Abstract:
A hand operated hydraulic press pliers tool is provided comprising an upper stationary handle having a fixed serrated upper jaw portion forming the front end of the stationary handle and a tubular portion forming the rear end of the stationary handle. A serrated lower jaw is pivotally attached to the stationary handle and disposed opposing the upper jaw portion. A hydraulic cylinder assembly is centrally disposed within the upper stationary handle and pivotally attached at one end within the tubular portion of the upper stationary handle near the rear of the handle, and the front end of the cylinder assembly pivotally attached to the lower serrated jaw between the lower jaw pivot handle attachment point and the serrated portion of the jaw. A lower tool handle is pivotally attached to the cylinder assembly yoke that is the front end of the pump assembly. A pivotally attached lower tool handle provides a pump lever disposed to engage a concentrically disposed hydraulic pump assembly within the cylinder assembly wherein depressing the top of the hydraulic pump assembly forces fluid into the cylinder assembly expanding the length of the cylinder assembly when the handles are squeezed together by a user. The longitudinal expansion pivots the lower serrated jaw towards the upper serrated jaw gripping a work piece disposed by a user between the jaws. Repeated cycles of squeezing and releasing the handles of the tool effectuate an incremental closure of the jaws onto a work piece with increasing pressure with each squeezing cycle.

Description:
RELATED APPLICATIONS 
       [0001]    This non-provisional utility patent application, filed in the United States Patent and Trademark Office, claims the benefit of U.S. Provisional Patent Application Ser. No. 61/767,675 filed Feb. 21, 2013 which is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the field of press pliers hand tools. More particularly, this invention is directed to a hydraulically assisted press pliers hand tool. 
       BACKGROUND OF THE INVENTION 
       [0003]    Utilizing a hand tool to apply pressure to a work piece is typically limited by the mechanical advantage provided by the tool and the hand strength of a user. Application of higher pressures typically requires assistance of a hydraulic pump and cylinder mechanism requiring mechanisms that either render the tool too bulky to considered a hand tool or too complex and expensive for causal use. Further hydraulically assisted systems can exhibit reliability issues and typically require routine maintenance. What is needed is a simple hydraulic hand tool capable of providing high pressure to a work piece while being simple to use, reliable, simple to manufacture, low cost and easy to maintain. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    Accordingly, it is an object of the present invention to provide a new type of press pliers hand tool having high reliability, simplicity, low maintenance, low complexity, ease of use and low cost thereby overcoming the various disadvantages of the prior art. 
         [0005]    A hand operated hydraulic press pliers tool is provided comprising an upper stationary handle having a fixed serrated upper jaw portion forming the front end of the stationary handle and a tubular portion forming the rear end of the stationary handle. A lower serrated jaw is pivotally attached to the upper stationary handle and disposed opposing the upper jaw. A hydraulic cylinder assembly, having a front and rear end, is further centrally disposed within the tubular portion of the upper stationary handle with the cylinder assembly rear end pivotally attached within the tubular portion of the upper stationary handle near the rear of the handle, and the front end of the cylinder assembly pivotally attached to the lower serrated jaw between the lower jaw pivot handle attachment point and the serrated portion of the jaw. A lower tool handle, having a proximate and distal end, is pivotally attached, at the lower tool handle proximate end, to the cylinder assembly yoke, the yoke being the front end of the cylinder assembly. The lower tool handle further provides a handle pump lever disposed to engage the top of the hydraulic pump assembly wherein depressing the top of the pump assembly forces fluid into the hydraulic cylinder assembly thereby expanding the length of the cylinder assembly when the lower moving handle and the upper stationery handle are squeezed together by a user. The longitudinal expansion of the cylinder assembly pivots the lower serrated jaw towards the upper serrated jaw gripping a work piece disposed by a user between the jaws. When the lower moving handle is retracted, valves within the pump assembly retain hydraulic fluid within the hydraulic cylinder assembly and the extended length and pressure is maintained, additional hydraulic fluid is drawn into the pump assembly on this back stroke and the cylinder assembly again extends in longitudinal length and internal pressure increases on the next forward stroke. Repeated cycles of squeezing and releasing the handles of the tool effectuate an incremental closure of the jaws onto a work piece with increasing pressure with each squeezing cycle. 
