Abstract:
An adjustable handle assembly is provided for use with a hand-held power tool, such as a polisher, to enhance control while operating on delicate surfaces of varying contours. The handle assembly includes a handle mounted to the housing of the tool in a manner that facilitates quick adjustment of the handle between various predetermined positions relative to the housing without the use of tools, turning of nuts and bolts and prolonged work stoppage. The handle assembly also includes lock members on one of the handle and the housing and lock receiving grooves on the other of the handle and housing which can cooperate with the lock members to fix the handle in one of the predetermined positions relative to the housing. For quick adjustment, the handle assembly includes a lock manually movable by a user between a locking position in which the lock members are urged into the grooves to lock the handle relative to the housing and a release position in which the lock members are free to move from the grooves, thereby allowing the handle to be adjusted relative to the housing between the predetermined positions. The handle assembly also includes a cam means located between the lock and the handle to urge the lock members into the locking position with the grooves. The cam means may include cooperating cam surfaces on the lock and the handle.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a hand-held power tool and, more particularly, to a hand-held power tool capable of polishing operations with a readily adjustable handle assembly that permits an operator to ergonomically adjust handle positions to enhance control and coverage of the tool during operation. 
     BACKGROUND OF THE INVENTION 
     Typically, power tools, such as polishers or waxers, for use on delicate work surfaces of varying conto tours, including exterior car finishes, tend to lack a structure for effective and precise operator control and maneuverability during operation on the surface. Such power tools commonly include a motor that drives a working element, such as a polishing or waxing pad, in an orbital path for engagement with the work surface. To prevent damage to the work surface, it is important that an operator be able to precisely guide the working element over the work surface and to simultaneously control the pressure with which the working element is applied to the work surface. For instance, if the tool is used with too much pressure, such as by not being able to control and prevent the entire weight of the tool from being applied to the working element and, consequently, the work surface, the finish on the work surface can be easily damaged or even ruined. On the other hand, too little application pressure will tend to result in the surface finish not being polished properly or in an increase in operation time to accomplish the desired finish. 
     The vibratory response associated with polishing with the working element under orbital motion further complicates the polishing operations. It has been found that such response felt by operators using orbital motion is significantly greater than that associated with other non-orbital type tools. Thus, the structure of the power tool must take into consideration this response. 
     To increase efficiency, it is also desirable that an operator be able cover a relatively large area on the work surface, while at the same time maintaining control over the application pressure and path of the tool during operation. This is usually accomplished by either relocating to a different location relative to the work surface or by extending one&#39;s arms over and about the work surface. The latter technique is used most often when polishing remote areas that cannot be accessed by simply relocating, such as when polishing central areas of an automobile, e.g., central areas of the hood, roof and trunk. As mentioned above, experience, however, has taught that accuracy and precision is sacrificed when operating the tool with one&#39;s arms extended because of the increased vibrational response from orbital motion. 
     To enhance control and expand the reach of these tools from a single location and otherwise, it is known to provide a right angle tool with a barrel type handle that extends from the rear of the tool perpendicular to the orbital path of the working element. While the tool can be operated by gripping the barrel handle only, experience has revealed that another handle forward of the barrel handle is preferred so that the operator is able to grip the barrel handle with one hand and the other handle with the other hand. The barrel handle provides increased control over the tool&#39;s path of operation, and the forward handle aids in controlling the application pressure to the work surface. Without the forward handle, there tends to be, in many instances, an uncomfortable amount of force applied to the hand, wrist and arm gripping the barrel handle. Thus, the combination of handles provides for maximum precision control of the application pressure while allowing the barrel handle to be used to steer the tool. 
     One known shortcoming associated with these multiple handle arrangements, however, is the inability to maximize the utility of the barrel grip handle. While the barrel handle provides increased control and reach, operators, as mentioned above, find that it is still necessary to grip the forward handle during operations, especially on delicate work surfaces, for complete control to avoid damage. This, however, effectively limits the range of area operators can reach with the tool from a single location because they must also extend their arms to reach the forward handle. 
