Abstract:
A hydraulically actuated tool comprising a frame; a hydraulic fluid pump connected to the frame; a ram movably connected to the frame and adapted to be moved relative to the frame by hydraulic fluid pumped by the pump; and a hydraulic fluid reservoir connected to the pump. The reservoir is located proximate an exterior portion of the frame along a path of at least about 180°0 relative to a longitudinal axis of the tool. The reservoir does not extend beyond a rear end of the frame.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to hydraulic tools and, more particularly, to a reservoir of a hydraulic tool. 
     2. Prior Art 
     U.S. Pat. No. 5,727,417 discloses a portable battery powered crimper having a hydraulic drive assembly with a wobble plate. U.S. Pat. No. 5,472,322 discloses a hydraulic fluid tank with a flexible membrane. There is a desire to shorten the length of hydraulic tools to thereby decrease the weight of the tools. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention, a hydraulically actuated tool is provided comprising a frame; a hydraulic fluid pump connected to the frame; a ram movably connected to the frame and adapted to be moved relative to the frame by hydraulic fluid pumped by the pump; and a hydraulic fluid reservoir connected to the pump. The reservoir is located proximate an exterior portion of the frame along a path of at least about 180° relative to a longitudinal axis of the tool. The reservoir does not extend beyond a rear end of the frame. 
     In accordance with another embodiment of the present invention, a battery powered hydraulic compression tool is provided comprising a frame, a hydraulic fluid pump on the frame, a hydraulic fluid reservoir connected to the pump, and a ram movably connected to the frame. The improvement comprises the hydraulic fluid reservoir having a general ring shape surrounding a portion of the frame. 
     In accordance with another embodiment of the present invention, a battery powered hydraulic compression tool is provided comprising a frame, a hydraulic fluid pump on the frame, a hydraulic fluid reservoir connected to the pump, and a ram movably connected to the frame. The improvement comprises the hydraulic fluid reservoir having a general ring shape surrounding the pump. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and other features of the invention are explained in the following description, taken in connection with the accompanying drawings, wherein: 
     FIG. 1 is a side elevational view of a battery powered hydraulic crimping tool incorporating features of the present invention; 
     FIG. 2 is a partial cross-sectional view of the tool shown in FIG. 1; 
     FIG. 3A is a perspective view of a portion of an alternate embodiment of the present invention; 
     FIG. 3B is a partial cross-sectional view of the tool shown in FIG. 3A; 
     FIG. 4A is a perspective view of a portion of another alternate embodiment of the present invention; and 
     FIG. 4B is a partial cross-sectional view of the tool shown in FIG.  4 A. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a side elevational view of a tool  10  incorporating features of the present invention. Although the present invention will be described with reference to the embodiments shown in the drawings, it should be understood that the present invention may be embodied in many forms of alternate embodiment. In addition, any suitable size, shape or type of elements, members or materials could be used. 
     The tool  10  is a battery powered hydraulic crimping tool. However, in alternate embodiments features of the present invention could be used in hydraulic tools which are not battery powered and/or hydraulic tools other than electrical connector crimpers. The tool  10  generally comprises a housing  12 , a removable battery  14 , an electric motor  16 , a hydraulic pump  18 , a hydraulic fluid reservoir  20 , and a working head  22  having a movable ram  24 . The housing  12  in this embodiment forms a handle section  26 . However, any suitable housing or handle could be provided. The battery  14  is preferably a removable rechargeable battery. The electric motor  16  is adapted to operably move the pump  18 . However, features of the present invention could be used in a manually actuated hydraulic tool or an electrically powered tool not having a battery. An alternate embodiment might also include a non-removable battery. The working head  22  includes a frame  23  which forms an anvil surface  28  opposite a front end of the ram  24 . In this embodiment the working head  22  is a die-less working head (i.e.: no crimping dies are used). However, in an alternate embodiment the frame of the working head and the ram  24  could be adapted to receive removable crimping dies or cutting dies. 