         [0006]    Releasing the press pliers from a work piece requires a user to activate a release handle being pivotally attached to the lower moving handle and having a release lever cam disposed to engage a release collar disposed around the circumference of the pump piston assembly centrally disposed within the tool piston portion of the hydraulic cylinder assembly. The distal end of the pump piston has a push pin centrally disposed to engage the pump outlet check valve that maintains the pressure within the hydraulic cylinder assembly, forcing the valve open and relieving hydraulic fluid out of the hydraulic cylinder assembly and ultimately back to a hydraulic fluid reservoir ready for being drawn back into the hydraulic pump assembly when the tool next engages a work piece. 
         [0007]    Preloaded check valve springs, all centrally and longitudinally disposed, are provided to insure that a user cannot over pressure the hydraulic fluid of tool or damage the tool, principally through repeatedly squeezing the handles of the tool with the jaws clenched, by venting hydraulic fluid back to the reservoir or preventing the uptake of fluid into the pump. When preset pressures are attained, the pump assembly will not extend further in length or increase applied pressure between the jaws. 
         [0008]    The elements of the pump assembly are longitudinally disposed within each other making manufacturing and assembly simple and low cost. The elements are also arranged to minimize the total number of components wherein single elements provide combined functions required by hydraulic pumping systems having lower mechanical tolerances and lower cost material types than typically required thus providing further lower cost advantages, reliability and a compact, light weight design necessary for hand tools. The hydraulic assist facilitates application of pressure to a work piece much higher than obtainable with similar sized mechanical hand tools. 
         [0009]    What is needed is a new type of hydraulic cylinder and pump combination as provided by a multifunction pump valve, piston and cylinder facilitated by a valve crowd assembly integrated into a hydraulic cylinder as accomplished by the present invention as herein disclosed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings, which are incorporated in and constitute a part of this specification illustrate embodiments of the invention and, together with the description, serve to explain the features, advantages, and principles of the invention. 
           [0011]      FIG. 1  is a isometric view of an embodiment of the press pliers according to the present invention wherein the essential features of the apparatus are visible including the upper stationary handle, jaws, release lever and lower moving handle. 
           [0012]      FIG. 2  is a top plan view of the press pliers of  FIG. 1 . 
           [0013]      FIG. 3  is a side elevation cross sectional view taken along Line  3 - 3  of  FIG. 2  wherein showing the spatial relationship of the various elements according to the present invention. 
           [0014]      FIG. 4  is a sectional view of the illustration of  FIG. 3  showing the press pliers in the forward stroke configuration wherein the crowd assembly and hydraulic pump assembly compress hydraulic fluid in the pump cylinder by the lower moving handle lever activation. The hydraulic fluid is further forced into the tool cylinder cavity by fluid transfer from the pump cylinder. 
           [0015]      FIG. 5  is a sectional view similar to the illustration of  FIG. 3  showing details of the various elements of the crowd assembly, the hydraulic pump piston assembly and the release collar. The elements have a spatial relationship consistent with the forward stroke configuration of the press pliers. 
           [0016]      FIG. 6  is a sectional view according to the present invention similar to  FIG. 5  showing details of the various elements of the crowd assembly, the hydraulic pump piston and cylinder wherein the pump piston is disposed within the pump cylinder with the release collar being depressed by the release lever cam thrusting the push off pin of the pump piston forward. The elements have a spatial relationship consistent with the reverse stroke configuration of the press pliers. 
           [0017]      FIG. 7  is a sectional view according to the present invention similar to  FIG. 4  illustrating the back stroke configuration wherein the lower moving handle lever is retracted from the crowd assembly thereby moving the crowd assembly outwardly from the pump piston assembly facilitating a replenishment of the pump cylinder with hydraulic fluid from the hydraulic fluid reservoir thereby preparing the pump for the next forward stroke. 