     Moreover, it is desirable that the forward handle be adjustable to maximize reach and ergonomical control on varying surface contours and orientations. Many of these forward handle however, are fixed and, therefore, cannot be adjusted to provide this reach and control. As a result, operators contort their body into uncomfortable and compromising positions to compensate for the limitation of fixed forward handles during operation and are open to an increased potential for injury. Furthermore, the work surface also is exposed to a higher potential for damage. 
     Some power tools include adjustable forward handles which are released for movement and tightened down for operation by way of a bolt and nut combination. The nut is loosened to free the handle for adjustment and then is tightened to lock the position. This type of adjustment system is not easily controlled by the operator and results in undue work stoppage. It is desired to have a system that can be quickly adjusted and done so without tools and/or having to manually loosen and tighten nuts and bolts. 
     Thus, the present invention is directed to providing an adjustable handle assembly for use with hand-held power tools that can be easily adjusted without prolonged work stoppage to allow an operator to effectively and accurately control the working element over relatively large working areas and varying surface contours in an efficient, comfortable and safe manner. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an adjustable handle assembly for use with a hand-held power tool, such as a polisher, to enhance control and coverage while operating on delicate surfaces of varying contours and orientations. The handle assembly includes a handle mounted to a housing of the tool in a manner that facilitates easy and quick adjustment of the handle between various predetermined positions relative to the housing. As a result, the operator is able to adjust the handle depending on the contour and orientation of the surface without tools or prolonged work stoppage. 
     The handle assembly includes lock members on one of the handle and the housing and lock receiving grooves on the other of the handle and housing which can cooperate with the lock members to fix the handle in one of the predetermined positions relative to the housing. For quick adjustment, the handle assembly includes a lock manually movable by an operator between a locking position in which the lock members are urged into the grooves to lock the handle relative to the housing and a release position in which the lock members are free to move from the grooves, thereby allowing the handle to be adjusted relative to the housing between the predetermined positions. The predetermined positions to which the handle is adjustable include at least a flat position where the handle extends substantially perpendicular to a first direction extending along a longitudinal axis through the housing and aligned with the orbital path axis and an upright position where the handle extends substantially in the first direction. 
     The handle assembly also includes a cam means located between the lock and the handle to urge the lock members into the locking position with the grooves. The cam means may include cooperating cam surfaces on the lock and the handle. In manually moving the lock to the locking position, the lock cam surface cams against the handle cam surface to urge the lock members into the grooves with a biasing force sufficient to lock the handle. On the other hand, in manually moving the lock to the released position, the lock cam surfaces cam against the handle cam surface in the opposite direction to remove the biasing force from the lock members to allow adjustment of the handle. The use of the cam means to lock and release the handle allows the lock members to be controlled without turning screws or bolts to hold the locked position secure. Advantageously, the lock on the handle assembly is easily controlled by the operator without tools or prolonged work stoppage. 
     The lock members may be urged into the grooves in a first direction with the lock in the locking position and the lock members may cam out from the grooves and move in a second direction transverse to the first direction as the handle is adjusted with the lock in the release position. The first direction may be linear and the second direction may be angular. The lock members and lock receiving grooves may also include cam surfaces which cooperate to allow the lock members to cam out of the grooves as the handle is adjusted with the lock in the release position. 
     The adjustable handle assembly may include a guide between the handle and the housing for defining movement of the handle relative to the housing as the handle is being adjusted between the predetermined positions. The guide may include a stop for limiting movement of the handle relative to the housing. 
     The handle assembly also may include an elongated retention member to attach the handle to the housing. The lock is moved along the member by the cam means when shifting between the locking and release positions. 
     In another form of the present invention, an orbital polisher has a housing and a motor therein for driving a polishing pad in an orbital path below the housing. The polisher further includes a rear handle extending rearwardly from the housing and a front adjustable bail handle extending from and around the housing forwardly of the rear handle to assists a user in controlling the tool with the pad in rubbing engagement with a surface to be polished. 
