Abstract:
The present invention discloses a workshop unit for use as a grinding center that includes a support frame having a drive motor and a multi-station tool mounted thereto. Particularly, the grinding center may be used for operations including but not limited to grinding, buffing, polishing, sanding, and cleaning. The multi-station tool includes a plurality of rotary tools, a power transfer system, and a rotary tool selecting system. The power transfer system operates through a plurality of pulleys each in communication with at least one rotary tool and the drive motor through a plurality of transmission links. The rotary tool selecting system, which includes one or more control shafts and a clutch system, allows each tool to be selectively and independently operated. The present invention provides a cost and space saving apparatus in which several tools share expensive components and are arranged within one unit to provide more functionality in less space relative to the same tools purchased and operated individually.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a workshop unit that includes a plurality of different tools mounted on a single frame. More specifically, this invention is directed to a center for rotary tools, such as grinding, buffing, polishing, and cleaning wheels. More particularly still, the invention relates to a center for rotary tools, any of which may be selectively operated at any time. 
   2. Description of the Related Art 
   Typically, rotary tool workshop units are designed for performing only one particular operation. This conventional design requires an operator to utilize separate workshop units to perform each different operation. 
   One known workshop grinder is a two wheel bench grinder. Typically such a grinder carries a grinding wheel mounted on one end of a rotating shaft and a buffing brush wheel mounted on the other end of that shaft. The types of wheels that can be mounted on the ends of the shaft vary and are interchangeable on the shaft. The shaft of the bench grinder is a single unit and, therefore, the output ends of the shaft are coupled such that they turn at the same speed when the motor is on. Such a bench grinder is shown in U.S. Pat. No. 5,525,095, which is incorporated in its entirety herein by reference. 
   In use, the aforementioned two wheel bench grinder must be affixed to some supported flat surface or floor stand and can only operate two wheels at a time. The two wheel bench grinder cannot support continuous operations, which require more than two types of grinding wheels. For example, operations, which require more than two types of grinding wheels, must be interrupted for wheel changes when using the two wheel bench grinder. Further, the two wheel bench grinder is only suited for one user at a time because both wheels are in close proximity to each other and because they are on the same shaft, making the wheels useable from only one side of the grinder. 
   While there are known different types of rotary tool workshop units, there is not a grinding center that is as versatile as the present invention, which permits a substantial number of different operations to be performed continuously at a central location. A grinding center wherein several tools share expensive components, such as a motor, frame, switches, and housing, can provide a significant cost benefit as opposed to using individual units for each desired operation. In particular, many small establishments with less operating space desire a tool that provides several functions within a relatively small amount of space. In addition, it would be advantageous to be able to operate a desired tool without interference from other tools. 
   There is a need, therefore, for a more versatile rotary workshop unit that includes a plurality of rotary tools and allows the tools to be utilized selectively. 
   SUMMARY OF THE INVENTION 
   The present invention provides a workshop unit that includes a plurality of different tools mounted on a single frame. According to the present invention, any of the tools may be selectively operated at any time. The workshop unit first comprises a support structure. The support structure supports a multi-station tool having a plurality of rotating out-drives. The workshop unit also includes a drive motor supported on the support structure. The drive motor serves to selectively drive the plurality of out-drives. 
   In one embodiment of the present invention, the multi-station tool comprises a plurality of rotating out-drives and a drive motor. The multi-station tool has a power transfer system to deliver power to the plurality of rotating out-drives. The power transfer system includes a plurality of pulleys, wherein each pulley is disposed on at least one rotating out-drive, and a plurality of transmission links, wherein the plurality of transmission links places each pulley in communication with the drive motor and at least one other pulley. The multi-station tool also includes an out-drive selecting system. The out-drive selecting system includes a plurality of clutches, a plurality of cam followers, one or more control shafts, and a plurality of cams disposed on the one or more control shafts and in communication with the plurality of cam followers. Rotation of the one or more control shafts orients the cams, which serve to pivot one or more of the plurality of cam followers to engage or disengage the plurality of clutches from their respective pulley. 
