Abstract:
A flexible hydraulic vise that is actuated hydraulically along the entire length of the jaw travel. The vise includes master jaws disposed in a complementary shaped tracks, connected to pistons by pins. Top jaws with spring loaded ball detents are secured to the master jaws by a dove-tail notch connection. Internal passageways allow pressure to be delivered to either side of pairs of the pistons disposed in the bores, allowing the clamping force to be exerted inwardly or outwardly.

Description:
This application claims priority of U.S. Provisional Patent Application Ser. No. 60/086,609, filed on May 22, 1998, the disclosure of which is incorporated herein by reference. 

   TECHNICAL FIELD 
   The present invention relates generally to vises, and is particularly directed to a hydraulic vise. The invention will be specifically disclosed in connection with a hydraulic vise having up to four working faces and in which the jaws are hydraulically actuated through out their full stroke of travel. 
   BACKGROUND OF THE INVENTION 
   Vice systems and clamping systems are well known, including one or more movable jaws which are positioned to secure a workpiece in place. Workpieces may be held between movable jaws and fixed jaws, or just between movable jaws. Vises are frequently carried by pallets which are shuttled into the appropriate position for machining. In such applications, while parts on one pallet are being machined, finished parts can be unloaded and unfinished parts loaded on vises carried by other pallets. 
   Most prior art vises utilize a mechanically driven mechanism, such as a screw, either alone or in conjunction with hydraulic actuation. In use, the mechanical mechanism advances the one or more movable jaws to a position proximal to the workpiece. For a mechanical system, the mechanical mechanism provides the entire clamping force, whereas in a combination system, the jaws are hydraulically advanced the last portion of their stroke to contact and secure the workpiece in place. 
   Mechanical systems increase the time required to load parts and are difficult to automate economically. Obtaining accurate and repeatable clamping forces and accurate positioning with mechanical systems can be difficult. While combination mechanical/hydraulic systems can be better than purely mechanical systems, they still suffer many of the same drawbacks. 
   Additionally, significant impacts can be exerted on the part by the cutting tool, giving rise to the possibility that the workpiece may shift, causing reject parts, or allow the part to be “caught” by the cutting tool and ripped out of the vise. It is possible for a caught part to be forcefully thrown from the vise and cause injury. If aluminum or other soft material top jaws are used, impacts delivered to the workpiece and transmitted to the jaws can result in deforming the jaws and allowing the part to become loose. To overcome this, mechanical vises have to be mechanically adjusted, such as by the operator, to take up the slack. A hydraulic vise can take up the slack, making the use of aluminum jaws much safer. 
   There is a need in the art for a vise which is fully hydraulic, which allows the operation of the vise to be automated. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to obviate the above-described problems and shortcomings of the prior art heretofore available. 
   It is another object of the present invention to provide a hydraulic vise which is fully hydraulic. 
   It is yet another object of the present invention to provide a hydraulic vise in which the entire travel of the movable jaws is hydraulically actuated. 
   It is another object of the present invention to provide a vise in which the clamping direction can be easily reversed. 
   It is another object of the present invention to provide a vise which reduces or eliminates the above identified dangers with jaws made of a soft malleable material such as aluminum. 
   Additional objects, advantages and other novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
   To achieve the foregoing and other objects, and in accordance with the purposes of the present invention as described herein, there is provided a vise comprising a body with one or more internal bores, with each bore having one or more pistons disposed therein. Each piston is connected to a respective master jaw which is slidabley carried in a jaw track formed in or disposed adjacent a face of the vise body. The piston and master jaw move concomitantly. The master jaw carries a top jaw, or an alternative workpiece holder, such that workpieces or the workpiece holder may be securely held in place. The movement of the master jaw is accomplished hydraulically rather than using a mechanical mechanism. 
   In accordance with another aspect of the present invention, the piston may include an accumulator. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings: 
       FIG. 1  is an exploded perspective view of a hydraulic vise in accordance with the present invention. 
       FIG. 1A  is an exploded assembly view illustrating the connection between the piston, link pin and master jaw. 
