Abstract:
Mechanisms for reducing power output of a power tool by restricting airflow into the motor of the tool. The power regulator can be implemented in only one of the rotational directions, for example, the forward (or clockwise) direction, and can be independent of the forward/reverse mechanism to avoid a user becoming confused as to the source of tactile feedback. By limiting air input to the motor, rather than bleeding out motor output, the mechanisms prevent wasted power output. Also, the power regulation mechanism can be located near the motor to more effectively restrict airflow.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to controlling the amount of power output of a rotational tool, such as a pneumatic or hydraulically powered tool. More particularly, the present invention relates to controlling power output by restricting the amount of air or fluid entering a rotational motor for only one of two rotational directions of the motor. 
       BACKGROUND OF THE INVENTION 
       [0002]    Power tools commonly use pneumatic or hydraulic mechanisms for powering the tool. For example, impact wrenches use rotational motors having rotors that receive pressurized air or fluid to produce a rotational force to a work piece. The pressurized air or fluid causes rotation of the rotor of the motor. 
         [0003]    Many times, a user may desire to reverse the rotational direction of the power tool, for example, when the work piece is left-hand threaded or when the user desires to loosen the work piece instead of tighten it with the power tool. Conventional power tools include reversing mechanisms that change the rotational direction of the tool so that the user can switch between clockwise and counterclockwise rotational directions of the tool. This is typically accomplished by an internal valve assembly that switches the internal direction of the pressurized air or fluid from one side of the rotor to the other. 
         [0004]    Similarly, conventional power tools include mechanisms to control the power output of the tool by controlling the amount of pressurized air or fluid that effectively turns the rotor. However, such power tools cannot independently regulate the power output of only one of either the clockwise or counterclockwise rotational directions of the tool. Rather, such tools regulate both the clockwise and counterclockwise directions without discretion. Yet, it is often desirable to regulate rotational power output of the clockwise and counterclockwise rotational directions differently. For example, it is often desirable to require less power when tightening a work piece (such as when the tool is operated in the clockwise direction), and unrestricted or maximum power when loosening a work piece (such as when the tool is operated in the counterclockwise direction). However, since some power tools regulate power output in both rotational directions without differentiation, the conventional systems cannot control power output of only one of the rotational directions. Moreover, tools often regulate power using the same mechanism as the forward and reverse mechanism, causing the user to confuse the tactile feedback from the forward/reverse mechanism as that of the power regulator. 
         [0005]    Moreover, some power tools typically regulate power by redirecting and releasing a certain amount of pressurized air delivered to the rotor of the motor, thus decreasing the amount of pressurized air that effectively rotates the rotor of the motor. The released air pressure is typically released from the tool to the environment, commonly known as “bleed off.” Such bleed off air is thus wasted and unused, thus causing increased costs and time (e.g., an air compressor must run more often due to the released and unused air). 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is methods and systems for controlling power output of one of the clockwise and counterclockwise rotational directions of a rotational pneumatically or hydraulically powered tool by selectively controlling the amount of air or fluid delivered to the rotor of the motor. The power regulator can be independent from the forward/reverse selection mechanism, thus providing its own, separate tactile feedback. By controlling the amount of air or fluid input to the rotor, rather than allowing undesirable air delivered to the rotor output to “bleed-off,” the invention achieves greater power efficiency and less waste. Also, because the power regulation mechanism is located proximate the motor, the mechanism can be more effective at controlling air or fluid flow, and provides a compact and ergonomic configuration. 
         [0007]    In particular, the present invention is a mechanism for controlling air or fluid flow into a rotational motor having a rotor by including a plate having a tube and a passage allowing an amount of air or fluid passage into the rotor of the motor, a valve adapted to be inserted into the tube and maintained within the plate to control the direction of rotation of the motor, where the valve is selectively movable by a user to select one of either clockwise and counterclockwise rotational directions of operation of the motor, and a restrictor plunger disposed within the plate and selectively movable between a restricted position, where the plunger at least partially covers the opening and controls the amount of air or fluid entering the rotor of the motor, and an unrestricted position, where the opening is substantially unrestricted by the plunger and allows substantially unrestricted air or fluid flow into the rotor of the motor for maximum rotational power. 
         [0008]    The present invention is also a tool including a motor adapted to utilize pressurized air or fluid to power a tool, a controlling mechanism operatively coupled to the motor and including a plate having a tube and an opening allowing a passage of air or fluid into the rotor of the motor, a valve adapted to be inserted into the tube and maintained within the plate, the valve selectively movable by a user to select either of clockwise or counterclockwise directions of operation of the tool, and a plunger disposed within the plate and selectively movable between a restricted position, wherein the plunger at least partially covers the opening and restricts the amount of air or fluid entering the rotor of the motor, and an unrestricted position, wherein the opening is substantially unrestricted by the plunger and allows substantially unrestricted air or fluid into the rotor of the motor for maximum rotational power. 