   A method for selectively operating a multi-station tool according to one embodiment of the present invention is also provided. The multi-station tool is operated by first providing a first and second rotary out-drive to the multi-station tool, wherein each of the first and second rotary drives is engaged to a first and second clutch, respectively. Rotation of one or more control shafts correspondingly rotates a plurality of cams disposed on the one or more control shafts. The plurality of cams function to selectively pivot a plurality of cam followers in communication with the first and second clutch. The first clutch is then disengaged from the first rotary out-drive. Power is delivered from a drive motor to a plurality of pulleys through a plurality of transmission links to actuate the second out-drive, wherein at least one pulley is in rotational communication with the second out-drive. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     So that the manner in which the above recited features of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the drawings that follow, i.e.,  FIGS. 1A–B ,  2 A–B,  3 ,  4 ,  5 ,  6 , and  7 . However,  FIGS. 1A–B ,  2 A–B,  3 ,  4 ,  5 ,  6 , and  7  illustrate only selected embodiments of the present invention and are not to be considered limiting of its scope. 
       FIGS. 1A–B  present schematic views of a rotary tool workshop unit according to one embodiment of the invention. 
       FIG. 2A  shows a partial cross-sectional view of a multi-station tool according to one embodiment of the invention. 
       FIG. 2B  illustrates an adjacent side, partial cross-sectional view of the multi-station tool according to the embodiment of the invention shown in  FIG. 2A . 
       FIG. 3  presents a partial cross-sectional view of a multi-station tool according to another embodiment of the invention. 
       FIG. 4  shows an adjacent side, partial cross-sectional view of the multi-station tool according to the embodiment of the invention shown in  FIG. 3 . 
       FIG. 5  provides a top, partial cross-sectional view of the multi-station tool portion of the grinding center according to one embodiment of the present invention. 
       FIG. 6  shows a partial cross-sectional view of the invention according to another embodiment. 
       FIG. 7  provides top schematic view of the rotary shafts  22 ′ and  22 ″ according to yet another embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1A and 1B  illustrate one embodiment of the rotary tool workshop unit of the present invention. More particularly,  FIGS. 1A and 1B  show a grinding center from a first side and a second side, respectively. The grinding center first includes a support frame  1  having a drive motor  2  and a multi-station tool  3  mounted thereto. 
   Referring to  FIGS. 1A and 1B , the support frame  1  consists of four vertically extending support members or legs  54 , a cross member  12 , and a top plate  16 . The legs  54  are preferably fabricated from tubing having a square cross section. The cross member  12  may be fabricated from a single plate which has been cut and bent to form an open sided box and that cross member  12  is then attached in a substantially horizontal position between the four legs  54  such that a largest surface  5  of the support member is upwardly facing. Optionally, a sliding tool drawer (not shown) may be positioned within the cross member  12  for storing rotating tools or hand tools. The drive motor  2  is mounted to the largest surface  5  of the cross member  12 . Placement of the drive motor  2  below the multi-station tool  3  greatly increases the stability and reduces the vibration of the multi-station tool  3 . The top plate  16  may be fabricated in a manner similar to that of the cross member  12 . The top plate  16  is attached to the upper ends of the legs  54  and forms an upper surface  17  of the support frame  1 . Wheels  61  are fixed to the lower ends of two adjacent legs  54  by any suitable means, and adjustable pads  4  are fixed to the lower ends of the other two adjacent legs  54 . That arrangement allows a user to selectively relocate the grinding center by tilting it such that the pads  4  are removed from frictional contact with a surface on which the grinding center rests and then rolling the wheels  61  along that surface thereby moving the grinding center. When the grinding center has been rolled to a desired location, it can be set down such that the pads  4  are in frictional contact with the surface beneath the grinding center thereby fixing the grinding center at the desired location. 
   The multi-station tool  3  is mounted on the upper surface  17  of the support frame  1  and includes three rotary tool stations facing the first side of the grinding station and three other rotary tool stations facing the second side of the grinding station. The multi-station tool  3  receives power from the drive motor  2  via a drive link  18 . The drive link  18  is typically a v-belt but may be any suitable power transmission means. 
