Patent Publication Number: US-6668613-B2

Title: Hydraulic compression tool and hydraulic compression tool motor

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to hydraulic compression tools and, more particularly, to drives for hydraulic compression tools having rotary motors. 
     2. Brief Description of Earlier Developments 
     Hydraulic power tools are used in numerous applications to provide users with a desired mechanical advantage. One such application is in crimping tools used for making crimping connections, such as for example, crimping power connectors onto conductors, or grounding connectors onto grounding wires. Other applications include jacking devices, presses and so on. In these cases, many operators desire that the hydraulic tools be powered, or in other words that the hydraulics be actuated by a motor merely at the flip of a switch or the press of a button. Naturally, a powered hydraulic tool does away with manual pumping by the operator to actuate the hydraulics, and hence, involves much less physical effort on the part of the operator to operate the tool. In addition to the significantly smaller physical effort, another desired advantage of the powered hydraulic tool compared to manual hydraulic tools, is that the powered tool may be faster. This allows tasks to be accomplished with the tool to be completed faster with a resulting reduction in cost. Indeed, for portable hydraulic tools, such as for example, hydraulic crimping tools, which are held and supported in the hands of the operator, the operating speed (e.g. how quickly the hydraulic ram is traversed through its stroke) of the tool becomes even more important. The quicker the task can be completed, the sooner the operator can put the tool down. Powered hydraulic tools are more complex, and hence more expensive as a rule, than their manually actuated counterparts. The added complexity may also tend to make powered hydraulic tools more susceptible to breakdown. This may be frustrating to the operator, as well as costly especially for tools used in the field where repair may not be readily available. Conventional powered hydraulic tools which employ a piston pump to operate the hydraulics generally may have a spring loaded piston to provide impetus to the piston in at least one direction and/or a camming mechanism capable of reciprocating the piston during operation. 
     U.S. Pat. No. 6,206,663 discloses one example of a piston pump for a hydraulic tool wherein the pump has a low-pressure delivery piston which is spring loaded to drive the piston to achieve fluid delivery at low pressure. The low pressure piston is moved back counter to the spring load prestress by a high pressure piston moved by a rotating shaft. 
     Another example is disclosed in U.S. Pat. No. 5,727,417 in which the hydraulic drive tool has a drive assembly with a wobble plate providing axial displacement to a spring loaded piston. The spring preload on the pistons returns the pistons to a fluid delivery starting position. Still other examples are disclosed in U.S. Pat. Nos. 5,111,681 and 5,195,354 in which a motor driven hydraulic tool has a motor operatively connected to a hydraulic pump via a cam link mechanism. The cam link mechanism has a plunger with a ring shaped fitting portion which has an eccentric shaft fitted therein to rotate freely. 
     The present invention overcomes the problems of conventional hydraulic tools as will be described in greater detail below. In accordance with one aspect of a preferred embodiment, the piston pump is springless, reciprocated by a cam link mechanism to the motor without assistance from spring preload. Moreover, in accordance with another aspect of the preferred embodiment, the cam link mechanism between the motor and piston is simple to manufacture and install, employing large bearing surfaces which reduces the cost of the tool while increasing reliability. These aspects as well as others will be described in greater detail below. 
     SUMMARY OF THE INVENTION 
     In accordance with a first embodiment of the present invention, a hydraulic tool drive is provided. The hydraulic tool drive comprises a frame, a hydraulic ram, a pump, a motor, and a link. The frame has a hydraulic reservoir. The hydraulic ram is movably mounted to the frame. The pump has a pump piston for pumping hydraulic fluid to move the hydraulic ram relative to the frame. The motor is connected to the frame. The motor has an output shaft which rotates about an axis of rotation when the motor is operating. The link operably connects the output shaft to the pump piston for generating a reciprocating movement of the pump piston relative to the pump when the motor is operated. The link is rotatably mounted on the output shaft and is pivotable at least at one end relative to the frame, wherein at least one end of the link is pivotally connected to the pump piston by a pin. 
     In accordance with another embodiment of the present invention, a hydraulic tool drive is provided. The tool drive comprises a frame, a hydraulic ram, a pump, a motor, and a collar. The frame has a hydraulic reservoir. The hydraulic ram is moveably mounted to the frame. The pump is connected to the frame. The pump has a pump piston for pumping hydraulic fluid to move the hydraulic ram relative to the frame. The pump piston is moveable relative to the pump along an axis of translation. The motor is connected to the frame. The motor has a rotary output shaft. The collar is connected to the rotary output shaft and has a joint at which the collar is moveably joined to the pump piston to move relative to the pump piston along another axis of translation which is substantially orthogonal to the axis of translation of the pump piston, wherein the collar comprise a frame with a generally cylindrical bore in which the rotary output shaft is eccentrically located, the frame having a clevis at one end which forms the joint in the collar. 
     In accordance with another embodiment of the present invention, a hydraulic tool drive is provided. The tool drive comprises a frame, a hydraulic ram, a pump, a motor, and a collar. The frame has a hydraulic reservoir. The hydraulic ram is moveably mounted to the frame. The pump is connected to the frame. The pump has a pump piston for pumping hydraulic fluid to move the hydraulic ram relative to the frame. The pump piston is moveable relative to the pump along an axis of translation. The motor is connected to the frame. The motor has a rotary output shaft. The collar is connected to the rotary output shaft and has a joint at which the collar is moveably joined to the pump piston to move relative to the pump piston along another axis of translation which is substantially orthogonal to the axis of translation of the pump piston, wherein the drive further comprises an eccentric fixedly mounted to the rotary output shaft, the eccentric being engaged to the collar so that when the motor rotates the rotary output shaft the collar is moved in an orbital motion relative to the output shaft. 
