Abstract:
The torque wrench with quick release gear set is a system having a rotary actuator drive unit, which is attachable to a planetary drive gear set by a quick-release cylindrical adapter and collar so as to provide quick interchangeability of gear sets without the use of tools. The rotary actuator actuates the planetary gear set by means of a drive shaft connection through the quick-release cylindrical adaptor to engage a corresponding input gear drive shaft. The rotary actuator may have a pistol grip handle that rotates 360° to provide a user with an ergonomically friendly tool. The planetary gear set contains axial thrust bearings between each planet carrier to reduce friction and increase stability. The planet carriers are made of single piece construction to provide increased gear set durability. Precision radial bearings keep the planetary carriers and annulus concentric.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to power tools. More particularly, the present invention relates to a rotary actuated tool system having a single rotary actuator and quickly interchangeable planetary gear sets. 
     2. Description of the Related Art 
     The use of rotary operated torque wrenches is well known, particularly in the tightening large nuts on bolts or studs and in tight clearance installations not allowing for the travel of a long wrench handle. Japanese Patent No. 2-29,845, published Dec. 10, 1990, appears to only address the issue of compound movement actuation using both linear and rotary servomotors. 
     Thus, a torque wrench solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The present invention is a precision torque wrench system having a rotary actuator drive unit that is attachable to a planetary gear drive set by a quick-release cylindrical adaptor collar and a rotatable locking collar in order to provide a user-friendly attachment method. 
     The ring gear, i.e., annulus, is held securely and concentric to the rotary actuator, and movement in the axial direction is constrained. However, rotational movement is not constrained. 
     The rotary actuator may have a pistol grip handle that rotates 360°, thus providing better ergonomics for the user. 
     The rotary actuator actuates the planetary gear set by means of a motor drive shaft traveling and engaging a corresponding input gear drive shaft through the quick-release cylindrical adaptor collar. 
     The planetary gear set contains axial thrust bearings between each planet carrier to reduce friction and increase stability by providing a constraint from pivoting and to insure that the centerline of the carriers is always concentric and coincident to each other and also in relation to the centerline of the rotary actuator. The axial thrust bearings are pre-loaded by a Belleville washer that is located between the end cap and the top of the first stage carrier. 
     The planet carriers are made of single piece construction to provide increased gear set durability. Precision radial bearings keep the planetary carriers and annulus concentric. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an environmental, perspective view of a torque wrench with a quick release gear set according to the present invention. 
         FIG. 2A  is a perspective view of an actuator attachment system on a rotary actuator housing, depicting a quick change attachment flange according to the present invention. 
         FIG. 2B  is a perspective view of the actuator attachment system on the actuator housing, depicting actuator drive shaft and related components of a torque wrench with a quick release gear set according to the present invention. 
         FIG. 2C  is a top view of the quick change attachment flange of the present invention. 
         FIG. 3  is a perspective cut-away view of the actuator attachment system of a torque wrench with a quick release gear set according to the present invention, showing cam lobes on the lock collar. 
         FIG. 4A  is a perspective view of the gear set housing including gear set adapter collar. 
         FIG. 4B  is an exploded view of gear set adapter collar and gear set housing. 
         FIG. 4C  is a perspective cut-away view of adapter collar attachment for the rotary actuator of a torque wrench with a quick release gear set according to the present invention. 
         FIG. 5  is a perspective view of the annulus and gear set housing of a torque wrench with a quick release gear set according to the present invention. 
         FIG. 6  is an exploded perspective view of the gear set assembly of a torque wrench with a quick release gear set according to the present invention. 
         FIG. 7  is a perspective view of the first planet carrier of a torque wrench with a quick release gear set according to the present invention. 
       Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is a precision torque wrench system having a set of planetary gears driven by a rotary actuator. According to the present invention, as shown in environmental  FIG. 1 , the torque wrench with quick-release gear set  100  is made up of a hand held rotary actuator  103  with a pistol grip like feature P and a quickly interchangeable gear set  105  having a unitary construction reaction bar, such as bar  107 . The rotary actuator may be pneumatic, hydraulic, or electric. 