         [0009]    Also disclosed is a method of directing air within a tool including causing operation of a motor that provides the air to a rotor of the tool, operating a tool in one of a clockwise or counterclockwise directions of operation, and actuating a pin to control airflow to a motor of the tool only when operating the tool in the clockwise direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    For the purpose of facilitating an understanding of the invention, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the invention, its construction and operation, and many of its advantages should be readily understood and appreciated. 
           [0011]      FIG. 1  is a front, perspective, exploded view of a tool according to embodiments of the present application. 
           [0012]      FIG. 2  is a top, perspective view of the tool as assembled, and as disposed in the high restriction position. 
           [0013]      FIG. 3  is a top, perspective view of the tool as assembled, and as disposed in the low restriction position. 
           [0014]      FIG. 4  is a top, perspective view of a tool as assembled, with a cylinder, according to embodiments of the present application. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0015]    While the present invention is susceptible of embodiments in many different forms, there is shown in the drawings, and will herein be described in detail, embodiments of the invention, including a preferred embodiment, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated. 
         [0016]    While the present invention is discussed in terms of a pneumatically powered tool, such as, for example, an impact wrench, it will be appreciated that the invention can be used with any fluid or air powered tools, such as, for example, hydraulic tools, without departing from the scope and spirit of the present invention. 
         [0017]    The present invention is methods and systems for controlling rotational power of a power tool having an output, such as a pneumatically powered tool, for only one of first and second rotational output directions, such as clockwise and counterclockwise, of the tool. The systems control power output by restrictively controlling the amount of airflow into the rotor of the motor. Moreover, the power control mechanism can be independent of the reversing mechanism to avoid user confusion. By controlling the amount of air input to the rotor of the motor, rather than bleeding off air delivered to the rotor, the invention prevents wasted power, such as in the form of pressurized air or fluid. Also, because the power control mechanism is located near the motor, the mechanism more effectively controls airflow to the rotor and allows for a compact and ergonomic design of the tool. 
         [0018]    Referring to  FIGS. 1-4 , a power control mechanism  100  is shown having a cylinder  105  for receiving pressurized air for a rotor of a motor of a rotational tool. The cylinder  105  can be coupled to a plate  110  with a gasket  115  disposed therebetween that creates a substantially air-tight or fluid-tight connection between the cylinder  105  and plate  110 . The gasket  115  can include a first gasket portion  115   a  aligned with a first plate portion  110   a,  and a second gasket portion  115   b  aligned with second  110   b  and third  110   c  plate portions. In particular, the gasket  115  can include a gasket perimeter  120  and a gasket divider  125  dividing the gasket into first gasket portion  115   a  and the second gasket portion  115   b.  Similarly, the plate  110  can include a plate perimeter  130  extending around a periphery of the plate  110 , a plate divider  135  dividing the plate  110  axially, and a wall  140  separating the second plate portion  110   b  from the third plate portion  110   c.  Fasteners  200 , such as screws or rivets, can also be used to couple the plate  110  to the cylinder  105 , or any other component. The fasteners  200  can be any object capable of fastening two or more components together. For example, the fasteners  200  can be any type of screw, bolt, rivet, nail, adhesive, welding, or any other mechanism capable of coupling two objects together. 
         [0019]    The cylinder  105  houses a rotor of the motor that rotates to provide power to the output of the power tool. Conventional tools commonly include a valve or other device in the cylinder to “bleed off” excess air entering the cylinder to control the power output, wasting the air but reducing the power output of the motor. The present invention, however, restricts or controls the amount of air entering the cylinder  105  that houses the rotor to provide the desired output of power, rather than bleeding off the excess air from the cylinder. 
         [0020]    The plate  110  can include a tube  145  adapted to receive a valve  150  having a barrier  155  that selectively directs pressurized air to the cylinder  105 , and thus rotor, to facilitate either the clockwise or counterclockwise rotational directions of the rotor of the motor, which translates to respective clockwise and counterclockwise rotational directions of output of the tool. For example, the valve  150  can be aligned in a first position such that the barrier  155  directs pressurized air in a first direction (e.g., toward the first plate portion  110   a ), causing the power tool to operate in the clockwise direction, or the valve  150  can be aligned in a second position such that the barrier  155  directs pressurized air in a second direction (e.g., toward the second plate portion  110   b ), causing the power tool to operate in the counterclockwise direction. In an embodiment, the counterclockwise direction is unrestricted to allow maximum, unrestricted air pressure to be delivered to the rotor, thus allowing maximum rotational power in the counterclockwise direction. In an embodiment, a user can selectively rotate the valve  150  between the first and second positions to select either of the clockwise or counterclockwise rotational directions of the tool. 
         [0021]    Referring to  FIGS. 2 and 3 , the mechanism  100  is shown as selected for operating in the forward (or clockwise) direction because the barrier  155  is aligned to allow the passage of air from the third plate portion  110   c.  For example, if the mechanism  100  and power tool were operating in the reverse direction, the barrier  155  would align toward the first plate portion  110   a . As a result, when operating in the reverse direction, the mechanism  100  operates the motor at substantially full power output capacity with substantially unrestricted air flowing into the cylinder  105 . The user can select the forward or reverse mechanism in any manner (e.g., rotation of the valve  150 ), and in doing so, can shift the barrier  155  toward the first plate portion  110   a  or the third plate portion  110   c,  to choose the forward or reverse direction of operation. 