     In accordance with still another embodiment of the present invention, a hydraulic crimping tool is provided. The tool comprises a frame, a hydraulic ram, a pump, a motor, and a transmission. The frame has a hydraulic reservoir. The hydraulic ram is movably mounted to the frame. The pump is connected to the frame. The pump has a pump piston for hydraulically moving the hydraulic ram relative to the frame. The motor is connected to the frame. The motor has a rotary output shaft to the pump piston. The transmission comprises an eccentric. The eccentric is fixable mounted onto the rotary output shaft. The transmission comprises a collar rotatable mounted onto the eccentric to rotate relative to the eccentric. The collar is movably joined to the pump piston, wherein the collar has a clevis, the pump piston being pinned to the collar in the clevis. 
     In accordance with yet another embodiment of the present invention, a transmission for connecting a rotary motor output shaft to a rectilinear actuator which is movable rectilinearly along an actuator axis of translation is provided. The transmission comprises a frame, an eccentric, and a rectilinear guide. The frame has a bore formed therein. The eccentric is adapted to position the frame on the rotary motor output shaft. The eccentric is rotatably mounted in the bore of the frame to rotate relative to the frame. The rectilinear guide is connected to the frame. The rectilinear guide has a slide surface adapted to slidably seat against the rectilinear actuator allowing the frame to slide substantially rectilinearly relative to the rectilinear actuator, wherein the frame has a recess formed therein, the recess being sized and shaped for movably locating at least part of the rectilinear actuator in the recess, the rectilinear guide extending across the recess. 
     In accordance with a further embodiment of the present invention, a hydraulic tool drive is provided. The hydraulic tool drive comprises a frame, a hydraulic ram, a pump, a motor, and a link. The frame has a hydraulic reservoir. The hydraulic ram is movably mounted to the frame. The pump has a pump piston for pumping hydraulic fluid to move the hydraulic ram relative to the frame. The motor is connected to the frame. The motor has an output shaft which rotates about an axis of rotation when the motor is operating. The link operably connects the output shaft to the pump piston for generating a reciprocating movement of the pump piston relative to the pump when the motor is operated. The link is rotatably mounted on the output shaft and is pivotable at least at one end relative to the frame, wherein the link has an end which is movably mounted to the pump piston so that the link moves freely relative to the pump piston. 
     In accordance with another embodiment of the present invention, a hydraulic tool drive is provided. The hydraulic tool drive comprises a frame, a hydraulic ram, a pump, a motor, and a link. The frame has a hydraulic reservoir. The hydraulic ram is movably mounted to the frame. The pump has a pump piston for pumping hydraulic fluid to move the hydraulic ram relative to the frame. The motor is connected to the frame. The motor has an output shaft which rotates about an axis of rotation when the motor is operating. The link operably connects the output shaft to the pump piston for generating a reciprocating movement of the pump piston relative to the pump when the motor is operated. The link is rotatably mounted on the output shaft and is pivotable at least at one end relative to the frame, wherein the link has a recess at one end, at least one end of the pump piston being located in the recess. 
     In accordance with yet another embodiment of the present invention, a transmission for connecting a rotary motor output shaft to a rectilinear actuator which is movable rectilinearly along an actuator axis of translation is provided. The transmission comprises a frame, an eccentric, and a rectilinear guide. The frame has a bore formed therein. The eccentric is adapted to position the frame on the rotary motor output shaft. The eccentric is rotatably mounted in the bore of the frame to rotate relative to the frame. The rectilinear guide is connected to the frame. The rectilinear guide has a slide surface adapted to slidably seat against the rectilinear actuator allowing the frame to slide substantially rectilinearly relative to the rectilinear actuator, wherein the rectilinear guide comprises a pin, an outer surface of the pin forming the slide surface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and other features of the present invention are explained in the following description, taken in connection with the accompanying drawings, wherein: 
     FIGS. 1-1A respectively are a schematic view of a hydraulic compression tool and perspective view of part of the tool incorporating features in accordance with one embodiment of the present invention; 
     FIG. 2 is a cross-sectional elevation of a head section and pump body of the hydraulic compression tool in FIG. 1; 
     FIG. 3 is a perspective view of motor and handle portion of the hydraulic compression tool seen from a direction opposite to the direction of the view in FIG. 1; 
     FIG. 4 is a partial cross-sectional elevation view of the pump body and a power transmission of the hydraulic compression tool in FIG. 1; and 
     FIG. 5 is a perspective view of a portion of the housing for the power transmission of the hydraulic compression tool in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, there is shown a schematic view of a drive  100  used with hydraulic tool  10  incorporating features of the present invention. Although the present invention will be described with reference to the single exemplary embodiment shown in the drawings, it should be understood that the present invention can be embodied in many alternate forms of embodiments. In addition, any suitable size, shape or type of elements or materials could be used. 
