Abstract:
A governor mechanism is mounted for rotation with a drive shaft about an axis, has one or more reaction nozzles for imparting rotational movement to the drive shaft, and one or more valve portions supported for radially directed sliding movement between first and second radially spaced positions for purposes of controlling flow of pressurized fluid to the nozzles and thus the rotational speed of the drive shaft. The valve portions are formed integrally with a ring-shaped mounting portion fabricated from resiliently deformable material. In alternative constructions, similar governor mechanisms are co-axially mounted with vane motors by a common drive shaft and the mechanisms employed to control flow of pressurized fluid to the vane motor.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to a governor mechanism for controlling the rotational speed of a rotary device by a centrifugally operated valve means adapted to vary flow of pressurized fluid passing through the governor mechanism. Representation of prior art relating to this general type of mechanism include U.S. Pat. Nos. 444,938; 3,733,143; 4,087,198; 4,776,752; 5,496,173; and 5,567,154. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a governor mechanism adapted in the first instance for use in effecting rotation of a drive shaft in response to the discharge of pressurized fluid from the mechanism through one or more reaction nozzles, wherein flow of fluid to the nozzles is controlled by a resiliently deformable member having at least one valve portion carried by a ring-shaped mounting portion and supported by a guide for radially directed sliding movements in response to changes in the rotational speed of the drive shaft. 
     In alternative embodiments, the governor is co-axially mounted on a drive shaft with a fluid operated, vane-type drive motor, and the resiliently deformable member is employed to control the flow of pressurized fluid employed to operate the motor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The nature and mode of operation of the present invention will now be more fully described in the following detailed description taken with the accompanying drawings wherein: 
     FIG. 1 is a partial sectional view taken lengthwise through a rotary grinder device incorporating a governor mechanism of the present invention; 
     FIG. 2 is an enlarged view taken generally along the line  2 — 2  in FIG. 1; 
     FIG. 3 is an enlarged sectional view taken generally along the line  3 — 3  in FIG. 1; 
     FIG. 4 is a view similar to FIG. 3, but showing the second member of the mechanism deformed in response to the rotational speed of the mechanism; 
     FIG. 5 is a reduced size sectional view taken generally along the line  5 — 5  in FIG. 2; 
     FIG. 6 is a partial sectional view taken lengthwise through a rotary device of alternative construction; and 
     FIG. 7 is a partial sectional view taken lengthwise through a rotary device of a further alternative construction. 
    
    
     DETAILED DESCRIPTION 
     Reference is first made to FIG. 1, wherein a rotary grinder device is generally designated as  10  and shown for purposes of illustration as including an elongated, hand manipulated housing  12  enclosing an elongated drive shaft  14  supported therein by bearings  16 , 16  and having a first end  14   a  coupled to a chuck collet  18  for mounting a suitable tool, not shown, and a second end  14   b  coupled to a turbine device  20 , which serves to drive the shaft for rotation about its axis  22  in response to the supply of a fluid, such as air, under pressure to the turbine device from a suitable source, also not shown, via a suitable hose or tube  24  and a flow path  26  defined by communicating axially and radially extending openings  28  and  30  formed in the second end of the shaft. Typically, device would be fitted with a muffler  32  to reduce the noise of fluid passing from turbine device to the atmosphere via housing exhaust openings  34 . 
     In accordance with a presently preferred form of the present invention, turbine device  20  is designed to function as a governor mechanism serving to control the flow of fluid therethrough in order to limit the rotational speed of shaft  14 . 
     The present governor mechanism is best shown in FIGS. 1-5 as generally including a first member  36 , which serves to define discharge openings  38  shaped to define reaction nozzles through which pressurized fluid is expelled tangentially of shaft  14  for purposes of imparting rotation to the shaft and a passageway  40  serving to place the nozzles in flow communication with flow path  26 , and a second member  42 , which is resiliently deformable in response to change in the rotational speed of the shaft for purposes of varying the flow of fluid to the nozzles in order to limit the rotational speed of the shaft. 
     More specifically, first member  36  is of multi-part construction including a housing  44  defined by first and second outer end parts  46  and  48  and a third part  50  sandwiched therebetween. 
     First end or turbine base part  46  is of washer-shaped configuration sized to slidably receive shaft end  14   b , arranged to axially abut against a radially extending enlargement or abutment  52  carried by the shaft, and formed with an annular mounting member or flange  54  adapted to radially position or locate third part  50  concentrically of axis  22 , as best shown in FIGS. 1,  2 ,  4  and  5 . 
     Second or top plate part  48  is generally of washer-shaped configuration having locating notches  58 , 58  for use in keying third part  50  for rotation therewith and an enlarged hub  60  threadably engaged with shaft second end  14   b , as at  62 , for purposes of cooperating with abutment  52  to releasably clamp the third part axially between and in surface-to-surface engagement with first and second parts  46  and  48 . 
     Third or turbine part  50  is of generally ring-shaped configuration having a planar portion  64  from which upstands a plurality of annularly extending boundary ribs  66  having their adjacent free ends  66   a  and  66   b  arranged to overlap one another, so as to radially bound nozzles  38 , and a plurality of pairs of parallel guide ribs  68   a  and  68   b , which cooperate to define guideways  70  arranged to extend radially of axis  22 . Free ends  66   b  may additionally serve to define radially inwardly facing stops  72 , which partially extend across the radially outer ends of guideways  70 , as best shown in FIGS. 2 and 3. An opposed pair of boundary ribs  66 , 66  are formed with axial projections  66   c , 66   c  which are arranged for receipt within notches  58 , 58  for purposes of keying third part  50  for rotation with second part  48 . 