     According to the present invention, an actuator attachment system having the quick release feature of the torque tool  103  provides for quick and easy interchangeability with a set of planetary gears for various torque outputs. 
     As shown in  FIGS. 1 and 2A , a structure of the rotary actuator  103  comprises a quick change attachment flange  202  that is rigidly attached to or integrally a part of housing  203  of the rotary actuator  103 . The quick change attachment flange  202  includes a base  204 , a base inner circumference  230 , and a base outer circumference  232 . A substantially cylindrical inner periphery  206  having an inner dimension  234  and an outer dimension  236  extends perpendicularly from the base inner circumference  230  of flange base  204 . 
     As shown in  FIGS. 2A and 2C , the inner periphery  206  includes a plurality of through bores having a predetermined diameter, such as through bore  208 , which are directed along radial lines converging inward to an axial center line of the inner periphery  206 . Moreover, for each through bore  208 , inner periphery  206  has a corresponding counter bore  213  of a predetermined depth  242 , and having a greater diameter than through bore  208 . 
     In addition, disposed within each counter bore  213  is a compression spring  211 . The interface of counter bore  213  with through bore  208  creates a shoulder  240  that provides an axial support for compression spring  211 . 
     For each compression spring  211 , counter bore  213  and through bore  208  combination, an engagement pin, such as engagement pin  209  is disposed inside the compression spring  211 , counter bore  213  and through bore  208  combination so that when a head of the engagement pin  209  is depressed, the engagement pin  209  penetrates corresponding bore  208 . 
     Base  204  has a side component  218  with an elongated cavity  219  disposed perpendicular to the base outer circumference  232 . Inside and supported by elongated cavity  219  is a compression spring-loaded lock pin  220  having a lock pin lever  221 . Rotatable locking collar  222  rests on the base  204  and fits concentrically outside of and proximate to the inner periphery  206  of the quick change attachment flange  202 . The rotatable locking collar  222  has a lock slot  224 , i.e., cutout on the end of collar  222  that is resting atop base  204 . The lock slot  224  engages the lock pin  220  when the rotatable locking collar  222  is rotated to a locked position. 
     Moreover, as shown in  FIGS. 3 and 2C , rotatable locking collar  222  has a plurality of cam lobes, such as lobe  225  on an inner circumference of the collar  222 . Referring to  FIGS. 2C and 3 , note that the outer dimension  236  of the inner periphery  206  has a detent, i.e. stop control  226 , that defines a circumferential notch of inner periphery  206 . 
     Collar  222  has a stop control boss  228  that fits within detent  226  for the purpose of limiting the rotational freedom of the collar  222 . Thus, when the collar  222  is located to a first stop position, the cam lobes  225  depress the engagement pins  209  so that the pins penetrate the through bores  208  of the inner periphery  206 . When the collar  222  is counter-rotated to the other stop position, the compression spring-loaded engagement pins  209  retract from the inner periphery bores  208 . Moreover, as shown in  FIG. 2A , a ring-like, substantially cylindrical protective cover plate CP being disposed over cam lobes  225  and engagement pins  209  and being attached to the quick change attachment flange  202  extends outward from the inner dimension  234  of the inner periphery  206  to an outer circumference of the rotatable locking collar  222  to provide an axial constraint on the rotatable locking collar  222  so that the locking collar  222  remains rotatably attached to the flange base  204 . 
     As shown in  FIG. 4A , gear set  105  comprises an adapter collar  302  that has a groove, i.e., cylindrical axial channel C around a circumference of the adapter collar  302 .  FIG. 4B  more clearly shows how the adapter collar  302  also has a lip  306 , which is disposed proximate to and above the channel C. The lip  306  has a circumference that is sufficient to cause adapter collar  302  to be supported by cover plate CP, ( FIG. 2A ), when the channel C of adapter collar  302  is inserted concentrically inside of and proximate to the inner periphery  206 . On the other side of the lip  306  is a threaded cylindrical continuation  310  of the adapter collar  302 , which threads into the gear set housing H. 