     The present invention is described below with particular reference to a portable hydraulic tool  10  and the drive therefor, though the invention is equally applicable to any suitable type of hydraulic power tool. Referring also to FIGS. 1A-2, which show a partial perspective view and cross-sectional elevation view of the hydraulic crimping tool  10 , the tool generally comprises a head section  12 , a hydraulic power section  14 , a motor section  100 , and a handle  4 . The head section  12  is connected to the hydraulic power section  14 . The motor section  100  is connected to the hydraulic power section  14  generally opposite the head section. The handle section, used by the operator to support and position the tool, may extend from the hydraulic power section, also generally opposite the head section, and may incorporate the motor section at least in part. The head section generally has a static or anvil adapter  16  and movable adapter  18 . The anvil adapter  16  is located at one end of the head section. The movable adapter  18  is movably seated in the head section. The hydraulic power section  14  generally has a hydraulic cylinder  20 , a ram assembly  22 , and a pump body  24 . The ram assembly  22  is located in the cylinder  20  and is connected to the movable adapter  18  in the head section. The pump body  24  is connected to the hydraulic cylinder  20 . The hydraulic power section  14  has a pump  26  (see also FIG. 2) located in the pump body for pumping hydraulic fluid through the pump body into the hydraulic cylinder. The handle may include a reservoir  27  (see FIG. 2) for hydraulic fluid used in the hydraulic power section. The motor section  100  generally has a suitable electromechanical motor  102  having an EMF shield  103  covering the brush portion thereof and which powers a drive shaft  104  (in phantom). Drive shaft  104  and motor  102  are connected to transmission linkage  106  via gearbox  105  and adaptor plate  102   a.  The drive shaft  104  is connected by transmission linkage  106  to the pump  26 . When the pump  26  is operated by the motor  102 , hydraulic fluid from reservoir  27  is pumped through the pump body  24  to the hydraulic cylinder  20  and the ram assembly  22  therein. Hydraulic fluid presses against ram assembly  22  thereby advancing the ram  30  or assembly  22 , and the movable adapter  18 , connected to the ram  30 , towards the anvil  16 . The transmission linkage  106  connecting the drive shaft  104  in the motor section  100  and the pump  26  converts rotary motion of the drive shaft into rectilinear reciprocating translation of the pump as will be described in greater detail below. 
     One embodiment of the hydraulic tool will be described in detail below with specific reference to the crimping tool  10  shown in FIG. 1, although as noted before the present invention is equally applicable to any suitable kind of hydraulic power tool. As seen best in FIGS. 1-2, in this embodiment, the head section  12  of the tool  10  generally has a base or collar section  42  for connecting the head section to the rest of the tool, and an upper section  44 . The upper section  44  depends from the collar section  42 . The head section  12  may be a one piece member made from suitable metal by drop forging or casting, or alternatively the section may be an assembly of independently manufactured parts. The upper section  44  may have a general scallop or general C shape, as shown in FIG. 1A, which defines a workspace  48  in the head section  12 . In alternate embodiments, the head section structure may have any other suitable configuration providing a workspace in which work pieces may be placed into the head section. The upper section  44  has a longitudinal portion  45 , which forms the back or spine of the C shape, and an upper end  46 . The longitudinal portion  45  may be a space frame with inner and outer walls  50 ,  52  tied to each other by truss supports and curved beam end portions. The truss supports are arranged to form a series of voids in the longitudinal portion  45  which significantly reduces the weight of the head section  12  without loss in structural strength and rigidity. Reinforcing ribs  60  may be formed alongside the inner wall  50 , as shown in FIG. 1A, in order to further increase the rigidity of the head section  12 . 
     As can be realized from FIG. 1A, upper end  46  of section  44  is generally curved and forms the anvil adapter  16  at the top of the workspace  48  in the head section. As seen in FIG. 1A, in the preferred embodiment, a bore  63  is formed through the upper end  46  to the seating surface  62  of the anvil adapter  16  for mounting a die (not shown) to the anvil adapter. The curved seating surface  62  may provide a working surface against which work pieces having a round outer surface with a diameter complementing surface  62  may be seated. In the case where the work piece does not have a round outer surface which complements surface  62 , a die may be mounted using bore  63  to the anvil adapter allowing the work piece to be stably supported from the anvil adapter. The anvil adapter  16  has outer and inner stop surfaces  64 ,  66  which stop the travel of the movable adapter  18  in the work space  48  (see FIG.  1 A). The inner surface  32  of the inner wall  50  is substantially flat, as seen in FIG. 1A, and provides a guide surface to adapter  18  as will be described below. As seen in FIG. 1A, in this embodiment the collar section  42  has a generally cylindrical shape with a cylindrical bore  74  (See FIG. 2) formed therein. In alternate embodiments, the base section of the head section may have any other suitable shape for mating the head section to the hydraulic power section  14  of the tool. In the preferred embodiment, the cylindrical collar section  42  has a lower part  76  and an upper part  78 . Similar to the exterior of the collar section, the bore  74  also has a lower portion  74 L, located in the lower part  76  of the collar, and an upper portion  74 U located in the upper part  78 . The lower portion  74 L is threaded to engage the threaded upper end of the power section  14 . The upper portion  74 U of the bore is sized to form a close running fit with the ram  30  in the hydraulic power unit. The inner surface  84  is substantially smooth and forms a bearing surface for ram  30  as will be described in greater detail below. An annular groove  85  is formed into inner surface  84  for a wiper seal  86  or O-ring. 