           [0018]      FIG. 8  is a sectional view according to the present invention similar to  FIG. 4  illustrating the reversing or release configuration wherein the various elements are arranged to relieve the hydraulic pressure within the tool cylinder when activated by disposing the release lever cam over the release collar of the hydraulic pump assembly absent forward motion of the crowd assembly and moving the pump piston forward into the pump cylinder wherein the push pin portion of the pump piston is disposed to lift the pump check valve ball and relieving hydraulic fluid from the tool cylinder. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. Referring now in greater detail to the various figures of the drawings wherein like reference characters refer to like parts, there is shown in an isometric view at  10  in  FIG. 1 , a new type of hydraulically activated press pliers hand tool. 
         [0020]      FIGS. 1 and 2  illustrate the press pliers  10  according to the present invention having an upper stationary handle  12  having a tubular rear portion  20  and an upper serrated jaw portion  36  forming the front end of the handle  12 . The upper serrated jaw portion  22  has serrations  24  disposed downwardly and opposing lower serrated jaw  26  upwardly facing serrations  28  for engaging and gripping a work piece provided by a user. A lower moving handle  14  is provided with optional lower moving handle grip  32  and arranged to activate a hydraulic cylinder assembly centrally disposed within the upper stationary handle  12 . The lower jaw pivots towards the upper jaw with increasing pressure as a user repeatedly squeezes the lower and upper handles together. The hydraulic pressure on the jaws is released when release handle  16  is depressed by a user. Lower serrated jaw lip  40  provides a lever handle for a user to manually spread the jaws apart when the hydraulic pressure is released. 
         [0021]    Referring now to  FIG. 3  showing a full cross section of the invention, details of the various elements of the press pliers are illustrated showing the press pliers tool comprising an upper stationary handle  12  having a tubular rear portion  34  and an upper serrated jaw portion  24  forming the front end of the handle  12 , a lower serrated jaw  26  being pivotally fixed at the pivot end to the upper stationary handle  12  by the lower serrated jaw pivot pin  42 . The lower serrated jaw  26  has a front end with the serrations  28  disposed opposing the upper stationary handle  12  serrations  24 . A hydraulic cylinder assembly  50  is centrally and longitudinally disposed within the upper stationary handle  12 . The hydraulic cylinder assembly  50 , having a front and rear end, is pivotally attached to the tubular rear portion  20  of the upper stationary handle  12  by hydraulic cylinder assembly rear pivot pin  52 , the pivot pin  52  being horizontally and perpendicularly fixed to the inside diameter of the tubular rear portion  20  near the rear end of the handle  12 . An option upper stationary handle rear dust cap  36  may be provided disposed to cover the tubular portion  20  rear opening. The front end of the hydraulic cylinder assembly  50  is comprised of yoke  18  and is pivotally attached to the lower serrated jaw  26  by cylinder assembly front pivot pin  54 . Pivot pin  54  is fixed to the lower serrated jaw  26  at a location between the jaw pivot pin  42  and the serrated portion  28  of the lower serrated jaw  26 . The longitudinal length of the hydraulic cylinder assembly  50  extends when activated by the user thereby pressing against pivot pin  54  and necessarily leveraging lower serrated jaw  26  to rotate around jaw pivot pin  42  thrusting the serrations  28  upwardly towards the serrations  24  of the upper jaw  22  and hence engaging and gripping a work piece disposed between the serrations. 
         [0022]    The hydraulic cylinder assembly  50  essentially comprises a yoke  18  forming the front end, a tool piston assembly  68  fixed to the yoke  18 , a tool cylinder  74  slideably engaging the rear end of the tool piston assembly  68 , and a hydraulic fluid reservoir  108  around a portion of the circumference of the hydraulic cylinder assembly  50 . Hydraulic fluid flowing into the tool cylinder  74  during a forward stroke forces the tool piston assembly  68  outwardly extending the length of the hydraulic cylinder assembly  50 . The tool piston assembly  68  further comprises a hydraulic pump assembly  80  longitudinally and concentrically disposed within the tool piston assembly  68 . The hydraulic pump assembly  80  is activated by moving the lower moving handle  14  to depress the front end of the tool piston assembly  68  containing a crowd assembly  60  of the hydraulic pump assembly  80 . 