     The adapter collar  302  is located at an actuator attachment end  304  of the gear set  105 . As shown in  FIGS. 2A and 4A  through  4 C, when the grooved portion, i.e., channel C, of the adapter collar  302  is inserted concentrically inside of and proximate to the inner periphery  206 , and rotatable collar  222  is rotated to cause cam lobes  225  to extend engagement pins  209  through bores  208 , and into the channel C, an axial lock of the rotary actuator  103  to the gear set  105  is achieved, while rotational freedom between the two is maintained. Thus, the gear set housing H and annulus  502  are attached securely, axially and concentric to the rotary actuator so as to lock an axial position while allowing rotation to provide rotational movement of the rotary actuator relative to the annulus or other gears of gear set  105 . 
     Additionally, lock slot  224  engages the lock pin  220  to insure that the axial lock of rotary actuator  103  to gear set  105  remains intact until the lock pin  220  is disengaged by depressing lock pin lever  221  so that lock pin  220  is free and clear of lock slot  224 . When the lock pin  220  is disengaged, a counter-rotation of rotatable collar  222  retracts the engagement pins  209  and allows the gear set  105  to be detached from the rotary actuator  103 . 
     As shown in  FIG. 4A , reaction bar  107  attaches to a workpiece engagement end  305  of gear set  105 , whereby the internal hexagonal shape of  107  fits over the male hexagonal shape of  305 . Reaction bar  105  is held in place and constrained axially with either a metallic snap ring, elastomeric O-ring, or a threaded nut. During workpiece engagement, the reaction bar  107  holds an annulus  502 , i.e., ring gear, (refer to  FIG. 5 ), of the gear set  105  stationary during tool operation in order to provide rotation of a sun gear such as gear  712 , ( FIG. 7 ), thus permitting transmission of torque from the rotary actuator to an output shaft, such as output shaft  713  of the planetary gear set. 
     Referring to  FIGS. 2B and 6 , note that rotary actuator drive shaft  210  comprises a radial slot  215  that, in the embodiment shown, traverses the entire diameter of the drive shaft  210 . However, radial slot  215  may traverse a pre-determined portion of the drive shaft  210  sufficient to transmit torque from the drive shaft  210 . As shown in  FIG. 6 , first stage input gear  608  of gear set  600 , comprises a first stage input gear shaft  605 , and a drive rotary actuator engagement boss  606 , which is an oval-like protrusion of first stage input gear shaft  605 . 
     As shown, the drive rotary actuator engagement boss freely protrudes through the central opening of adapter collar  302 . According to the present invention, the drive rotary actuator engagement boss  606  fits into the radial slot  215  of rotary actuator drive shaft  210  to provide mechanical coupling for torque transmission of the rotary actuator  103  to the gear set  600 . 
     Furthermore, a radial thrust bearing  602  fits over first stage input gear shaft  605 . Within the gear set housing H, and tightly sandwiched between the adapter collar  302 , and an input side of a first planet carrier  612  is a compression member, e.g., in the embodiment shown, the compression member is a Belleville washer  604 . Note that gear set side  628  of adapter collar  302  functions as a gear set end cap when adapter collar  302  is threaded into gear set housing H. 
     Optionally, the configuration of the Belleville washer  604  and the first stage planet carrier  612  includes an axial thrust bearing  610  sandwiched between the Belleville washer and the first stage planet carrier  612 , where the axial thrust bearing  610  is radially held into place by being placed over a radial bearing hub  706 , (see  FIG. 7 ), of the first planet carrier  61   2 . First planet carrier  612  and the entire gear set  600  are axially preloaded by the Belleville washer  604  to reduce axial play and thus mitigate gear set wear and tear. 
     Preferably, in addition to first planet carrier  612 , at least one additional planet carrier axially in line with the first planet carrier  612  is configured to receive torque from the output of first planet carrier  612 . The additional planet carrier, such as second planet carrier  624  has an output side comprising an axial thrust bearing hub, like hub  708 , and an axial thrust bearing  610  attached to the axial thrust bearing hub, such as hub  708 . 