     The movable adapter  18  is preferably a one-piece member which may be cast, forged, or fabricated in any other suitable manner. The movable adapter  18  has an upper or working end  90  which faces towards the anvil adapter  16  at the top of the workspace  48  when the movable adapter is mounted in the head section  12 . The lower end  94  of the movable adapter may have a flat seating surface with may a projecting boss  92  to radially interlock adapter  18  to piston  30  and a fastener may be used to secure the adapter to the ram  30 . As seen in FIGS. 1A-2, the body of the movable adapter  18  between the upper and lower ends  90 ,  94  has a flat face  98  positioned towards the inner surface  32  when the adapter is installed into the head section  12 . The flat face  98  is seated substantially flush against the inner surface  32  of the longitudinal portion  45  of the head section  12 . As can be realized from FIGS. 1A-2, the interface between the flat inner surface  32  and the flat face  98  of the movable adapter, maintains the movable adapter  18  generally aligned with the anvil  16  and prevents any rotation of the movable adapter  18  as it is advanced by the ram  30  towards the anvil  16 . 
     Referring now again to FIG. 2, the hydraulic power section  14  which is mated to the collar section  42  of the head section  12  has a housing  15  which includes both the hydraulic cylinder  20  and the pump body  24 . As noted before, the hydraulic power section  14  also has ram assembly  22 , though the hydraulic power section may use any suitable ram. The ram assembly  22  is movably mounted to the housing  15 . As shown in FIG. 2, ram assembly  22  generally comprises outer ram  30 , spring  300 , spring holder  302  and rapid advance ram actuator  28 . The spring holder  302  may be an elongated, one-piece member having a generally cylindrical shape. The holder  302  may have an end  304 , with a threaded portion or other means for fixedly mounting the holder into the housing  15 . The holder  302  also has a main section  308  with an external radial flange  312  projecting outwards. The flange  312  has a spring support surface  316  facing the threaded end  304  of the holder and ram seating surface  314  located on the flange opposite the support surface  316  (see FIG.  2 ). As seen in FIG. 2, the spring holder  302  has a chamber  320  formed into the main section  308 . The chamber  320  forms a hydraulic cylinder for the rapid advance actuator  28 . The opening of the chamber  320  is located in the flanged end of the holder. The spring holder  302  also has a hydraulic fluid passage  326  which communicates with chamber  320  as seen in FIG.  2 . The spring  300  in the ram assembly  22  may be a helically wound coil spring. 
     As shown in FIG. 2, the rapid advance ram actuator  28  generally includes an actuator body, spring loaded ball valve  330  and set screw. The body of the actuator  28  has a diameter sized to form a close sliding fit within chamber  320  in the spring holder  302 . The length of the actuator body is sufficient to advance the outer ram  30  through the full range of ram travel allowed by hydraulic cylinder  20 . The exterior of the body may have one or more O-ring grooves for O-rings  338  (only one is shown in FIG. 2) which form a hydraulic seal between the actuator  28  and chamber  320  in the spring holder  302 . As seen in FIG. 2, in this embodiment the actuator body has a hydraulic fluid passage  332  extending through the body allowing fluid to pass through the actuator to the ram  30 . The passage  332  includes an expanded chamber with an appropriate seat for the spring loaded check valve  330 . The passage terminates in a threaded hole for the set screw used to set the pressure at which the valve  330  opens. The ram  30  has an upper shaft section  344 , and an enlarged lower piston section  346 . The piston section  346  is sized and is provided with one or more O-rings  357  (only one is shown in FIG. 2 for example purposes) to form a hydraulic seal between the piston  346  and cylinder  20 . The upper shaft section  344  of ram  30  is sized to form a close sliding fit with the upper portion  74 U of the bore in the collar section  42 . The upper end of the shaft section  344  provides a mating surface for mounting movable adapter  18 . The outer ram  30  has an inner chamber  356  formed therein. The opening of the inner chamber is at the rear end  354  of the ram  30 . The length of the inner chamber  356  is sufficient to admit the main section  308  of the spring holder  302  therein when the ram  30  is fully retracted as shown in FIG.  2 . As can be realized from FIG. 2, the surface of the chamber  356  is part of the hydraulic fluid contact surface  352  of the ram  30 . 
     The ram assembly  22  may be assembled by inserting the rapid advance actuator  28  into the chamber  320  of the spring holder  302 , then inserting the holder  302 , and spring  300  into chamber  356  of ram  30  and mounting retention ring  301  into the chamber. The retention ring  301 , which may be mounted into a groove in the chamber  356 , holds the spring  300 , spring holder  302  and actuator  28  inside the ram  30 . The ram assembly  22  may them be installed into the housing  15 . 