         [0023]    Again referring to  FIG. 3 , activation of the hydraulic cylinder assembly  50  is accomplished by rotating lower moving handle  14  towards the upper stationary handle  12  wherein the lower moving handle  14  is pivotally attached to the yoke  18  of the hydraulic cylinder assembly  50  by lower moving handle pivot pin  56  located near the proximate end of the handle  14 . The lower moving handle  14  has a pump lever  58  fixed near the proximate end and disposed to contact and press centrally on the crowd assembly  60  of the hydraulic piston assembly  100 . Similarly a release handle  16  is provided, pivotally attached at the release handle proximate end, to the lower moving handle  14  with a release lever cam  34  disposed to interfere with and engage the release collar  66  surrounding the crowd assembly  60  of the hydraulic pump assembly  80  when the distal end of the release handle  16  is activated by a user. As illustrated, the hydraulic cylinder assembly  50  is suspended between pivot pin  54  at the front end and the pivot pin  52  at the rear end, an arrangement that permits the hydraulic pump assembly  50  front yoke  18  to move with the lower serrated jaw  26  thereby eliminating the need for additional mechanical linkages that would be required if the hydraulic cylinder assembly  50  were fixed stationary within the upper stationary handle  12 . The arrangement has the further advantage of maximizing load transfer to the lower serrate jaw  22 . 
         [0024]    As shown in more detail in  FIG. 4 , the hydraulic cylinder assembly  50  tool cylinder  74 , forming the rear end of the assembly, slidably receives the outside circumference of the cylindrically shaped tool piston rod  76  portion of the tool piston  68  functioning as a piston for tool cylinder  74 . The tool cylinder  74  is cylindrically shaped having a bottom with a flange portion extending outwardly from the bottom of the cylinder  74 . The flange receives and retains the hydraulic cylinder assembly rear pivot pin  52  pivotally attaching the rear end of the hydraulic cylinder assembly  50  to the upper stationary handle  12 . The outside circumference of the rear portion of tool piston  68 , forming the tool piston rod  76 , is inserted into the tool cylinder  74  thus forming a hydraulic piston for the tool cylinder  74 . Tool cylinder seals  78  disposed around the tool piston rod  76  and within the tool cylinder  74  inside circumference confines hydraulic fluid within the cylinder  74  notwithstanding flow through the centrally disposed pump check valve  102 . As the tool piston  68  front end is fixed to yoke  18 , hydraulic fluid received by the tool cylinder  74  through check valve  102  necessary forces the two ends of the hydraulic cylinder assembly  50  apart analogous to the action of a typical hydraulic cylinder. 
         [0025]    The hydraulic pump assembly  80  is centrally and longitudinally disposed within the tool piston  68  comprising the pump cylinder  84 , the pump piston assembly  100  with the rear end being a pump piston  86  and the front end being a valve and manifold housing  88 , the pump ball valve  82  centrally disposed between the pump piston  86  and the valve and manifold housing  88 , and the crowd assembly  60  disposed within the valve and manifold housing  88  and contacting the pump ball valve  82 . As in  FIG. 4 , the pump piston  86  portion of the pump piston assembly  100  is cylindrically shaped and slidably received by the pump cylinder  86  with pump seal  92  disposed between the inside circumference of the pump cylinder  84  and the outside circumference of the pump piston  86  together forming a hydraulic piston pump within the apparatus. The crowd assembly  60  slidably disposed within the front end of the pump piston assembly  100  and being in direct contact with the lower moving handle pump lever  58  and further being in direct contact with the pump ball valve  82  closes the ball valve  82  when compressed while also transferring motion from the lower moving handle pump lever  58  directly to the hydraulic pump piston assembly  100  through the surrounding valve and manifold housing portion  88  forcing the pump piston portion  86  into the pump cylinder  84  producing a forward stroke of the pump to compress fluid within the pump cylinder  84 . 