     A locking mechanism cooperates between the front bail handle and the housing for selectively locking the bail handle in one of a plurality of predetermined positions about the housing. A lock operator movable along the bail handle by a user actuates the locking mechanism to either selectively lock the bail handle in one of the plurality of predetermined positions about the housing or release the bail handle for adjustment about the housing. The bail handle attaches to two surfaces of the housing, and the control of the locking mechanism through the lock operator locks the bail handle at each surface. The lock operator enables the user to quickly adjust one handle without turning of any nuts and bolts and by prolonged work stoppage. The bail handle, however, may be adapted to lock the handle at only one of the surfaces. 
     The polisher also may include an arcuate guide on one of the housing and bail handle and an arcuate recess on the other of the housing and bail handle. The guide and recess cooperate to guide the bail handle through at least about 90° of movement for adjustment about the housing. The arcuate guide may extend less than about 180° and the arcuate recess may extend more than about 180° to allow the guide to move in the recess as the handle is adjusted. 
     The bail handle also may include an actuator receiving portion and the lock operator may include an operator lever and an actuator knob connected to the lever. The actuator knob is located in the actuator receiving portion of the bail handle and the lever projects there-from. Pivoting of the lever to rotate the actuator knob causes the knob to move along the bail handle in the actuator receiving portion to actuate the locking mechanism. 
     The knob and the actuator receiving portion of the bail handle also may include cooperating cam surfaces. Pivoting of the lever by the user to a lock position causes the cam surface on the knob to cam against the cam surface on the bail handle to move the knob along the bail handle in the actuator receiving portion away from the locking mechanism to urge the bail handle towards the housing for selectively locking the bail handle in one of the plurality of predetermined positions about the housing. 
     The locking mechanism of the polisher also may be provided with locking teeth on one of the bail handle and the housing and grooves in the other of the bail handle and the housing. The lock operator is capable of actuating the teeth to seat tightly in corresponding grooves for locking the bail handle about the housing. The locking mechanism also may include locking teeth and grooves that have cooperating cam surfaces wherein, when the lock operator actuates the locking mechanism to release the bail handle, adjustment of the bail handle causes the teeth cam surfaces to cam against the groove cam surfaces with the teeth moving out of the grooves and over adjacent grooves to another of the plurality of predetermined positions about the housing. 
     In an even further form of the present invention, a power tool includes a housing having a top, bottom, front and back and a longitudinal tool axis in the housing extending in a first direction through the housing top and bottom intermediate the front and back thereof. A rear handle extends out rearwardly from the back of the housing substantially perpendicularly to the first direction. A bail handle having an interior chamber extends around the front of the housing and is adjustable to at least a flat position extending substantially perpendicular to the first direction and an upright position extending substantially in the first direction. The tool further includes a bail handle lock which is at least partially located in the interior chamber and is manually operable by a user to lock the bail handle in at least the flat and upright positions about the housing. 
     The bail handle of the power tool may also include rear portions rotatably connected adjacent the back of the housing, side portions extending from the rear portions and a front lateral portion extending between the side portions and spaced from the rear portions. The bail handle front portion is adjustable from in front of the housing with the bail handle in the flat position to over the top of the housing with the bail handle in the upright position by rotating the handle rear portions relative to the housing. 
     The bail handle also may include rear portions of the bail handle having one of a plurality of teeth and grooves and the housing adjacent the back thereof having the other of the plurality of teeth and grooves. The bail handle lock causes the teeth to seat tightly in the grooves for locking of the bail handle or to release the teeth from in the grooves to allow movement of the teeth out of and over the grooves for rotating of the bail handle rear portions and adjustment of the bail handle about the housing. 
