Abstract:
Hydraulic spring drive apparatus comprising: a rotatable cam shaft having fixed thereon a number of cams; a number of rocker arms, one following each cam, each pivotally attached at one end to a pressure bar and at another to an expansible, compressible connecting means in turn connected to a crank portion of a crank shaft. The cams, crank shaft, and expansible compressible connecting means are arranged so that a number of connecting means expand against the compression of one connecting means. The pressure bar is movable to position the rocker arms for a selected degree of connecting means compression.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Application No. 60/899,924 filed on Feb. 6, 2007, the contents of which are incorporated herein fully by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is related to the field of motors and more specifically, a hydraulically driven spring drive motor. 
       SUMMARY OF THE INVENTION 
       [0003]    According to the present invention, a hydraulic spring drive apparatus is provided whereby independent spring force for rotation is continuously delivered by a number of expansible, compressible connecting means operating so that at any given time, more connecting means are expanding than are being compressed. 
         [0004]    As embodied in a presently preferred apparatus, a rotatable cam shaft has axially spaced along its length a number of cams fixed to the shaft for rotation therewith. Each cam has an edge varying in distance from a center of rotation of the cam between a maximum distance and minimum distance. A number of rocker arms, one following each cam, are pivotally attached, in a predetermined position, to the apparatus at one end and support at an opposite end expansible, compressible connecting means. A crank shaft having an eccentric crank portion for connection with each connecting means is rotatably driven by rotation of the cam shaft and reciprocal movement of the connecting means. Each cam is shaped so that the maximum distance at its edge extends through a minor portion (about 90°) of its 360° rotation and the minimum distance extends through a larger portion (about 135°) of rotation with a sharp rise from minimum to maximum distance and a gradual decline from maximum to minimum distance as the cam rotates. The arrangement at the edge of the cams provides compression of one connecting means opposed to expansion of a plurality of other connecting means. A hydraulic pump may be connected to the cam shaft for rotation with the cam shaft to aid in the operation of a throttle system. The throttle system may be used to control the rest position of the rocker arms by displacing a pressure bar connected to a rocker arm riding on each cam. Adjustment of the rocker arm controls the degree of compression and expansion of each connecting means. 
     
    
     
       DESCRIPTION OF THE DRAWING 
         [0005]      FIG. 1  is a side sectional view of an apparatus of the present invention with portions removed for clarity. 
           [0006]      FIG. 2  is an end view of the apparatus of  FIG. 1 , with portions removed for clarity. 
           [0007]      FIG. 3  is a section view of the power unit assembly shown in  FIG. 2 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0008]    Referring now to  FIGS. 1 and 2 , the present apparatus is contained in a rectangular housing  4  which supports a crank shaft  6 , a cam shaft  8 , and a rocker arm assembly  10 . A hydraulic pump  12  and throttle assembly  14  are mounted on the housing. 
         [0009]    The crank shaft  6  is mounted axially through an upper portion of the housing  4  through forward bearing  16  and rearward bearing  18  and comprises equally axially spaced eccentric crank portions  20  for each cam and connecting means, there being eight in the presently preferred embodiment. Each crank portion  20  comprises a pair of axially offset members and a cross piece  22  which rotates in a circle of a given diameter Dcr about the axis of rotation  24  of the crank shaft. 
         [0010]    The cam shaft  8  is supported on a forward bearing  26  and a rearward bearing  28  and supports eight cams  30  in equally axially spaced relationship along its length, one opposite each crank portion  20 . The cam shaft terminates forwardly in a pulley wheel  32  and rearwardly in a flywheel  34 . The cam shaft may be journaled to support engagement with the plurality of cams for rotation therewith. 
         [0011]    The cams  30  are mounted in circumferentially offset relationship to each other so that each succeeding cam is offset from its rearwardly adjacent cam by 360° divided by the number of cams, or 45°. Similarly, each crank portion  20  is offset from its rearwardly adjacent crank portion by 45° so that, as shown in  FIG. 2 , a cam denominated  180  will be oppositely connected to a crank portion having its 180 portion engaging a rocker arm. A cam advanced 45° in the direction of arrow  36  is oppositely connected to a crank portion  225 , and so forth. A timing gear  38  engages gears  40 ,  42  on the crank shaft and cam shaft, respectively, to maintain the cams and crank portion in the above-described predetermined relationship. 