     FIG. 1A  is a schematic view of the first side of the grinding station. The three rotary tool stations facing that side are shown to be equipped with rotating disk tools  7 ,  6 , and  11 , where those tools rotate on shafts or out-drives having axes  9 ,  8 , and  15  respectively.  FIG. 1B  shows the second side of the grinding station. The three rotary tool stations facing that side are shown to be equipped with rotating disk tools  13  and  10  and belt sander  14 , where those tools rotate on shafts having axes  8 ,  9 , and  15 , respectively. The rotating disk tools may be any suitable disk tools such as grinders, buffers, polishers and the like. The belt sander  14  may also be any other suitable continuous belt or band tool or a flexible out-drive extension shaft for transmitting out-drive power to a location removed from the grinding center. Furthermore, any of the rotary tool stations may be equipped with any of the aforementioned tools or extensions or any other suitable rotary driven tool. 
     FIG. 2A  illustrates a partial cross-sectional view of the internal power transfer system or transmission system of the multi-station tool  3  according to one embodiment of the present invention. A double v-belt pulley  26  is concentrically affixed to the shaft having axis  15 , and single v-belt pulleys  34  (not shown) and  27  are concentrically affixed to the shafts having axes  8  and  9 , respectively. The diameter of each pulley  26 ,  27 , and  34  can be individually designed so that their respective shaft rotates at an optimal speed for their particular application. The drive link  18  is moved by a v-belt pulley  28  affixed to the output shaft of drive motor  2 . The drive link  18  transmits power from the drive motor  2  to the shaft  15  through the double v-belt pulley  26 . A transmission link  19  connects the shafts having axes  8 ,  9  and  15  through their respective pulleys. The transmission link  19  is moved by the double v-belt pulley  26  and thereby transmits power to the shafts having axes  8  and  9  via single v-belt pulleys  34  and  27 , respectively. Shafts having axes  8 ,  9  and  15  are supported by a plurality of bearings  24  contained within the housing  25 . 
     FIG. 2B  shows an adjacent side, partial cross-sectional view of the grinding center with the multi-station tool  3  according to the embodiment of the invention illustrated in  FIG. 2A . In the perspective of  FIG. 2B , the transmission link  19  is shown in communication with three shafts  20 ,  21 , and  22  disposed on axes  8 ,  9 , and  15 , respectively. The tension on the transmission link  19  is maintained at a desired level by an idler pulley  23 . The desired tension in transmission link  19  and therefore the corresponding percentage of power transmitted to the shafts  20  and  21  from the double v-belt pulley  26  is adjustable by altering the interference of idler pulley  23  in the path of transmission link  19 . As shown in  FIG. 2B , the multi-station tool  3  has a rotary shaft or tool selection system that includes multiple control members,  41  and  42 , which act to engage or disengage a respective clutch thereby activating or deactivating the desired shaft. The control members  41  and  42  shown as hand levers in  FIG. 2B  may also be dials or any other control member known by a person of ordinary skill in the art. A third control member (not shown) is hidden by control member  41  in the view of  FIG. 2B . In this particular embodiment, each control member controls only one clutch, thereby actuating the rotation of only one shaft. In this particular embodiment of the invention, both rotary tools disposed on each shaft  20 ,  21 , and  22  operate dependently and therefore, upon actuation of the desired shaft both tools in communication with the desired shaft will be actuated. However, each shaft  20 ,  21 , and  22  can be split into two independent shafts and a double clutch system can be utilized to independently operate each rotary tool. 
   In one embodiment of the invention, the clutches may be designed to disengage or slip at a predetermined torque that is below the torque level that will cause the motor to burn out or stall. However, it may be desirable depending on the particular use of the grinding center to configure the clutches to disengage or slip at a torque above the torque level that will cause the motor to burn out or stall. This will allow the maximum possible torque output of the motor to be delivered to the rotary shafts. 
   As an added safety feature, micro switches (not shown) may be incorporated within the control member and clutch assemblies to prevent the motor  2  from being actuated in the event that more than one clutch has been placed in an actuated position. The micro switches decrease the likelihood of motor overload due to more than one shaft being operated concurrently. 