     The bail handle lock also may be located at one of the bail handle rear portions. When the lock is moved to a lock position, it pushes the rear portions towards the housing causing the teeth to seat tightly in the corresponding grooves, and when the lock is moved to an unlocked position, it allows movement of the teeth out of and over the grooves for adjusting the handle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be described in connection with the accompanying drawings wherein: 
     FIG. 1 is a top plan view of a hand-held power tool with an adjustable handle assembly embodying features of the present invention; 
     FIG. 2 is a left side elevational view of the hand-held power tool of FIG. 1 illustrating different positions of a handle of the adjustable handle assembly; 
     FIG. 3 is a partial, exploded perspective view of the adjustable handle assembly of FIG. 1 to illustrate features of the locking mechanism at the left side of the assembly; 
     FIG. 4 is a perspective view of the locking knob of the locking mechanism at the left side of the handle assembly of FIG. 1 to illustrate the sam surfaces on the locking knob; 
     FIG. 5 is a partial, exploded perspective view of the adjustable handle assembly of FIG. 1 to illustrate features of the locking mechanism at the right side of the assembly; 
     FIG. 6 is a cross-sectional view of the locking mechanism of the adjustable handle assembly taken along the line  6 — 6  of FIG. 1 to illustrate the locked state; 
     FIG. 7 is a cross-sectional view of the locking mechanism of the adjustable handle assembly taken along the line  6 — 6  of FIG. 1 to illustrate the released state; 
     FIG. 8 is an enlarged perspective view of the locking grooves and rotational limiting lug of the locking mechanism of the adjustable handle assembly of FIG. 1; and 
     FIG. 9 is an enlarged perspective view of the locking teeth and rotation limiting lug pocket of the locking mechanism of the adjustable handle assembly of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2 of the drawings, there is illustrated a right angled, hand-held power tool  12  capable of being used in polishing operations. The tool  12  includes an adjustable handle assembly  10  embodying features of the present invention. In general, the tool  12  has a central housing  14  in which operates an electric motor capable of rotating a polishing pad  16  in an orbital path below the housing  14 . A rear barrel handle  18  extends from the housing  14  perpendicularly to the orbital rotation and includes a trigger  20  to activate the motor and a trigger lock  22  to maintain the trigger  20  in the active position for extended use segments. A power cord (not shown) attaches to the rear end  19  of the barrel handle  18  to supply power to the motor in the housing  14 . 
     During operation, the tool  12  is gripped at its rear barrel handle  18  with one hand and at a forward handle  30  of the handle assembly  10  with the other hand. To provide maximum control and an ergonomical reach over a wide range of surface contours and orientations, the handle  30  is adjustable to various orientations relative to the rear handle  18 , including a level state and, as illustrated in phantom, a 45° and 90° state. The handle assembly  30  allows for this adjustment to be made quickly without tools or prolonged work stoppage. 
     The housing  14  includes a left side  24 , right side  26  and front end  28 . The handle  30  is a bail type handle with an arcuate shape extending around the housing  14  between the left housing side  24  and the right housing side  26 . For instance, the handle  30  is capable of extending around the front end  28  when pivoted to the level state with the barrel handle  18 . The bail handle  30  includes turned in left and right ends  32  and  34 , respectively, which are pivotally connected to the housing  14  at the juncture between the barrel handle  18  and the housing  14 . The handle may be of sturdy plastic material and injection molded in two pieces that are ultrasonically welded together. 
     The adjustable handle assembly  10  has each end  32  and  34  of the handle  30  adapted to cooperate with corresponding housing sides  24  and  26  to lock the handle  30  at both sides in the desired orientation. The assembly  10  also includes a shiftable cam activated locking mechanism  36  at the left turned in end  32  that operates to shift the handle  30  between a released state for setting the handle  30  to its desired orientation and a locked state for shifting the cooperating arrangement between the ends  32  and  34  of the handle  30  and the sides  24  and  26  of the housing  14  to lock the desired handle orientation. The adjustable handle assembly, however, may be adapted to lock the handle at one side of the housing. 