       FIG. 1B  illustrates the top jaw. 
       FIG. 2  is an end view of a vise body constructed in accordance with the present invention. 
       FIG. 3  is a cross sectional view of the vise body taken along line  3 — 3  of  FIG. 2 . 
       FIG. 4  is a top view of the vise body of  FIG. 2 . 
       FIG. 5  is an end view of a master jaw. 
       FIG. 6  is a side view of a master jaw. 
       FIG. 7  is a top view of a master jaw. 
       FIG. 8  is a bottom view of a master jaw. 
       FIG. 9  is a cross-sectional view of a top jaw taken along its midline. 
       FIG. 10  is a top view of the top jaw. 
       FIG. 11  is a schematic diagram of the hydraulic circuit of a hydraulic vise constructed in accordance with the present invention. 
       FIG. 12  is an enlarged, diagrammatic, fragmentary view of an accumulator disposed in a piston. 
       FIG. 13  is an end view of an alternative embodiment of the present invention. 
       FIG. 14  is a cross-sectional view of the alternate embodiment taken along line  14 — 14  of  FIG. 13 . 
       FIG. 15  is a view similar to  FIG. 14  showing a fixed jaw in the center, and illustrating some of the internal passageways. 
       FIG. 16  is a top view of the vise of  FIG. 13 . 
       FIG. 17  is a bottom view of the vise of  FIG. 13 . 
   

   Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the drawings in detail, wherein like numerals indicate the same elements throughout the views,  FIG. 1  is an exploded view of a vise constructed in accordance with the present invention. The hydraulic vise, generally indicated by the numeral  2 , includes body  4 , preferably, but not necessarily made of one piece. Body  4  includes four faces,  6   a ,  6   b ,  6   c  and  6   d . As described below, the vise may have only one face, or any number of faces which are appropriate for the application, for example five, six or more faces. As can also be seen in  FIGS. 2 and 3 , each face  6   a–d  has an associated bore  8   a ,  8   b ,  8   c  and  8   d . For simplicity of explanation, since the construction a of each face  6   a–d  and bore  8   a – 8   d  are the same, only one face and associated bore will be in detail, it being understood that the description applies to all four faces. 
   Bore  8   a  includes pistons  10   a  &amp;  12   a  disposed therein. The diameter of pistons  10   a  &amp;  12   a  depend on the clamping loads desired in conjunction with the hydraulic pressure. In one embodiment the piston has a nominal diameter of 2 inches. Each piston  10   a  and  12   a  has an O-ring  14  disposed in an O-ring groove at either end of the piston  10   a  and  12   a , forming a seal with bore  8   a . Other suitable seals may also be used, whether carried by piston  10   a  or  12   a , or fixed within bore  8   a . Bore  8   a  is sealed at both ends by end caps  16   a . End caps  16   a  may be threaded caps with O-ring seals, although any suitable seal will work. Although two pistons per bore are depicted herein, it will be appreciated that many teachings of this invention may be used wherein single or more than two pistons per bore are used. 
   Each piston  10   a ,  12   a , has an associated master jaw  18   a  and  20   a  disposed within a jaw track or way  22   a  formed in face  4   a . The surface of jaw track  22   a  may be hardened to improve its wear characteristics. In one embodiment, body  4  was made of 1045 steel and flame hardened. Flame hardening is economical and results in less distortion than other heat treatments. 
   The construction of each master jaw is the same. As visible in  FIG. 2 , jaw track  22   a  is shaped complementarily to master jaw  18   a  and  20   a  to permit the master jaws to slide freely therein. Master jaw  18   a  includes two outwardly depending legs  19   a  which track  22   a  wraps around, retaining master jaw  18   a  therein. An alternative leg construction is depicted in  FIG. 5 . Any master jaw/jaw track configuration which permits the master jaw to slide freely while retained by the jaw track may be used. 