     All planet carriers of the gear set  600 , including first planet carrier  612 , are of a unitary, i.e., one-piece construction. Referring to  FIGS. 6 and 7 , it is shown that the present invention provides for a unitary construction of planet carrier  612  comprising a first circular flange shaped member  680  having a radial bearing hub  706  for receiving a radial bearing, such as radial bearing  622 . 
     Furthermore, the first circular flange member  680  has an axial opening  681  for receiving a previous stage sun gear or actuator drive gear such as gear  608 . As shown, the radial bearing hub  706  is axially directed towards a previous stage of the gear set  600 . The first circular flanged shape member  680  is integrally, i.e., unitarily connected by a plurality of spacing members, such as spacing member  682  to a second circular flange shaped member  684 . 
     The second circular flange shaped member  684  forms an axial thrust bearing hub  708 , which is directed axially towards a following stage of the gear set. An output shaft  713 , including a sun gear  712  and sun gear axle hub  714  is integrally connected axially to the second circular flange shaped member  684 , as shown in  FIG. 7 . Second circular flange shaped member  684  also has an axially positioned C-bore for receiving a previous stage sun gear such as sun gear  712 , and sun gear axle hub, such as sun gear axle hub  714 . A plurality of planet gear pockets, such as planet gear pocket  702  are formed by the integral, unitary connections between the plurality of spacing members, such as spacing member  682 , and the first and second circular flange shaped members  680 ,  684 . 
     As shown, planet gear axle borings, such as planet gear axle boring  704 , are made in the first circular flange shaped member  680  and the second circular flange shaped member  684  corresponding to and centered about each of the planet gear pockets, such as planet gear pocket  702 , for holding the plurality of planet gears of each planet carrier, such as first planet carrier  612 , second planet carrier  624  and third planet carrier  626 . 
     The unitary construction of the planet carriers, such as planet carrier  612 , further reduces wear and tear of the gear set by limiting both radial and axial play. Additionally, the unitary construction of carrier  612  provides for a more durable tool, eliminating the need for several individual bolted on carrier components. Planet gears  618  fit in the planet gear pockets  702  of planet carriers, such as planet carrier  612 , and may optionally be axially sandwiched by planet gear washers  620 . 
     Additionally, the planet gears  618  are supported radially by precision radial bearings, such as bearing  616 . Planet gear axle  614  is inserted through the planet axle boring  704  to support the assembly of washers  620 , planet gear  618  and bearing  616  within the planet gear pocket  702 . According to the present invention, for each planet carrier  612 , the planet gear axles, such as planet gear axle  614 , are held in place axially by the two axial thrust bearings  610 , as shown in  FIG. 6 . 
     The present invention provides for a last stage of the planet carriers, such as, in the embodiment shown, planet carrier  626 , having a workpiece engagement shaft  627  in lieu of planet gear  712 . In the embodiment shown, workpiece engagement shaft  627  has a square configuration; however it should be understood that workpiece engagement shaft  627  may have a variety of structural configurations including a spline, hex, square, or any other configuration suitable to engage the workpiece at hand. 
     To maintain a centerline of the planet carriers, such as carrier  612 , each carrier is fitted with a precision radial thrust bearing, such as planet gear radial bearing  611  over planet gear radial bearing hub  706 . Fitting over and concentric to radial bearing  611  is radial bearing sleeve  615 . The precision radial bearings, such as radial bearing  611 , keep the annulus and planetary carriers concentric. The output stage of the planet carrier is fitted with an axial thrust bearing, such as axial thrust bearing  610 , over axial thrust bearing hub  708  to reduce friction and increase stability of the gear set  105 . 
     The torque output of the present invention is directly proportional to an input air pressure and flow. Regulation of the air pressure introduced into an actuator having a pneumatic rotor controls the torque output of the tool. A torque wrench of the present invention is calibrated on a certified test device to produce a cross reference chart for determining a required input air pressure for a desired torque output. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.