     Referring to FIGS. 3,  4 ,  6  and  7 , the handle assembly  10  is mounted generally to the housing  14  with an elongated retention means in the form of a screw  38  that allows for pivotal rotation of the handle  30  in the released state. The screw  38  extends through the housing  14  to interconnect the left and right turned in ends  32  and  34  of the handle  30 . The screw  38  includes an enlarged head  40  at one end that resides in an internal bore  42  formed in the left end  32  of the handle  30  adjacent the locking mechanism  36 . A fastener in the form of a nut  44 , preferably self-locking, is turned on threads  38   a  at the end opposite the head  40  and resides in an internal nut pocket  46  formed in the right end  34  of the handle  30 . The purpose of the nut  44  is to fix the distance along the screw  38  between the head  40  and the nut  44  so that it always remains the same when shifting between the locked and released states. The cam activated locking mechanism  36  shifts the handle ends  32  and  34  between the locked and released states along the screw  38  without rotation of bolts and/or nuts. Thus, any type of shaft and end fasteners may be used as long as this distance is fixed. 
     Referring to FIGS. 3,  5 ,  8  and  9 , both the left and right ends  32  and  34  of the handle  30  have four pairs of radial locking teeth  48  (FIG. 9) projecting toward the sides  24  and  26  of the housing  14 . The adjacent pairs of locking teeth  48  are situated at intervals that are approximately 90° apart. The locking teeth  48  are designed to sit in radial locking grooves  50  (FIG. 8) formed in the left and right housing sides  24  and  26 . The handle  30  is made such that it biases against the housing  14  with a small amount of pressure to keep the locking teeth  48  seated in the locking grooves  50  generally, but also allowing the locking teeth  48  to ratchet over the locking grooves  50  for pivoting the handle  30  to different positions in the released state. In the locked state, the teeth  48 , however, are lodged into engagement with the locking grooves  50  under increased pressure from the locking mechanism  36 , which keeps the locking teeth  48  from being ratcheted over the locking grooves  50 , thereby securing the handle  30 . The grooves  50  are spaced one after another at generally equal intervals for about 360° at the juncture between the housing  14  and the handle  30  and are complementary in shape to the teeth  48 . As illustrated, there are sixteen grooves  50 . 
     The teeth  48  are wedge shaped with a flat top  52  and ramped sides  54  and oriented to increase in width radially outward. The teeth  48  project axially toward the housing  14  with length sufficient to establish a secure bite with the grooves  50  to prevent the handle  30  from turning while in the locked state. Accordingly, the depth of each groove  50  is coordinated to match the teeth  48  length so that the top  52  and ramped sides  54  engage a flat bottom surface  56  and ramped side surfaces  58  defining each groove  50  when in the locked state. 
     In the released state, the locking mechanism  36  releases the pressure to allow the teeth to be able to pass by the grooves  50  to allow the handle  30  to be pivoted to another desired orientation. The ramped sides  54  and surfaces  58  of the teeth  48  and grooves  50 , respectively, are designed to cam over one another to aid in spacing the teeth  48  from the grooves  50  and to otherwise free the handle ends  32  and  34  from a locked engagement with the housing  14  for pivoting. During pivoting, the teeth  48  then can ratchet over the grooves  50  under the small amount of biasing pressure provided by the handle  30 . 
     Referring to FIGS. 6-9, the pivoting action of the handle  30  is guided at the junctures between both the left and right ends  32  and  34  and the housing  14 . Through this guided action, the range for the handle  30  is limited to a preferred range of approximately 90°. More particularly, at each side  24  and  26  of the housing  14 , there is a bore  60  for the screw  38  centrally located in the area defined by the radial grooves  50 . The screw  38  extends through these bores  60  to extend through the housing  14 . An arcuate lug  62  projects from the housing  14  about the bore  60  at each side  24  and  26  of the housing  14 . Each lug  62  sits in an arcuate lug pocket  64  formed in the ends  32  and  34  of the handle  30 , and extends about a handle attachment bore  66  located in the center area defined by the radial locking teeth  48 . The screw  38  extends into the handle  30  at the internal bore  42  in the left end  32  and through the bore  66  and into the left side  24  of the housing  14  through bore  60 . At the other side, the screw  38  extends from the right side  26  of the housing  14  through the bore  60  and into the handle  30  through the bore  66  in the right end  34  and terminates in the internal nut pocket  46 . 