         [0012]    Each cam  30  is of the same modified disk shape having modified edge surface  41  as shown in  FIG. 2 . Each cam may be divided into eight sectors,  0 - 360 . The edge surface of sectors comprising angles  135 - 225  are at a minimum distance from the axis  44  of rotation of the cams. Sectors  270  and  225  comprises a rate of 90° and the edge  41  of cam  30 , is curved slightly outwardly. From 270° the edge continues at a maximum distance from axis to sector  0 , along which it describes a circle of a diameter approximately Dcr, From sector  0 , the cam gradually returns to a minimum distance in the vicinity of sector  90 . 
         [0013]    With reference to  FIG. 2 , the rocker arm assembly  10  comprises an axially elongated pressure bar  46  supported through three axially spaced, upwardly extending rod portions  48 - 52  ( FIG. 2 ). The rod portions  48 ,  50 ,  52  are slidably fitted into tube portions  49 ,  51 ,  53  in the housing  4 . Eight rocker arms  54  are pivotally connected to the pressure bar  46  to extend generally horizontally laterally to move in parallel pivotal directions as shown by arrow  56 . Each rocker arm  54  moves in cooperation with a earn  30  operational engaged with the cam, and are connected to a power rod assembly  58 . Each rocker arm  54  is of the same shape and may comprise a lower surface having a curved projection  60  which rides on the cam  30  and follows the cam through the edge variations described above. The outward portion  61  of the rocker arm is curved slightly downwardly so that the power rod assembly  58  joins the rocker arm at a portion thereof which is downwardly offset from the projection  60 . A cavity portion  62  extends through the outward portion  61  of the rocker arm  54  to slidably receive a shaft  64  of the power rod assembly  58 . A pin  66  pivotally supports and drivably engages a spring cup pivot  68  of the power rod assembly. 
         [0014]    The power rod assembly  58  transmits reciprocal movement of its associated rocker arm  54  to a corresponding crank portion  22  ( FIG. 1 ) of the crank shaft  20  and supplements this motion through expansion of a spring member  72 . 
         [0015]    Turning to  FIG. 3 , each power unit assembly  58  comprises an upper nose piece  70 , a coil spring  72 , the shaft  64 , and a spring cup pivot  68 . The upper nose piece  70  is rotatably fixed to its associated cross piece  22  on the crank shaft  20  and terminates downwardly in rim portion comprising a spring receiving aperture  69  and tow connecting rod apertures  71  to receive connecting rods  73 . The coil spring  72  surrounds the shaft  64  and downwardly engages the spring cup  68 . The shaft  64  is fixed to the nose piece  70  and extends to the spring cup  68  supported on the rocker arm  54 . The spring cup  68  is pivotally supported on an upper surface of the rocker arm  54  and comprises an aperture to receive a lower coil of the coil spring  72 . The power unit assembly  58  thus provides compressible, expansible connecting means translating the reciprocal pivotal movement of the rocker arm  54  brought about by the cam  30  into rotation of the crank shaft  20  accompanied by compression and expansion of the coil  72 . Compression and expansion of the coil spring  72  takes place as the spring cup  68  rides on the rocker arm  54  and slides along the shaft  64  towards the nose piece  70 . 
         [0016]    The relationship between the various crank portions, cams, and springs is shown in the following table: 
         [0000]                                                                                  Connecting           Crank           Unit       Composition   Shaft   Cam   Spring Tension   Number                                0   Farthest   Maximum   Idle   1       180   Farthest   Intermediate   Idle   2       270   Closest   0   Compressed   3       90   Farthest   0   Idle   4       315   Closest   Minimum   506 Compressed   5       135   Farthest   Intermediate   Idle   6       45   0   Maximum   Idle   7       225   0   0   50% Compressed   8                    
The above crank shaft positions are those which each individual crank portion goes through during a complete revolution and also those of each member at a given moment.