   Referring to  FIGS. 5–8 , master jaw  18   a  includes dove-tail  24   a  extending upwardly, disposed transverse to the longitudinal axis of jaw track  22   a , which is the axis of travel of master jaw  18   a  within jaw track  22   a . Master jaw  18   a  includes bore  26   a  with internal ring groove  28   a.    
   As can be seen in  FIG. 1A  and  FIG. 3 , master jaw  18   a  is connected to piston by pin  30  disposed within bore  26   a . Pin  30  is a ¾ inch diameter hardened steel pin. To assemble the piston, pin and master jaw together, piston  10   a  is disposed within bore  8   a  with bore  26   a  aligned with bore  34   a  of piston  10   a  through opening  32  formed in jaw track  22   a . Pin  30  is inserted into bores  26   a  and  34   a  having a snug fit. Internal circlip  36  is disposed in groove  28   a  to ensure pin  30  does not work its way out. In order to remove pin  30  for disassembly, a tapped hole (not shown) is formed in the exposed end of pin  30 . 
   Opening  32  limits the travel of piston  10   a  due to pin  30  extending therethrough. The size and location of opening  32  must not allow O-rings  14  to travel across opening  32  which would result in leaking hydraulic fluid out opening  32  and a corresponding drop in pressure. In one embodiment, opening  32  allowed a 2¾ inch for piston  10   a.    
   As shown in  FIG. 3 , master jaw  18   a  carries top jaw  38   a .  FIGS. 9 and 10  illustrate top jaw  38   a , which includes dove-tail notch  40   a  which is sized complementary to dove-tail  24   a . Top jaw  38   a  includes a spring loaded ball detent  42   a  disposed within a bore formed in top jaw  38   a . Spring loaded ball detent engages one of notches  44   a  in dove tail  24   a  with enough force to prevent top jaw  38   a  from sliding along dove-tail  24   a  while in use. As seen in  FIG. 7 , dove tail  24   a  has notches  44   a  on opposite sides. This allows the orientation of top jaw  38   a  to be reversed with respect to master jaw  18   a . As can be seen in  FIGS. 9 and 10 , dove-tail notch  40   a  is not on the center line of top jaw  38   a . This construction provides flexibility in conjunction with the dual action of the pistons, as described below. 
   The use of the dove-tail connection between master jaw  18   a  and top jaw  38   a  forces top jaw  38   a  downwardly when it exerts a clamping force on the work piece. It also allows the top jaw to be changed quickly via the snap on configuration. Other connections between top jaw  38   a  and master jaw  18   a  may be used. 
   Top jaw  38  may be configured to have another jaw attached to it, such as is depicted by threaded holes  39  shown in  FIG. 1B . 
   Referring to  FIG. 3 , vise  2  includes fixed jaw  48   a  securely attached to face  6   a , located thereon by dowel pins (not shown) and secured thereto by bolts (not shown). Each face  6   a–d  may have one or more fixed jaws against which each top jaw pair may clamp.  FIG. 3  illustrates two positions at which dead jaws may be disposed. Fixed jaw  48   a  is disposed adjacent one end of vise  2  on face  6   a . Another fixed jaw (not shown) could be disposed adjacent the opposite end of vise  2  on face  6   a . In this configuration, the top jaws (and associated master jaws and pistons) are urged outwardly from the center of vise  2  to clamp workpieces against the fixed jaws at either end. On face  6   c , fixed jaw  48   c  is shown disposed in the center of vise  2 . In this configuration, the top jaws (and associated master jaws and pistons) are urged inwardly from the center of vise  2  to clamp workpieces against the fixed jaw in the middle. Alternatively, the fixed jaw may be omitted and a workpiece clamped between two top jaws. Also, a tooling plate (not shown) carrying workpieces may be secured to vise  2  through dove tail notches formed in the tooling plate to be carried by the master jaws. The position of fixed jaws, or their absence, may vary from face to face. 