     Both the lug  62  and pocket  64  have an outer arcuate surface  68  and  70 , respectively, that slide against one another during pivoting of the handle  14  and provide support at the juncture between the handle ends  32  and  34  and the left and right sides  24  and  26  of the housing  14  when the tool  12  is in use. The arcuate lengths of the lug  62  and pocket  64  are coordinated to provide the desired range of pivoting. For instance, the arcuate length of the lug  62  should extend a sufficient arcuate length to provide the desired support at the juncture, and the pocket  64  should be sufficiently longer to allow the lug  62  to move in the pocket  64  to permit the desired pivoting range for the handle  30 , i.e., preferably, approximately 90°. To limit pivoting, each lug  62  includes a pair of end surfaces  72  capable of engaging corresponding end surfaces  74  in the pocket  64  to limit the rotational movement of the handle  30 . 
     Referring to FIGS. 6 and 7, the projection length of each lug  62  and the depth of each lug pocket  64  are greater than that of the radial locking teeth  48  and the locking grooves  50 , respectively. A portion of the lug  62  remains in the lug pocket  64  to guide pivoting of the handle  30  when the locking mechanism  36  is in the released state. More particularly, the lug  62  includes a top surface  78  which is engaged with a bottom surface  80  of the pocket  64  when in the locked state (FIG.  6 ). In the released state, the locking teeth  48  are able to move from their locking engagement with the locking grooves  50 , while the lug  62  remains in the lug pocket  64  with the top surface  78  releasing only from the bottom surface  80  and not entirely from the lug pocket  64  (FIG.  7 ). In this released state arrangement, the arcuate surfaces  68  and  70  of the lug  62  and lug pocket  64 , respectively, guide rotation and the end surfaces  72  and  74  of the same limit rotation to the maximum range. This operation is similar at both junctures between the left and right handle ends  32  and  34  and the left and right sides  24  and  26  of the housing  14 , respectively. 
     Referring to FIGS.  3  and  5 - 7 , the shiftable cam activated locking mechanism  36  is located in the left end  32  of the handle  30  and shifts the handle  30  between its locked state (FIG. 6) and released state (FIG.  7 ). The locking mechanism  36  includes a locking knob  82  having a cylindrical shaped body  84  located in a hollow chamber  86  formed in the left end  32  of the handle  30  with a complementary shape. A lever  88  projects perpendicularly from the body  84 , which is manually moved to rotate the body  84  to operate the locking mechanism  36 . The lever  88  projects from the handle  30  through an arcuate slot  90  that is formed through half of the left end  32  and that extends approximately 180°. The slot  90  allows the lever  88  to be manually moved to rotate the body  84  approximately 180° in the chamber  86 . 
     The body  84  includes a central attachment bore  92  through which passes the screw  38  and an outer arcuate surface  94  that slides over an arcuate inner surface  96  defining a portion of the chamber  86 . The body  84  has a flat surface  98  at one end and a pair of arcuate ramped cam surfaces  100  at the opposite end. The cam surfaces  100  extend contiguously for approximately 180° each and are separated by a pair of radially extending steps  102 . 
     The screw  38  extends through the internal bore  42  in the left end  32  of the handle  30  so that the head  40  is in position to engage the flat surface  98  of the body  84 . A washer  104  is situated on the screw  38  between the head  40  and the flat surface  98  of the body  84 . With the screw  38  having a fixed length between the head  40  and washer  104  on one end and the nut  44  on the other, the body  84  is designed to shift axially in the chamber  86  to either take up play along the screw  38  to draw the left and right ends  32  and  34  into locking engagement with the left and right sides  24  and  26  of the housing  14  to set the locked state (FIG. 6) or to provide sufficient play along the screw  38  for setting the release state in which the handle  30  is free to pivot under the slight biasing pressure of the handle  30  itself with the locking teeth  48  ratcheting over the locking grooves  50  (FIG.  9 ). 