     Referring also to FIG. 2, the tool  10  includes a frame member  30  which connects the motor  16  to the rear end of the frame  23  of the working head  22 . The frame member  30 , in the embodiment shown, is a one-piece member which forms a housing for the pump  18 , part of the hydraulic fluid reservoir  20 , and hydraulic chamber  32  for the rear end  34  of the ram  24 . However, in an alternate embodiment the frame member  30  could be comprised of multiple members and can contribute to fewer or more features. The pump  18  generally comprises a rotatable assembly  36 , a substantially rotationally stationary assembly  38 , pistons  40  and piston springs  42 . The substantially rotationally stationary assembly  38  generally comprises a first member  44  with piston movement areas  46  and spring mounts  48 , and a second member  50  with ball check valves  52  aligned with each piston movement area  46  and biased by a washer  54  towards a closed position. In this embodiment the pump  18  comprises three pistons  40  and associated respective piston movement areas  46  and ball check valves  52  equally spaced about a center axis of the pump. However, any suitable number or arrangement could be provided. The pistons  40  are located in the piston movement areas  46  for reciprocal movement and are biased by the springs  42  towards the rotatable assembly  36 . Rear ends of the pistons  40  pivotably sit on seats  56 . The seats  56  slidably rest against a slanted surface  58  of the rotatable assembly  36 . The pistons  40  each have a through hole or conduit  60  and push surface  62 . The rotatable assembly  36  generally comprises a wobble drive member  64  and a mount  66  for connecting the wobble drive member  64  to the electric motor  16 , such as via reduction gears (not shown). The slanted surface  58  comprises the front surface of the wobble drive member  64 . When the electric motor  16  is actuated, it rotates the rotatable assembly  36  such that the rotating slanted surface  58  and springs  42  cooperate to reciprocally move the pistons  40  to pump hydraulic fluid from a flood area  68  past the check valves  52  into the chamber  32  to push the rear end  34  of the ram  24  forward. Hydraulic fluid can be relieved from the chamber  32 , by manual actuation of relief valve assembly  70  and trigger  72 , back into the flood area  68 . The tool can comprise a spring  25  for moving the ram  24  back to its retracted position. The flood area  68  surrounds the pistons  40  and provides a continuous supply of hydraulic fluid which can enter into the through holes at the rear ends of the pistons  40  at the seats  56 . However, in alternate embodiments any suitable pump or relief system could be used. 
     In order to supply the pump  18  and flood area  68  with an adequate supply of hydraulic fluid for the full extension range of movement of the ram  24 . The flood area  68  is connected to the reservoir  20  by a single channel or conduit  74  through the frame member  30 . In this embodiment the tool  10  does not comprise any check valves between the reservoir  20  and the flood area  68 . In alternate embodiments the tool could have multiple conduits between the reservoir  20  and the flood area  68 , and/or could include check valve(s). The reservoir  20  includes a containment wall  76  connected to the frame member  30 . In this embodiment the containment wall  76  comprises a resilient member  78  and a rigid cover  80 . The resilient member or bladder  78  is able to expand and contract as hydraulic fluid is moved into and out of the reservoir  20 . Cover  80  prevents the bladder  78  from being inadvertently damaged. The containment wall  76  is connected to an exterior side of the frame member  30 . In this embodiment the frame member  30  includes a groove  82  along the exterior surface. The groove  82  has a general annular or circumferential shape. However, in alternate embodiments, the groove  82  of the frame member  30  could comprise more than one groove, have an alternative shape(s), or not fully surround the frame member  30 . Multiple reservoirs could also be provided. The reservoir  20  is formed by a combination of the groove  82  and the containment wall  76  surrounding the groove. However, in an alternate embodiment the frame member  30  might not have a groove; the reservoir being defined by the containment wall and a non-grooved surface of the frame member. Alternatively, the containment wall could substantially completely define the reservoir with a connection being provided to the conduit  74 . In the embodiment shown, the reservoir  20  has a general ring shape, but need not be uniformly circular or round. The reservoir  20  could have a partial ring or split ended ring shape or extend less than 360° around the frame member; such as only about 180°. However, any suitable angle could be provided, such as 120°-360°. Preferably, the reservoir  20  uses an outer surface of the frame member  30  to help define the reservoir. This helps to reduce the weight of the containment wall  76 . In addition, because the reservoir  20  is outside and surrounds the frame member  30 , and because of the relatively large inner and outer radii of the reservoir, the volume of the reservoir can be relatively large but comprise a relatively small reservoir length and height. 