   Referring to  FIG. 11 , a schematic diagram of hydraulic circuit  48  for one bore of vise  2  is depicted. Each bore has a similarly plumbed, separately operable hydraulic circuit. Hydraulic circuit includes a source of pressurized hydraulic fluid (such as a pump), indicated by P, and a return to tank (or reservoir) line, indicated by T. The pressure would typically be set manually by the operator at the source pump. Check valve  50  is located in the pressurized side P upstream of valve  52   a . Valve  52   a  includes two positions which either directs the pressurized fluid to the outside cavities  54   a  and  56   a  of bore  8   a  and the return from interior cavity  58   a  to tank T, or directs the pressurized fluid to interior cavity  58   a  and the return from outside cavities  54   a  and  56   a  to tank T. When outside cavities  54   a  and  56   a  are pressurized, the associated master jaws and top jaws are urged inwardly toward each other. When inside cavity  58   a  is pressurized, the associated master jaws and top jaws are urged outwardly. Valve  52   a  may be left in between its two positions, sealing the pressure and holding the jaws in position exerting a clamping force as desired. Check valve  50  prevents a reduction in pressure in the vise side of the circuit in the event that valve  52   a  is left in either of its two positions. 
   Loss of even a slight amount of hydraulic fluid from the pressurized side of the clamps can greatly reduce the pressure and concomitantly the clamping force. Therefor, an accumulator may be incorporated in the hydraulic circuit. Referring to  FIG. 12 , an accumulator  60  is diagrammatically shown disposed in bore  62  in an end of piston  10   a . Accumulator  60  includes a series of Belleville washers  64  and piston  66  with O-ring  68  disposed in bore  62 . Internal ring  70  retains accumulator in bore  62 . Although each end of each piston may have an accumulator formed therein, it is not necessary as it adds cost. Preferably, an accumulator is included in either or both outside cavities  54   a  and  56   a , and in interior cavity  58   a . This provides accumulation to the pressure side regardless of the position of valve  52   a.    
   Referring to  FIG. 1 , vise  2  may be rotatably supported so as to permit each face  6   a–d  to be rotated into an appropriate position so workpieces on each face  6   a–d  may be operated on, such as being machined. In the configuration shown, end  2   a  of vise  2  is supported by fourth axis indexer  72 . Indexer  72  is controlled, for example, by the machining center to rotate vise  2  to the desired positions. The other end  2   b  of vise  2  is connected to tail stock  74 , such as is described in inventor&#39;s copending patent application Ser. No. 08/970,362, filed Nov. 14, 1997 for Tail Stock Mechanism, the disclosure of which is incorporated herein by reference. Tail stock  74  includes the source of pressurized hydraulic fluid which is delivered to vise  2  through ports in end  2   b  which lead to the respective outside and interior cavities. Tail stock  74  includes valves  76   a–d  (two shown in  FIG. 1 ), which correspond to valves  52   a–d  of the hydraulic circuit depicted in  FIG. 11 . Alternatively, the hydraulic connection may be provided independent of tail stock  74 . 
   Vise  2  may have 4 clamping faces as shown in  FIG. 1 , or may have more or less: Vise  2  may be one sided, two sided, three sided, five sided, six sided, etc. Referring to  FIGS. 13–17 , vise  78  is depicted as one sided, usable, for example, on any machining center, drill press, milling machine, etc. They can be stacked next to each other so that internal hydraulic porting can become like a built in manifold from vise to vise through a nipple O-ring sealed to each vise, with the vises bolted next to each other on the machine tool table. Vises can also be bolted on tombstone blocks mounted on pallets. The uses are basically limitless, and the number of faces depends on the requirements of the particular use. The construction is the same as depicted herein for the four sided vise  2 , and will not be discussed in detail. As shown in  FIG. 13 , vise  78  includes a valve mounting face  80  to which the control valve (not shown) would be attached. A pressure gauge  82  may also be included. Since vise  78  has a single face, there typically would not be a reason for it to be mounted rotatably, and therefor it would most likely not be mounted to tail stock  74 . In such a case, vise  78  would have a built-in control valve and pressure gage. 
   In summary, numerous benefits have been described which result form employing the concepts of the invention. The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described in order to best illustrate the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.