     More particularly, to shift the body  84  axially in the chamber  86 , the ramped cam surfaces  100  of the body  84  cooperate with another pair of similar arcuate ramped cam surfaces  106  on the ends of the handle  30  that face toward the body  84 . The cam surfaces  106  on the handle are similar to those on the body  84  and extend contiguously for approximately 180° and are separated by a pair of radially extending steps  108 . The cam surfaces  100  and  106  slide against one another to shift the body  84  in the chamber  86  along the handle  30  axially away from the housing  14  when the locking knob  82  is rotated clockwise for setting the locked state (FIG. 6) and toward the housing  14  when the knob  82  is rotated counter-clockwise for setting the released state (FIG.  7 ). 
     When the knob  82  has been turned all the way clockwise, until the lever  88  abuts the slot  90 , the cam surfaces  100  and  106  have slid over one another until the highest portions  100   a  and  106   a  of each are in engagement and the lower portions  100   b  and  106   b  are spaced from one another. In this position, the steps  102  and  108  also are in alignment axially. This causes the body  84  to apply outward pressure to the head  40  and washer  104  at its flat surface  98  and, at the other side, the nut  44  to tighten against the bottom of the nut pocket  46  adjacent the bore  60  for the screw  38 . As a result, all of the play in the predetermined distance along the screw  38  between the head  40  and washer  104  on the one end and the nut  44  on the other has been removed and the right and left ends  32  and  34  of the handle  30  have been drawn toward the housing  14  to seat the locking teeth  48  in the locking grooves  50  under sufficient pressure lock the handle  30  for use (FIG.  6 ). 
     On the other hand, when the locking knob  82  has been turned all the way counter-clockwise, until the lever  88  abuts the opposite side of the slot  90 , the cam surfaces  100  and  106  have been moved to their lowest position, in which the lower portions  100   b  and  106   b  of each surface  100  and  106 , respectively, are engaged with one of the higher portion  106   a  and  100   a , respectively, of the opposing cam surfaces. In this arrangement, the steps  102  and  108  are in engagement with one another, and the body  84  has been moved along the handle  30  toward the housing  14 . This causes play to be provided along the screw  38  between its fixed ends (FIG.  7 ). That is, the head  40  and washer  104  are not tight against one flat surface  98  of the knob  84  and the nut  44  is not tight against the bottom of the internal nut pocket  46 . This results in sufficient freedom at the left and right ends  32  and  34  of the handle  30  so that the locking teeth  48  are able to cam out of and ratchet over the locking grooves  50  for pivoting the handle  30  to a different position when in the released state. 
     In operation, to set the handle  30  to a different orientation, the lever  88  of the shiftable cam locking mechanism  36  is first rotated all the way counter-clockwise to set the released state, in which the body  84  has been moved along the handle  30  toward the housing  14  to provide play in the handle assembly  10  along the screw  38 . This play allows the locking teeth  48  to move between the locking grooves  50  so that the handle  30  can be easily pivoted to a different desired orientation. In effect, the locking teeth  48  ratchet over the locking grooves  50  as the handle  30  is pivoted to a different position. The slight biasing force of the handle  30  causes the handle  30  to remain in the desired position until the locking mechanism  36  is shifted to the locked state. 
     Once in the desired position, the lever  88  is rotated all the way clockwise to set the locked state, in which the body  84  has been moved along the handle  30  away from the housing  14  to take up any play in the handle assembly  10  along the screw  38 . In the locked state, the locking teeth  48  are securely lodged in the locking grooves  50 , thereby preventing the handle  30  from pivoting. Thus, the whole operation of shifting the handle  30  is done without the time consuming use of tools and turning of nuts and bolts. 
     Each of the foregoing component parts of the present invention may be of sturdy plastic material and may be injection molded. 
     It will be understood that various changes in the detail, materials and arrangement of parts and assemblies which have been herein described and illustrated in order to explain the nature of the present invention may be made by those skilled in the art within the principle and scope of the present invention as expressed in the appended claims.