     FIGS. 3–5  illustrate another embodiment of the present invention.  FIG. 3  illustrates a partial cross-sectional view of the rotary shaft or tool selection system of the multi-station tool  3 . As shown in  FIG. 3 , only one control member  29  is provided to operate a centrally disposed control shaft  30 . Although in  FIG. 3 , the control member  29  shown is a dial, it is understood that the control member  29  could also be a lever or any other type of control member known by a person of ordinary skill in the art. The control shaft  30  includes a plurality of cams  56  disposed along the length of the shaft  30 . Each cam  56  interacts with a unique cam follower  70 ,  71 ,  72  or  73  as presented in  FIG. 3 . Cam followers  72  and  73 , which interact with the clutch systems that control the upper shafts  20  and  21 , respectively, are not shown in the perspective of  FIG. 3  and will be shown and described in more detail with reference to  FIG. 5 . The control member  29  and control shaft  30  may be designed such that the control member  29  will include a directional marking oriented towards the tool or shaft desired for activation. In another embodiment, the control member  29  can be in the form of a lever and extend in the direction of the tool or shaft desired for activation. Positioning the control member  29  at the top of the housing  25  allows for easy access by the operator from all sides of grinding center. 
   Referring again to  FIG. 3 , the lower rotating shaft is manufactured from two independent shafts  22 ′ and  22 ″, wherein each shaft  22 ′ and  22 ″ can rotate independently from each other, thereby allowing the tools disposed on the axis  15  to operate independently from each other. The double v-belt pulley  26  is disposed around a junction  75  where the shafts  22 ′ and  22 ″ are joined together. The double v-belt pulley  26  is positioned between two clutches  50  and  51 . The clutches  50  and  51  are normally biased in an engaged position against the junction  75  and thereby against the double v-belt pulley  26  by the use of one or more compression springs  58 . By rotating the control member  29  the cams  56  positioned on the control shaft  30  can be oriented to disengage or engage the clutches  50 ,  51 ,  52 , and  53 . 
   As shown in  FIG. 3 , the clutch  51  is disengaged from the double v-belt pulley  26  as evident by the gap  33  between the clutch  51  and the double v-belt pulley  26 . In this position, the cam follower  71  pushes the clutch  51  away from the pulley  26  thereby disengaging it and preventing rotation of the shaft  22 ″. On the opposite side of the pulley  26 , the clutch  50  is in an engaged position with the junction  75  and the double v-belt pulley  26 . Since the cam follower&#39;s  70  respective cam  56  is not oriented in a position to angle the cam follower  70  against the clutch face  32 , the clutch is maintained in an engaged position by the bias imparted on the clutch  50  by the spring  58 . The clutch faces can be substantially planar, as shown for simplicity, or cone shaped. A cone shaped clutch face design will create a greater clutch face interface force as a result of the axial spring force between the clutch members. A large enough clutch interface force will alleviate the need for a high friction material at the clutch interface. Therefore, using cone shaped clutches can potentially reduce the number of parts required and hence the manufacturing cost and complexity. 
   The control shaft  30  and the cams  56  can be designed to allow several tools to operate simultaneously or to allow only one tool to be operated at a time. As previously mentioned, allowing only one tool to operate at a time will minimize the possibility of motor overload and will also make the tool safer to use by preventing the unexpected actuation of a tool or tools that are not desired for use at that particular time. Conversely, the multi-station tool  3  can be designed for the use of multiple rotary tools simultaneously. This design may be desirable in a production or manufacturing environment where several operators are using the same multi-station tool. Accordingly, the motor  2  can be designed to handle a greater load resulting from the concurrent use of several rotary tools. 
   As illustrated in  FIG. 3 , the control member  29  includes a spring-loaded ball  31 . When an adequate axial force is conveyed to the control member  29 , the ball  31  will disengage from a groove located on the housing  25 . The control member  29  can then be rotated to the desired position wherein the ball will engage another groove provided on the housing  25 . The spring-loaded ball  31  allows the control member  29  to remain in the desired location during operation of the multi-station tool  3 . In addition, the spring-loaded ball prevents the inadvertent actuation of other tools during operation. In another embodiment of the invention, a mechanical linkage (not shown) interconnects the control shaft  30  or the control member  29  to the master power switch (not shown). Once the clutch corresponding to the selected tool or shaft is actuated and the master power switch is turned on, the mechanical linkage will move into a locking engagement with the control shaft  30  or the control member  29  to prevent the control shaft  30  or the control member  29  from rotating. This locking engagement will prevent the clutches from being coupled or decoupled during operation, which will minimize clutch wear due to clutch faces coming into contact with each other under differential rotary speeds. 