     Still referring now to FIGS. 1A-2, the housing  15  of the power section  14  is preferably a one-piece member which as noted before includes the hydraulic cylinder  20  and the pump body  24 . In alternate embodiments the power section may have a housing assembly comprising a number of housing parts. As seen in FIG. 2, the hydraulic cylinder  20  is located in the upper portion of the housing  15 . The annular flange  80  in the head section forms the upper end of the cylinder. The length of the cylinder is such that the ram  30  is provided with sufficient travel to advance the movable adapter  18  from the retracted position shown in FIG. 2 to a position (not shown) abutting the stops  64 ,  66  of the anvil  16 . The housing  15  has a bore  262  opening into the bottom of the hydraulic cylinder  20  for mounting the spring holder  302 , and hence the ram assembly  22  into the housing. The pump body  24  of housing  15  includes a hydraulic fluid conduit system  25  connecting the hydraulic cylinder  20  to the fluid reservoir  27 . The pump  26  is located in the conduit system  25 . The pump  26  is shown as being a one stage piston pump, although multi-stage pumps may be used equally well with the present invention. The conduit system  25  in pump body  14  shown in FIG. 2 is merely an example of a suitable conduit system, and the hydraulic tool may use any other suitable conduit system. The conduit system  25  may have a suction conduit  210  and a supply conduit  212 . The conduit system  25  may also have a drain or return conduit  214 . The suction conduit  210  may extend between the reservoir  27  and the hydraulic chamber  20 . The suction conduit supplies hydraulic fluid to the hydraulic chamber to allow free movement to the ram  30  when advanced by the ram actuator  28 . The suction conduit  210  may have a check valve (not shown) which is closed by fluid pressure in the hydraulic cylinder. The suction conduit  210  also supplies fluid to the supply conduit  212  which communicates with suction conduit  210 . The supply conduit  212  may have a check valve (not shown) to prevent reverse flow from the supply conduit into the suction conduit when the supply conduit is pressurized by the pump  26 . The supply conduit has pump chamber or bore  222  for pump  26 . Downstream of pump chamber  222 , and hence pump  26 , the supply conduit  212  has a check valve  224  which prevents reverse flow in the conduit  212  when the pump  26  is in the suction stroke. Downstream of valve  224 , the supply conduit  212  is routed to its discharge port in the bottom of bore  262 . Thus, supply conduit  212  supplies hydraulic fluid to the chamber  320  to advance the actuator  28  in the spring holder  302 , and when valve  330  is opened by ram  30  meeting resistance, the conduit supplies fluid into chamber  20 . The supply conduit  212  also communicates with the drain conduit  214  to allow drainage of fluid from the supply conduit as well as the actuator chamber  120  in the spring holder  102 . In addition, a portion of the drain conduit  214  extends between the bottom of the hydraulic chamber  20  and the reservoir  27  thereby allowing fluid to drain from the hydraulic cylinder. The conduit  214  may have check valves (not shown) which close when fluid is pumped in the supply conduit  212 . The drain conduit  214  may also include a pressure sensing valve  228  which opens to drain the supply conduit  212  when an over pressure is sensed in the supply conduit or hydraulic chamber. The drain conduit  214  includes a plunger actuated valve  230  which when activated allows the supply conduit  212 , actuator chamber  320  and hydraulic chamber  20  to drain through conduit  214  into the reservoir  27 . 
     As noted before, the pump  26  is powered by the motor  102  in the motor section  100 . Referring now also to FIG. 3 which is a perspective view looking from front to rear, of the motor section  100  of the tool, the motor section  100  generally has a housing  101  enclosing the gear box  105 , a motor  102  with a drive shaft  104 , and a transmission linkage  106  (see FIG.  3 ). As seen in FIGS. 1A and 3, the housing has a rear section  101 R and a front portion  101 F. The rear housing portion  101 R houses the motor  102 , drive shaft  104  (See FIG. 3) for connection with a source of electricity via terminals  100 B. The front housing portion  101 F connects the motor section  100  to the housing  15  and houses the transmission linkage  106  between the drive shaft  104  and pump  26 . The rear housing portion  101 R is shown in FIGS. 1A and 3 as having a generally cylindrical shape, though in alternate embodiments the housing may have any suitable shape. The housings are configured to support the motor  102  therein and may include suitable brackets (not shown) for mounting the motor casing to the housing. 
     As seen in FIG. 1A, the front portion  101 F of the housing  101  preferably includes a support plate  120 , and a cover  122 . In alternate embodiments, the front portion of the housing may have any other suitable configuration. The support plate  120  is at the rear and the cover  122  is at the front. The cover  122  may be removably mounted to both the support plate  120  and housing  15  as will be described in greater detail below. As seen best in FIG. 3, the support plate  120  may be is a substantially flat plate member which may be stamped from sheet metal or cut from plastic sheets. The support plate  120  may include a cutout  123  complementing the exterior of the pump body  24 . The support plate  120  may also have a number of fastener holes  124  for fasteners used to mount the cover  122  to the plate  120 . As can be realized, a bore (not shown) is formed into the plate  120  to allow output shaft  104  to extend through the plate. The support plate  120  may be attached to the front end  118  of the gear box  105  by any suitable means such as welding, brazing, or bonding using adhesives or fasteners. The front cover  122  is seen best in FIG.  5 . The cover may be a one-piece member made of metal which is cast or drop-forged, or otherwise may be made of plastic by injection molding for example. Further, the support plate  120  and cover  122  could be fabricated as a single piece instead of two separate components. The cover  122  has an end wall  126  surrounded on three sides by peripheral wall  128 . The peripheral wall  128  has a general U-shape. As seen in FIG. 5, at the ends  130  the wall  128  flares outward defining attachment pads  132  for attaching the cover  122  to the pump body  24 . The attachment pads  132  have curved seating surfaces  133  conforming to the curvature of the exterior of the pump body  24 . Fastener holes  134  are formed through the pads for mechanical fasteners (not shown) such as for example machine screws used to attach the cover  122  to the pump body. The peripheral wall  128  has a rear seating surface  135  for seating against the support plate  120 . The seating surface may be substantially flat or may be provided with a groove for a seal gasket (not shown) to be placed between the cover and support plate at mounting. Longitudinal fastener holes  136  are included in the peripheral wall  128  corresponding to fastener holes  124  in the support plate  120 . End wall  126  has a bore  138  used to mount an end bearing (not shown) supporting the front end  105  of the output shaft  104  (see FIG.  3 ). A bearing (not shown) may be installed into bore  138  to close the front of the bore. The end wall  126  and peripheral wall  128  form a chamber  140  sufficiently deep to accommodate the transmission linkage  106  inside the chamber. Bore  138  is located in end wall  126  so that when the cover  122  is mounted to support plate  120 , the bore  138  is aligned with the output shaft  104 . 
