded unevenly because of shifted or heavy load, the force is transferred thru the link arm pinion pivot pin, the rack, and the other link arm pinion pivot pin. This is a preferable load distribution to that of the prior art systems described above. 
     
     
       DESCRIPTION OF THE DRAWINGS 
         [0006]      FIGS. 1   a - 1   b  are a side views of one preferred apparatus embodiment of the invention with the jaws closed and opened, respectively. 
           [0007]      FIG. 2  is a side cross sectional view of a preferred embodiment of the piston housing and piston suitable for use in practicing the present invention. 
           [0008]      FIG. 3  is a side view of a another preferred embodiment of the piston housing and piston used in the invention. 
           [0009]      FIG. 4  is an isometric view of another apparatus embodiment of the invention. 
           [0010]      FIG. 5  is an exploded isometric view of another apparatus embodiment of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0011]    A first preferred apparatus embodiment of the invention is directed to a manipulator jaw and actuator system. It comprises a piston housing  10  comprising a piston chamber  12 , a fluid inlet  14 , and a fluid outlet  16 , as shown in  FIG. 2 . In one preferred embodiment, the piston housing is cylindrical. 
         [0012]    This apparatus embodiment further comprises a piston  18  having a lower region  20  slideably mounted in the piston chamber and an upper region  22  extending beyond the piston housing, as shown in  FIG. 2 , The piston is mounted in the housing such that the piston can reciprocate longitudinally from a final extended position, as shown in  FIG. 1   b,  to a final retracted position, as shown in  FIG. 1   a,  and from a final retracted position to a final extended position. The directions of this longitudinal reciprocation is denoted by arrow Z in  FIG. 2 . 
         [0013]    This apparatus embodiment further comprises a toothed rack  24  mounted on the upper region of said piston such that the rack moves with the piston, as shown in  FIGS. 1   a - 1   b . The rack has a first side  26  comprising three toothed fingers  27   a - 27   c  facing in a first direction, as shown in  FIGS. 1   a - 1   b,  and  5 . The rack has a second side  28  comprising three toothed fingers  29   a - 29   c  facing in a second direction opposite to the first direction, as shown in  FIGS. 1   a - 1   b,  and  5 . 
         [0014]    This apparatus embodiment further comprises a first lever  30  comprising a first upper jaw  32  region and a first lower region  34  pivotally connected to the piston housing, as shown in  FIGS. 1   a - 1   b,  and  5 . The first lower region comprises a first pinion  36  having at least three toothed fingers  37   a - c  positioned to rotatably engage the first side of the toothed rack such that the first upper jaw region swings outward when the piston moves from a final retracted to a final extended position and swings inward when the piston moves from a final extended to a final retracted position, as shown in  FIGS. 1   a - 1   b,  and  5 . 
         [0015]    This apparatus embodiment further comprises a second lever  40  comprising a second upper jaw  42  region and a second lower region  44  pivotally connected to the piston housing, as shown in  FIGS. 1   a - 1   b,  and  5 . The second lower region comprises a second pinion  46  having at least three toothed fingers  47   a - c  positioned to rotatably engage the second side of the toothed rack such that the second upper jaw region swings outward when the piston moves from a final retracted to a final extended position and swings inward when the piston moves from a final extended to a final retracted position, as shown in  FIGS. 1   a - 1   b,  and  5 . 
         [0016]    In the preferred embodiment shown in  FIGS. 1   a - 1   b,  the first and second upper jaws are toothed. 
         [0017]    In another preferred embodiment, the first and second sides of the rack comprise two toothed fingers and the lower regions of the first and second levers each comprise two toothed fingers. 
         [0018]    In another preferred apparatus embodiment, the rack is split down the middle into two components. The first component contains the first side of the rack described above and the second component contains the second side of the rack described above. 
         [0019]    In another preferred embodiment, each jaw region comprises multiple toothed fingers, as shown in  FIG. 4 . In the preferred embodiment shown in  FIG. 4 , the multiple toothed fingers are curved. 
         [0020]    In another preferred embodiment, the invention further comprises a manipulator arm attached to the piston housing. In a preferred embodiment, the manipulator arm is articulated. In another preferred embodiment, the invention comprises a remotely operated vehicle attached to the manipulator arm. In a preferred embodiment, the remotely operated vehicle comprises a hydraulic fluid reservoir and pumping system to control the position of the manipulator arm and piston. 
         [0021]    It will be understood that various changes in size, shape, detail, parameters, and arrangements of the embodiments which have been described and illustrated above in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the invention.