     In the illustrated construction, parts  46 ,  48  and  50  cooperate to define passageway  40 . More specifically, passageway  40  includes an annular inner part  40   a , which communicates with radially extending openings  30  and is axially bounded by facing surfaces of outer end parts  46  and  48 ; and an outer part or parts  40   b , which communicate one with each of nozzles  38  and inner part  40   a , and are axially bounded by facing surfaces of planar portion  64  of part  50  and part  48 . 
     Second member  42  is best shown in FIGS. 1,  2 ,  3  and  4  as including a ring-shaped mounting portion  74 , which carries a plurality of valve portions  76  arranged to extend radially of axis  22 . Each of valve portions  76  includes a radially inner part  76   a , which is arranged to be slidably received within one of guideways  70  and be connected to mounting portion  74  by a narrow connecting web  76   b , and a radially outer part  76   c  arranged to be moved towards and away from an inwardly facing surface  66   d  of an associated boundary rib  66  for purposes controlling flow through an outer passageway part  40   b  towards one of nozzles  38 . 
     It will be understood that second member  42  is formed from a resiliently deformable or elastic material biased to normally assume a first or as formed configuration shown in FIG. 2 when shaft  14  and first member  36  are subject to a some given first rotational speed, such as zero. In this first configuration, outer part  76   c  of each valve portion  76  assumes a first radial position relative to an associated outer passageway part  40   b , whereby to permit some given maximum rate of flow of fluid towards an associated nozzle  38 . As the rotational speed of shaft  14  and, thus, first member  36  increases, second member  42  due by subject to progressively increasing degrees of resilient deformation until the second member reaches some given second configuration, such as that shown in FIG. 4, wherein outer part  76   c  of each valve portion  76  assumes a second radial position relative to its associated outer passageway part  40   b , whereby to reduce flow of fluid towards nozzles  38  to some minimum valve. In operation, the high initial fluid flow rate serves to initiate rotation of the drive shaft  14  and the final reduced fluid flow rate serves to limit or define a desired maximum operational rotational speed of the drive shaft. Subsequently, during the use, an increase in load to which the tool is subjected will cause a reduction in the rotational speed of the tool. Any such reduction in speed will cause valve portions  76  to move towards their first positions, whereby permitting an increase in flow through nozzles  38 . It is to be noted that, while all portions of second member  42  become stressed dye to resilient deformation incident to change in rotational speed between conditions depicted in FIGS. 2 and 4, the maximum stress and degree of resilient deformation occurs in mounting portion  74 , as generally shown in FIG.  4 . Preferably, second member is shaped and formed from a resiliently deformable material, such as a nitrile elastomer, chosen to allow its second configuration to be determined by a balancing of the combination of elastic forces acting on the second member and dynamic forces resulting from the flow of pressure past the outer ends of valve portions  76  against the centrifugal force acting on the second member. Alternatively, the second configuration may be determined by positioning stops  72  for motion limiting abutting engagement by outer end parts  76   c  of valve portions  76 . 
     While a preferred construction employs four guideways  70  and slidably associated valve portions  76  spaced annularly of axis  22  through approximately 90° from one another, it is contemplated that these may be replaced by a pair of radially aligned guideways and valve portions spaced annularly of the axis through 180°, or by only a single guideway and associated valve portion when same is provided in combination with a suitable radially aligned weight spaced therefrom annularly through 180°. In like manner, the number of nozzles  38  may be varied, if desired, to correspond to the number of guideways and valve portions. 
     FIG. 6 depicts an alternative form of the present invention, wherein like parts are designated by like primed numbers. More specifically, this form of the invention differs from that described above primarily in that the discharge opening(s)  38 ′ need not be shaped and sized to define efficient propulsion nozzle(s) per se, but rather merely to provide for the efficient flow of pressurized fluid to drive a vane motor  80  mounted coaxially with the governor mechanism on shaft  14 ′. Motor  80  may be of the general type conventionally employed to drive hand held, pneumatically operated tools, such as rotary grinders and sanders, and thus same is only partially shown and described as including a motor end plate  82  and motor cylinder  84  carried by housing  12 ′ and a rotor  86  and vanes  88  carried for rotation with shaft  14 ′. Fluid exhausted from motor  80  may be discharged from housing  12 ′ in any suitable manner. In operation, second member  42 ′, which is resiliently deformable in response to change in the rotational speed of shaft  14 ′, serves to vary the flow of pressurized fluid through passageway  40 ′ for discharge through opening(s)  38 ′ for supply to motor  80 , and thereby permit control of the rotational speed of the motor, the shaft, and parts  42 ′,  46 ′,  48 ′ and  50 ′. 
     FIG. 7 depicts a modification of the construction shown in FIG. 6, wherein like parts are designated by like double primed numbers. More specifically, this form of the invention differs from that described in FIG. 6 primarily in that discharge opening(s)  38 ″ are shown as opening in a direction extending generally parallel to axis  22 ″, as opposed to tangentially of second member  42 ″, and passageway  40 ″ is shown as being defined solely by second part  48 ″ and arranged to also extend generally parallel to axis  22 ″. Pressurized fluid is suitably constrained for flow through passageway  40 ″, such as by providing housing  12 ″ with an internal annular sealing rim  90  sized to form a close rotational fit with the periphery of second part  48 ″. If required, rim  90  may be provided with a suitable sealing device  92 . As with the case of the previously described construction of FIG. 6, second member  42 ″, which is resiliently deformable in response to change in rotational speed of shaft  14 ″, serves to vary flow of pressurized fluid passing through passageway  40 ″ for discharge through opening(s)  38 ″ for subsequent supply to motor  80 ″, and thereby permit control of the rotational speed of the motor.