     In the embodiment shown, the reservoir  20  surrounds part of the chamber  32  and the rear end  34  of the ram  24  when the ram is located in its rearward position. The reservoir  20  is located in front of the front end of the pump  18 . The conduit  74  extends in a general rearward direction from the reservoir to the flood area  68  and the pump  18 . However, in an alternate embodiment the reservoir could surround part of the pump  18 . The present invention provides an advantage in that the longitudinal length of the tool  10  can be reduced. This is because components (in this case the reservoir  20 , chamber  32  and part of the ram  24 ) can occupy a position in a same plane perpendicular to the longitudinal axis A (see FIG.  1 ). This shortening of the tool length can result in a lighter weight tool, but the shorter length tool can still produce the same longitudinal ram travel length as conventional tools. The present invention can use its three axial pistons with no pronounced pulsations, and is a very compact design. The rotatable assembly  36  can be mounted on a ball bearing assembly which will substantially decrease friction and increase mechanical efficiency. The pump  18  does not use internal seals. This can result in a longer mean time between failures, high reliability and high efficiency due to less internal leakage. The annular symmetrical bladder or reservoir  20  provides adequate reservoir capacity without increasing the tool&#39;s length or balance. Serviceability is also better than in conventional tools. The pump can preferably operate at about 550 bar or higher. The present invention can produce a relatively high number of crimps per battery charge due to the high mechanical efficiency. Contributing to the high efficiency are: lack of seals, mechanical balance, clean and unobstructed porting path for hydraulic fluid, lack of high inertial forces, use of bearings and efficient simple planetary gear reduction between the motor and pump. The pump is preferably bi-directional such that it can run in either direction. The present invention allows the tool to be gravity independent. In other words, the pump can operate in any orientation of the tool due to the bladder or reservoir design. The present invention allows the working head to comprise a latch style crimp head with lightweight ergonomic design. 
     Referring now to FIGS. 3A and 3B an alternate embodiment of the present invention is shown. In this embodiment a tool subassembly  100  is provided comprising a frame member  102 , a pump  104 , a ram  106  and rear part  108  of the working head. The pump  104  is similar to the pump  18  shown in FIG. 2 with a rotating assembly  110 , spring loaded pistons  112 , and a rotationally stationary assembly  114  with conduits into the hydraulic chamber  116  behind the rear end of the ram  106 . The frame member  102  surrounds the pump  104 . The frame member  102  in conjunction with a rear mounting plate  118  and cover  120  form an annular hydraulic fluid reservoir  122 . The frame member  102  has a conduit  124  from the reservoir  122  into a flood area  126  of the pump. This embodiment is intended to illustrate that the tool can be configured to surround the pump and does not need to surround the ram or the ram hydraulic chamber. 
     Referring now to FIGS. 4A and 4B another alternate embodiment of the present invention is shown. In this embodiment a tool subassembly  200  is provided comprising a frame member  202 , a pump  204 , a ram  206  and a rear part  208  of the working head. The pump  204  is similar to the pumps  18  and  104  with a rotating assembly  210 , spring loaded pistons  212 , and a rotationally stationary assembly  214  with conduits into the hydraulic chamber  216  behind the rear end of the ram  206 . The frame member  202  has a mount  218  for filling the reservoir  226  with hydraulic fluid and a mount  220  for connecting a hydraulic fluid supply and return line (not shown) for connection to an auxiliary pump (not shown). Conduit  221  extends between mount  220  and chamber  216  for moving the ram.  206  by moving hydraulic fluid through mount  220  and conduit  221 . A cover  222  is connected to the frame member  202  with a bladder or flexible resilient member  224  therebetween. An annular reservoir  226  is formed between the frame member  202  and the annular bladder  224 . The frame member  202  includes a hole  228  between the reservoir  226  and the pump flood area  230 . The bladder  224  can expand and contract with flow of hydraulic fluid into and out of the reservoir  226 . The cover  222  prevents the bladder  224  from being accidentally ruptured. 
     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.