 
         [0017]    Returning to  FIG. 1 , the hydraulic a pump  12  is used to assist the throttle assembly  14 . The throttle assembly  14  comprises two hydraulic fluid reservoirs, a power assist reservoir  80  and a master reservoir  82 . The master reservoir  82  is the main reservoir and controls the amount of hydraulic pressure from pump  78  delivered through lines  84  to the tube portions  49 ,  51  and  53  of the rocker arm assembly  58 . A source of electric energy  74  controlled by a switch  76  drives an electric pump  78  which develops pressure in the master reservoir  82 . Pressure in the tube portions  49 ,  51  and  53  forces the rocker arm rods  48 ,  50  and  52  downward, pivoting the rest position of the rocker arms toward the crank shaft  20 . Springs  86  in each tube  49 ,  51  and  53  help to force the rods  48 ,  50  and  52  downward to a rest position. Pressure in the tubes  49 ,  51  and  53  is increased through a sliding piston  87  in the master reservoir  82 . The force from the pump  78  initiates and facilitates movement of the piston  87  to decrease reservoir area and increase pressure in the tubes  49 ,  51  and  53 . The piston  87  is reciprocally movable through a shaft  88  connected to a second piston  90  in the power assist reservoir  80 . The second piston  90  also moves forward to displace the first piston  87  to increase pressure in the tubes  49 ,  51  and  53 . Pressure from the hydraulic pump  12  is delivered through lines  92 ,  94  to a first chamber portion  96  of the power assist reservoir  80  and a second chamber portion  98 , containing the piston  90 , of the power assist reservoir. Flow through the first chamber portion is controlled by a sliding plate  102 . The sliding plate  102  is connected to a piston  104  in the first chamber portion  96  and controlled by a rod  106 . Movement of rod  106  increases pressurized fluid flow to the second chamber portion  98  to move the piston  90  forward. The pump  12  is driven by a belt  108  from the cam shaft  8  so that increased motor rpm provides increased pressure for moving the pressure bar. The amount of this pressure delivered to the piston  90  is controlled by the plate  102 . For maximum power output from the present apparatus, increased pressure is delivered to the pressure bas as cam shaft rpm increases. This pressure may be throttled back by movement of the plate  104  to cut off pressure to the piston  90 . 
         [0018]    The present apparatus may further comprise an oiling system. An oil hose  112  is connected to each one of the connecting shafts  64 . Each shaft  64  has an oil channel running through the center of the shaft full length to two holes  114 ,  116 , at the top of the nose piece  70 . The hose  112  which is attached to the end of the connecting shaft  64  is also connected to a main oil line that is connected to an oil pump  118  driven by the cam shaft  8  through the use of a gear. 
         [0019]    When oil is pumped up through the connecting shaft it oils bearings on each one of the crank shaft throws. It also oils and keeps the coil springs from getting hot and losing their tension. This is done by forcing the oil out through the two oil holes  114 ,  116  at the top of the nose piece  70  into a reservoir. This reservoir is created by the uses of a rubber shelf in the nose piece  70  that is clipped to the nose piece of the connecting rod and also clipped to a conventional spring cup and by forming a reservoir. 
         [0020]    The rubber shelf has holes in it about ⅔ of the way up from the bottom of the shelf, allowing the oil to be forced out when the coil spring is being compressed and by doing this it stops the rubber shelf from ballooning. On the power stroke the cooled oil is forced back into the reservoir because the coil spring is being expanded allowing the oil to fill up the reservoir and cooling off the coil spring. The main bearings are oiled similarly. There are oil ports drilled in each one of the supports and an oil hose is connected to each one. 
         [0021]    Various modifications can be made in the design and operation of the present invention without departing from the spirit thereof. Thus, while the principal preferred construction and modes of operation of the invention have been explained in what is now considered to represent its best embodiments, which have been illustrated and described, it should be understood that the invention may be practiced otherwise than as specifically illustrated and described.