     The motor  102  is preferably a single speed DC motor, although any suitable electro-mechanical motor may be used including an AC motor. An example of a suitable motor is an 18V DC Mabuchi motor, model RS-775 WC.8514. An advantage of the DC motor is that it may be readily powered using conventional batteries. A suitable reduction gear box  105  is mated to the drive shaft of the motor  102 . For example, in the event the rotary speed of the motor drive shaft is higher than the desired rotary speed of the output shaft  104  at the transmission  106 , the reduction gear box couples the motor shaft to the output shaft  104  such that the output shaft  104  would be coupled to an output end of the reduction gear. The reduction gear box may be of any suitable type such as for example, a planetary reduction gear rated for the rotary speed and torque of the motor. The reduction ratio across the reduction gear may be any suitable ratio to provide the output shaft  104  with a desired rotary speed. As noted before, the output shaft  104  may extend from the motor  102 , or in the case a reduction gear is used, from the output end of the gear to the transmission linkage  106 . The output shaft  104  may be solid or hollow, and may be made from metal such as for example steel or aluminum alloy, or from non-metallic materials such as plastic having adequate stiffness and strength to withstand the forces and torques which the shaft is subjected. As seen in FIG. 3, the output shaft  104  has a key  142  or other suitable interlocking features such as for example radial splines, or teeth with which to engage and transfer torque to a mating component. The output shaft  104  is supported by suitable bushings or bearings (not shown) to support torque and pump loads on the shaft. The output shaft  104  protrudes from plate  120  sufficiently for the front end  105  of the shaft to be rotatably supported in the bore  138  of the end wall  126  (See FIG.  5 ). The portion of the output shaft  104  extending in chamber  142  formed between the support plate  120  and end wall  126  in the front housing section  101 F provides a mounting surface for the transmission linkage  106 . 
     Referring now to FIGS. 3 and 4, the transmission linkage  106  generally includes eccentric  144 , bearing  146 , collar link  148  and slider mechanism  150 . The eccentric  144  and bearing  146  are used to rotatably mount the collar link  148  on the output shaft  104 , and the slider mechanism  150  is used to connect the collar link  148  to the pump  26  as will be described in greater detail below. The eccentric  144  is preferably a one-piece member which may be forged or machined from metal such as for example aluminum alloy. In alternate embodiments with low force environments, the eccentric may be made from non-metallic material such as plastic, ceramic or composite material having sufficient compression strength to withstand compression loads between the output shaft and collar link. As will be described further below, the mounting configuration of the eccentric  144  on the shaft  104  and in the collar link results in the compression loads between the collar link and shaft, during operation of the tool  10 , being distributed over a wide area. The eccentric  144  has a substantially circular outer surface  152 . The center of the outer surface  152  is located at location C 2  in the position shown in FIG.  4 . The eccentric  144  has a substantially circular inner bore  154  with the center located at location C 1  in the position shown in FIG.  4 . As can be realized from FIG. 4, the circular inner bore  154  is eccentric relative to the circular outer surface  152  with the corresponding centers (at locations C 1  and C 2  respectively) separated by a distance D. The distance D is about a half of the total stroke of the pump  26  in the pump body  24 . The inner bore  154  in the eccentric is shaped and sized to form a close or light press fit with the output shaft  104 . Accordingly, the inner bore  14  has a keyway  155  which closely conforms to the key  142  of the shaft  104 . The location of the keyway  155  in the eccentric  144  is shown in FIG. 4 as being substantially in line with the offset D between the center of the inner bore  154  and the center of the outer surface  152  only for example purposes, and in alternate embodiments, the keyway  155  may be positioned anywhere along the surface of the inner bore. The close fit between the inner bore  154  of the eccentric  144  and the output shaft  104  prevents impact or slap between eccentric and shaft operation, thereby preventing impact loads on the shaft and during eccentric, reducing operating noise and increasing pump efficiency. 
     In the preferred embodiment, the bearing  146  in the transmission linkage  106  is a radial caged needle bearing such as a Torrington® B 1210 bearing. The bearing  146  may be a sealed self lubricating bearing or an open bearing. In alternate embodiments, the bearing  146  may be any other suitable bearing or bushing rated to rotate at a rotational speed of up to about 1300 RPM or more for an indefinite time. The inner race (not shown) of the bearing is sized to form a light force fit with the outer surface  152  of eccentric  144 . 
     The collar link  148  is preferably a one-piece member although in alternate embodiments, the link may be an assembly of parts. The collar link may be made from metal, such as aluminum alloy by casting, forging or even pressing and sintering, or otherwise may be formed from plastic. In alternate embodiments with low force environments, non-metallic material such as plastic, or ceramic may be used. The collar link may have a main section  156  and a collar section  158  as seen in FIG.  4 . The main section  156  has a substantially circular bore  160  formed therein. The bore  160  has a center which is located at location C 2  when the collar link  148  is positioned as shown in FIG.  4 . The bore  160  is sized to form a light press fit with the outer race (not shown) of bearing  146 . As seen in FIG. 4, in the preferred embodiment, two arms  162  depend from the main section  156  at opposite edges of the clevis link and form the clevis section  158 . Also as seen in FIG. 4, each arm  162  has a bore  164  formed therethrough. The bores, 164  in each arm are aligned with each other and substantially orthogonal to the bore  160  in the main section  156 . The arms  162  define a recess  166  in between. In the preferred embodiment, the recess  166  is centrally located below  160 , though in alternate embodiments the recess may be offset from the bore. 