         [0026]    In this forward stroke configuration of  FIG. 4 , crowd assembly  60  seats the pump ball valve  82  trapping hydraulic fluid within the pump cylinder  84  and compressing the fluid as the pump piston portion  86  moves into the pump cylinder  84  as accomplished by the motion of the lower moving handle  14 . With hydraulic fluid pressures high enough to overcome the check valve load spring  104  and fluid pressures within the tool cylinder  74 , the pump check valve  102  opens and fluid flows into the tool cylinder  74  increasing the volume and pressure within the tool cylinder  74  forcing the hydraulic cylinder assembly  50  to responsively lengthen. 
         [0027]    In  FIG. 5 , the hydraulic pump piston assembly  100  is illustrated separately wherein the piston portion  86  has a central cavity with hydraulic fluid flow connectivity to the pump ball valve  82  at the front end and a hydraulic fluid pathway at the rear end with connectivity with the pump cylinder  84 . The pump piston portion  86  further comprises a push pin  90  centrally and longitudinally disposed extending from the rear end of the pump piston portion  86  having a length sufficient to lift the tool cylinder check valve  102  from the valve seat for venting hydraulic fluid from the tool cylinder  74  as required during a reversing stroke. 
         [0028]      FIG. 6  shows pump piston portion  86  of the hydraulic pump piston assembly  100  being received by the pump cylinder  84  with the pump piston portion  86  fully inserted into the pump cylinder  84  as in the reversing stroke of the press pliers  10 . Note that push pin  90  is contacting and lifting pump check valve  102  open permitting hydraulic fluid flow back into the pump cylinder  84 , through the reservoir vents  136  of the pump piston assembly  100 , and eventually out through the tool piston assembly reservoir vents  138 . 
         [0029]    Of particular interest is the crowd assembly  60  disposed within the cylindrically shaped valve and manifold housing  88  being the front end of the pump piston assembly  100  as assemblage of elements is critical to the operation of the apparatus. The crowd assembly  60 , according to the present invention, is a key component of the hydraulic cylinder assembly  50  providing a means for combing multiple essential hydraulic pump elements into a single component thereby significantly reducing the cost and improving the reliability of tool. Referring to  FIGS. 5 and 6 , the crowd assembly  60  and piston ball valve  82  combination facilitates the three operating modes of the assembly; the forward stroke, the back stroke, and reversing or releasing stroke. The crowd assembly  60  comprises a cylindrically shaped crowd primary piston  110  slidably disposed within the front end of the valve and manifold housing  88  cavity having a circumferentially expanded portion  112  at the front end wherein the diameter of the expanded portion is equal to the outside diameter of the hydraulic pump piston assembly  100 . The front end of the crowd primary piston  110 , being solid, is pressed by the lower moving handle lever  58  moving the crowd primary piston  110  into the valve and manifold housing  88  cavity closing pump ball valve  82 . With the pump ball valve  82  now closed further depression of the lower moving handle  14  compresses crowd spring  114  centrally disposed within the valve and manifold housing  88 . The crowd spring  114  is captured between the rear end of the crowd primary piston  110  and crowd washer  116  being centrally secured by crowd spring bolt  118  threaded into the rear end of the crowd primary piston  110 . The crowd primary piston  110  longitudinal travel is limited inwardly by the interference of the raised ring portion  70  of release collar  66  and the front end of the pump piston assembly  80  as the raised ring portion  70  is disposed between the circumferentially expanded portion  112  of the release collar  66  and the front end of the piston assembly  100 . The outward longitudinal travel is limited by the interference between the crowd assembly pin  124  and the rear end of the crowd assembly capture slot  120  disposed through the diameter of the crowd primary piston  110 . Crowd wiper seal  122  disposed between the crowd primary piston  110  and the inside circumference of the valve and manifold housing  88  confines hydraulic fluid within the valve and manifold housing  88 . Slot  120  is elongated to allow the crowd primary piston  110  to move laterally. The crowd assembly pin  124  is perpendicularly fixed across the diameter of the valve and manifold housing  88  and through capture slot  120 . The crowd assembly  66  presses the pump ball valve  82  closed against pump ball valve seat  94  as the crowd assembly  66  is compress during a forward stroke sealing hydraulic fluid within the cavity of the pump piston portion  86  as in the configuration illustrated in  FIG. 5 . 