     FIG. 4  illustrates an adjacent side, partial cross-sectional view of the multi-station tool  3  according to the embodiment of the invention shown in  FIG. 3 . The perspective of the multi-station tool  3  in  FIG. 4  is similar to that of  FIG. 2B . However, as described with relation to  FIG. 3 , in this particular embodiment of the present invention, only one control shaft  30  is necessary to actuate the desired rotary tool or tools. The transmission link  19  is shown in communication with three shafts  20 ,  21 , and  22 ′, recalling that shaft  22 ″ (not shown in this perspective) shares the same axis  15  as shaft  22 ′. As in  FIG. 2B , the tension on the transmission link  19  is maintained at a desired level by an idler pulley  23 . 
     FIG. 5  is a top, partial cross-sectional view of the multi-station tool  3  portion of the grinding center according to one embodiment of the present invention.  FIG. 5  illustrates a clutch system that includes clutches  52  and  53  and their respective cam followers  72  and  73 . The transmission link  19  is shown to extend between the two top single v-belt pulleys  34  and  27 . As similarly described with respect to  FIG. 3 , the control shaft includes a plurality of cams  56 , which are oriented to interact with the top cam followers  72  and  73 . In  FIG. 5 , the clutch  53  has been disengaged by cam follower  73  as evident by the gap  35  between the single v-belt pulley  27  and the clutch  53 . Once the clutch  53  has been disengaged, rotational force cannot be transferred to the shaft  21  from the pulley  27 . The clutch  52  is shown in an engaged position wherein the shaft  20  is in rotational communication with the single v-belt pulley  34 . The shafts  20  and  21  may each be split in two parts as in shafts  22 ′ and  22 ″. This would allow independent control of the tools on either side of the shafts  20  and  21 . Accordingly, the addition of two cam followers and a double clutch system would be required for the tools on either shaft  20  or  21  to operate independently from each other under this design. 
   In one embodiment of the invention, the motor  2  is designed to vary its rotational direction based on which tool or shaft is activated. For example, the rotary tools on each shaft are typically designed to rotate towards their respective worktable. Accordingly, the direction of rotation of the shaft  20  will be opposite to that of shaft  21 . A switch system (not shown) is added to the control shaft  30  to communicate to the motor  2  the proper axial direction for rotation depending on which shaft is activated. Furthermore, if the control member is positioned in an intermediate location where no clutch is coupled, the switch system will prevent the motor from rotating. This design will ensure that a clutch is engaged before the motor is actuated thereby preventing clutch wear resulting from contact of the clutch faces under differential rotary speeds. 
     FIG. 6  is a partial cross-sectional view of the invention according to another embodiment. As shown in  FIG. 6 , a positioning device  77  is located adjacent to the lower axis  15 . The positioning device  77  is used to place the belt sander  14  in varying angular positions. The belt sander  14  will temporarily lock in to place at a desired location on the positioning device  77  so as to facilitate the operation of the belt sander  14  at varying angular positions.  FIG. 6  also illustrates the drive motor  2  disposed on an angled planar surface  79 . The surface  79  includes an elevation mechanism  78  disposed at one end. The elevation mechanism  78  serves to raise or lower the drive motor  2  thereby allowing the tension in the transmission link  18  to be decreased or increased as desired by the operator. 
     FIG. 7  is top schematic view of the rotary shafts  22 ′ and  22 ″ according to one embodiment of the present invention. As shown in  FIG. 7 , the rotary disk tool  11  includes a flexible shaft apparatus  80 . The flexible shaft apparatus  80  serves to increase the rotational velocity of the rotary tool  11  by means well known to a person of ordinary skill in the art. A handle  82  is used to actuate the flexible shaft apparatus  80 . The flex shaft apparatus  80  is shown in communication with the rotary tool  11 ; however, it is assumed that a flexible shaft apparatus can be placed in communication with any of the rotary disk tools disposed on the multi-station tool  3 .  FIG. 7  also shows a work table disposed below the rotary tool  11  to provide support to an object (not shown) during operation. 
   While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.