     Still referring to FIGS. 3 and 4 in the preferred embodiment, the slider mechanism  150  comprises a pin  168  and a sleeve bearing or bushing  170  capable of sliding freely upon the pin  168 . The pin  168  may be an elongated cylindrical member made from metal or plastic. The pin  168  is sized to be inserted through the bores  164  in the arms  162  of the collar link  148  as shown in FIG.  4 . At least a portion  172  of the pin has an outer surface with a surface roughness suitable for sliding bushing  170  back and forth over the pin without damage to the bushing. The outer ends of the pin  168  may form a press fit with the bores  164  in the clevis arms  162 . In addition the outer ends of the pin may have annular grooves (not shown) formed into the outer surface for snap rings  174  used to axially lock the pin into the collar link  148 . 
     As noted before, the slide mechanism  150  also includes slide bushing  170 . The slide bushing  170  is preferably a one-piece member. The bushing may be made from oil-impregnated bronze material, or from a lubricious plastic or composite material incorporating Teflon™ or from any other surface material. The bushing  170  has a cylindrical bore  176  sized to form a close sliding fit with the sliding portion  172  of the pin. This fit allows for the bushing  170  to slide freely along the pin  168  in the direction indicated by arrow X in FIG. 4, as well as rotate freely about the pin in the direction indicated by arrow R 1  in FIG.  3 . The close sliding fit between bushing  170  and pin  168  also ensures that there is no impact or slap between bushing and pin in a direction orthogonal to that indicated by arrow X in FIG.  4 . The exterior of the bushing  170  may have any suitable shape which allows the bushing to be located in recess  166  of the clevis section  158 . The bushing  170  may have an attachment section  174  for fixedly attaching the bushing to the pump  26 . For example, the attachment section  174  may include a post (not shown) which can be inserted into a mating bore in the pump, or conversely a collar (not shown) which may be placed around the pump to fixedly secure the bushings  170  to the pump  26 . The pin  168  and bushing  170  provide a pivotable joint  171  between the collar link  148  and pump  26 . 
     The transmission link  106  may be assembled and mounted to the output shaft  104  in a number of equally suitable ways, one of which is described below for example purposes. The eccentric  144  may be press fit into the inner race of bearing  146 . The bearing  146  may then be press fit into the bore  160  of the collar link  148 . The pin  168  may be inserted at any suitable time through the bores  164  of the clevis arms  162  securing the bushing in the collar link. The bushing  170  may be attached to the pump  26  before placement into the collar link  148  or after the bushing is secured to the link. After the pin  168  is inserted into the collar link  148 , snap rings  174  may be placed around the pin locking the pin axially in the link. The slip fit between the pin  168  and bores  164  allows the pin to spin in the bores though in alternate embodiments the pin may not be free to spin in the bores. In alternate embodiments, the pin may be staked or pinned to the clevis arms thereby fixing the pin in the link in all directions. The transmission linkage assembly  106  may then be mounted onto the output shaft  104 . 
     The transmission linkage  106  is mounted onto shaft  104  by sliding the eccentric  144 , which may be already positioned in the collar link as noted before, over the end  105   a  of the shaft  104 . The keyway  155  on the eccentric is aligned with the key  142  on the shaft  104 , and the shaft enters into bore  154  of the eccentric. As can be seen in FIGS. 3 and 4, the shaft centerline and axis of rotation of the shaft R is located at location C 1 , the center of the eccentric bore  154 . Hence, the shaft  104  is eccentric to the bore  160  in the collar link  148 , the shaft centerline at C 1  is being offset distance D from the center of bore  160  at C 2 . However, the shaft  104  contacts the surface of bore  154  in the eccentric around the circumference of the eccentric, and the outer surface of the bearing  146  contacts the surface of bore  160  in the collar link  148  around the circumference of the bearing. This allows the shaft  104  with the eccentric  144  thereon to rotate freely relative to the collar link  148 . Though the eccentric  144  is free to spin relative to the collar link  148 , the eccentricity between the axis of rotation R of the shaft  104  at C 1  and the center of the bore  160  at C 2  causes the eccentric to rotate about axis R relative to the collar link while moving the collar link  148  in an orbital motion about axis R. The orbit motion of the collar link  148  about axis R has an orbit radius equal to distance D (see FIG.  4 ). 
     After mounting the transmission linkage  106  in the shaft  104 , the end bearing (not shown) may be placed on end  105   a  of the shaft and the gear box  105  mounted to support plate  123 . The motor section  100  may then be mounted to the housing  15  as shown in FIG.  1 A. In the preferred embodiment, the pump  26  has already been secured to the slide bushing  170 . Accordingly, when the motor section  100  is placed against the housing  15 , the pump  26  is inserted into pump chamber  222  of the pump body  24 . The motor section  100  is then secured by inserting fasteners through the fastener holes  134  of the cover  122  (see FIG. 5) into the housing  15 . 