         [0030]    Returning to  FIG. 4 , during the forward stroke, the captured hydraulic fluid lifts the pump check valve  102  from its seat and flows into the tool cavity  74 . In the event of over pressuring of the press pliers, the crowd spring  118 , having a predetermined spring constant compresses, allowing pump ball valve  82  being biased open by pump valve spring  96  disposed around and between the ball valve pedestal  98  and the valve and manifold housing  88 , therein allowing hydraulic fluid to flow through the reservoir vents  136  penetrating the valve and manifold housing  88  then through the tool piston assembly reservoir vents  138  and back to the hydraulic fluid reservoir  108  encircling a portion of the outside circumference of the tool piston  68  and the a portion of the outside circumference of the tool cylinder  68  of the hydraulic cylinder assembly  50  and defined by a flexible hydraulic reservoir bladder  72 . 
         [0031]    In the back stroke configuration of  FIG. 7 , the lower moving handle  14  pivots downward from the tool upper stationary handle  12  in preparation for a subsequent compression by the user, the rotation is assisted by handle return spring  130  disposed between the release collar  66  and the tool piston  68 . The handle return spring  130  also retracts the pump piston assembly  100  when the release collar raised ridge  70  engages the crowd primary piston expanded portion  112 . During this back stroke, the pump ball valve  82  lifts from valve seat  94  by the bias of ball valve spring  96  around the pedestal  98 . The pump check valve  102  is now closed, holding fluid within tool cylinder  74 . Also during this back stroke, the pump piston portion  86  is retracted from the pump cylinder  84  thereby facilitating a hydraulic fluid flow from the hydraulic fluid reservoir  108  through the hydraulic fluid reservoir vents  136  and  138  past the now open pump valve  82  and into the pump cylinder  84  thereby replenishing lost fluid from the previous forward stroke. The pump cylinder  84  is now filled with fluid in preparation for the next forward stroke. 
         [0032]    In the release configuration of  FIG. 8 , the release lever cam  34  is rotated into position to interfere with the release collar  66 . The release lever cam  34  is pivoted around release lever pin  62  fixed to the lower moving handle  14  and into position when the user depresses the release lever handle  16  whilst also depressing the lower moving handle  14 . The motion compresses the handle return spring  130  until the release collar  66  contacts the valve and manifold housing  88  of the hydraulic pump piston assembly  100 . The pump piston portion  86  is pressed further into the pump cylinder  84  whilst the crowd assembly  60  remains inactive and disengaged from the pump ball valve  82  permitting the ball valve  82  to lift from the valve seat  94  providing direct hydraulic fluid connectivity between the pump cylinder  84  and the hydraulic fluid reservoir through hydraulic fluid reservoir vents  136  and  138 . As the hydraulic pump piston assembly  100  moves deeper into the pump cylinder  84 , the piston push pin  90  lifts the pump check valve  102  from the valve seat  104  allowing fluid within the tool cylinder  74  to flow back into the pump cylinder  84 . In this reversing or releasing configuration there is direct hydraulic fluid communication between the tool cylinder  74  and the hydraulic fluid reservoir  108  thereby allowing the fluid volume and pressure to vent allowing the hydraulic cylinder assembly  50  to shorten in length. The low pressure within the hydraulic cylinder assembly  50  relieves the pressure between the serrated jaws  22  and  28  releasing a work piece disposed between the jaws. The tool piston  68  may now be moved into the tool cylinder further as the hydraulic fluid pressure is now relieved allowing the shortening of the hydraulic cylinder assembly  50 . Releasing the hydraulic fluid with the reversing lever  16  allows the hydraulic fluid to return to the reservoir  108  releasing the pressure on a work piece; however, retraction and separation of the jaws  22  and  26  requires a further shortening of the hydraulic cylinder assembly  50 , is user facilitated by a downward movement of the lower serrated jaw  26 . The lower serrated jaw lip  40 , disposed on the front end of the lower serrated jaw  26  provides a lever for a user to depress to accomplish retraction and separation of the jaws  22  and  26  with the tool in this reverse or release configuration.