     After the motor section  100  is mounted to housing  15 , the tool  10  may be operated by energizing the motor  102 . The motor  102  is preferably provided with a control, such as an on/off switch with which the operator controls the motor. When energized, the motor rotates the output shaft  104  about axis R. As noted before, the rotation of the shaft  104 , with eccentric  144  thereon, causes the collar link  148  to move in an orbital motion about axis R. The orbital motion of the collar link  148  has components along orthogonal directions indicated by arrows X and Y in FIG.  4 . Collar motion in the direction indicated by arrow Y brings the pin  168  in the collar link  148  against the slide bushing  170  thereby actuating the pump  26  in the Y direction in and out of the chamber  222  in the pump body. Collar motion in the X direction slides the pin  168  inside the slide bushing  170 . Thus, the transmission linkage  106  transforms the rotational motion of the shaft  104  into reciprocating rectilinear motion of the pump  26  inside the pump body  24 . One revolution of the shaft  104  actuates the pumping through one in/out cycle in chamber  222 . Actuation of the pump  26  in the pump body  24  draws hydraulic fluid from the suction conduit  210  (see FIG. 2) and supplies it under pressure through the supply conduit  212  to the ram assembly  22  to move the movable adapter  18  of the tool  10 . 
     As can be realized from FIGS. 3 and 4, the freedom of movement of the pivotable joint between the collar link  148  and pump  26  accommodates misalignment between the motor section, particularly the location and angle of axis of rotation R relative to the location or shaft  104  of the pump bore  222  in the pump body. For example, if the motor section  100  when mounted to housing  15  and the shaft  104  is positioned such that axis R is inclined rather than orthogonal to bore  222 , or the collar link is not positioned directly over the bore  222 , the pivotable joint  171  between collar link  148  and pump  26  allows the pump  26  to nevertheless be installed true in the pump bore  222 , and the transmission linkage  106  to operate without binding or excessive wear of either the slider mechanism  150  or the bearing  146 . The pivotable joint  171  between pump  26  and link  148  allows the bearing  146  to remain true on the shaft  104  and in the collar link so that the bearing may rotate freely. The cylindrical surfaces of the pin  168  and slide bushing  170 , which effect the pivoting freedom of joint  171 , also allow the slide bushing  170  to slide freely along the pin (in the direction indicated by arrow X) regardless of whether the collar link  148  is angled relative to the pump  26 . 
     The full circumferential contact between the eccentric  144  and bearing  146  and the bearing  146  and collar link  148  provides large bearing surfaces which in turn reduces contact stress on these components with a commensurate reduction in wear and an increase in the life of the component. Similarly the large bearing surfaces between the pin  168  and slide bushing reduces contact stress between these components. For example, for a slide bushing  170  having a length of 0.5 inch and a pin with a diameter of 0.31 inch, the contact stress from a 750 lbs. load on the pump  26  is about 3100 psi. Stresses of this order of magnitude are low relative to the yield stress of many metal alloys including light and inexpensive aluminum allows without heat treatment. Contact stresses of the magnitude noted above may also be readily supported by non-metallic materials such as plastic without creep or deformation of the material. Aluminum alloys or plastic are inexpensive and easy to shape or machine. Aluminum alloys or plastic are also light. Thus, use of aluminum alloys or plastic in manufacturing components such as the transmission linkage  106  of the tool  10 , reduces the weight of the tool  10 , as well as manufacturing cost in comparison to conventional hydraulic power tools. The transmission linkage  106  continuously transfers power from the shaft  104  to the pump  26  actuating the pump both into and out of the pump chamber  222 . This facilitates very high pump speeds without limitations due to spring response as in conventional hydraulic tools. The high pump speeds achievable with tool  10  allow crimping operations to be completed faster than using conventional hydraulic crimping tools. 
     In sharp contrast to drive  100  and tool  10 , conventional hydraulic tools that use springs as the primary device to return the piston pump to its home position have several disadvantages. Springs have a finite life, require additional room to package, and can produce “valve hop”. Valve hop is a condition when the spring response does not coincide with the speed of the device. In hydraulic tools, the spring may cause “piston hop”, where the piston pump may not stay fully engaged with the drive shaft. Such a condition would produce less pump stroke and therefore a relatively longer crimp cycle time. In addition, the spring preload against the piston drives up the power demand during pump operation (i.e. the motor is working against hydraulic pressure and spring preload on the piston) thereby consuming more power. This is significant in battery powered tools. In the case of conventional hydraulic tools employing a cam link mechanism as disclosed in U.S. Pat. Nos. 5,111,681 and 5,195,354, the manufacture of such a mechanism may involve either welding of two components or considerable machining time. In addition, the parts of the cam mechanism would most likely need heat treatment. Also alignment of the annular portion of the mechanism to the shaft may be very difficult. It is preferred to have the needle bearing outer race in full contact with the contoured inner portion. However, in the conventional tools, the bearing is not in full contact and bearing life may be reduced. Also since the needle bearing outer race is allowed to translate within the contoured cavity, ample clearance may exist between the outer bearing race and contoured surface, primarily, clearance in the direction of piston pump movement. The subject clearance may be relatively small in this direction, however, such clearance is not desired because it may produce a “rapping” sound and create excessive wear. Wear can result because there is a substantial load being applied to a relatively small contact point. The contact point in this case is the apex of the needle bearing outer race. The present invention overcomes the above noted problems or conventional hydraulic tools as previously described. 
     It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.