         [0022]    The plate  110  can further include a cylinder  160  adapted to receive a biasing member  165 , control plunger  170 , and pin  175 . An O-ring  180  can be circumferentially disposed around the pin  175  at a first ledge, thereby providing a substantially air-tight or fluid-tight seal between the inner wall of the cylinder and the pin  175 , when the pin  175  is disposed in the cylinder  160 , and the bias member  165  can be circumferentially disposed around an extension  190  of the pin  175  and abut against a second ledge  195  so as to form an elastically-biased member that can be movably actuated by the user to control the amount of air flow into the motor of the mechanism  100 . 
         [0023]    The plunger  170  can couple to the pin  175  in any known manner. For example, the plunger  170  can be coupled to the pin  175  with adhesive or a fastener, or can be coupled to the pin  175  based on an interference or snap fit between the plunger  170  and the pin  175 . In some embodiments, the plunger  170  can be made of rubber or other flexible material and the pin  175  can insert into the flexible material through an opening of the plunger  170 . Any other coupling mechanism between the plunger  170  and the pin  175  can be implemented without departing from the spirit and scope of the present invention. 
         [0024]    The mechanism  100  can include a first opening  205  connecting the first plate portion  115   a  with a first portion of the cylinder  105 , and a second opening  207  connecting the second  110   b  and third plate portion  110   c  with a second portion of the cylinder  105 . For example, the first opening  205  can direct the airflow from the plate  110  to the cylinder  105  when operating in the reverse or counterclockwise direction, and the second opening  207  can direct the airflow from the plate  110  to the cylinder  105  when operating in the forward or clockwise direction. The openings  205 ,  207  can be inlets to the cylinder  105  and outlets from the plate  110  so as to selectively provide air to the cylinder  105  based on the positioning of the valve  150 . For example, when the barrier  155  of the valve  150  directs air towards the first plate portion  110   a , the first opening  205  can provide the necessary air to the cylinder  105 , and when the barrier  155  directs air towards the second  110   b  and third  110   c  plate portion, the second opening can provide the necessary air to the cylinder  105 . 
         [0025]    The mechanism  100  controls the amount of pressurized air entering the cylinder  105  by axially moving the plunger  170  to change the size or surface area of the second opening  207  to the cylinder  105 . For example, as shown in  FIG. 2 , the plunger  170  can partially cover the second opening  207 , thus reducing the size of second opening  207 . Accordingly, to limit power output, the plunger  170  reduces the amount of air flowing into the cylinder  105 , rather than allowing an unrestricted amount of air to flow into the motor and bleeding off excess air to reduce power output. The mechanism  100  therefore achieves an efficient distribution of power by controlling power output in, for example, only the clockwise direction, while allowing maximum power in the opposite direction, for example counterclockwise direction. 
         [0026]    The pin  175  can be actuated inwardly to operate the mechanism  100  in the restricted air position using any method. For example, a button can actuate the pin  175  inwardly, or a knob that rotates and imparts axial displacement of the pin  175  based on the rotation of the knob (for example, a cam mechanism). The axial actuation of the pin  175  causes selective movement of the plunger  170  to control the second opening  207  size, thus controlling the amount of pressurized air delivered to the cylinder  105 . For example, if the pin  175  is only slightly actuated inwardly, the plunger  170  only partially restricts the second opening  207 , thus only slightly reducing the size of the second opening  207  to slightly reduce the amount of air delivered to cylinder  105 . It will thus be appreciated that the more that the user causes the pin  175  to be moved axially inwardly, the more that plunger  170  will restrict the second opening  207 , thus reducing the second opening  207  size, which reduces the amount of pressurized air delivered to cylinder  105 . It will further be appreciated that since the plunger  170  only affects the size of the second opening  207 , it only affects the amount of air delivered for one rotational direction of the motor, and not the other. Thus, movement of the pin  175  controls power output in only the clockwise direction, and not the counterclockwise direction, for example. In such a configuration, when counterclockwise rotational direction is selected, such as when removing or loosening a work piece, maximum rotational output can be utilized, which is desirable, without modifying the power restriction of the clockwise rotational direction. On the other hand, when selecting the clockwise rotational direction of the tool, such as when tightening a work piece, controlled rotational output can be utilized. 
         [0027]    The mechanism  100  can also include a brace  210  for maintaining a position of the valve  150  during operation of the mechanism  100 . The brace  210  can be an arcuate or cylindrical body coupled to the plate  110  and substantially retaining the valve  150  and preventing it from being dislodged during operation of the power tool. The brace  210  can therefore allow the valve  150  to be rotatable about the longitudinal axis of the valve  150  and rotate based on user control to select either the clockwise or counterclockwise rotational directions of operation. That is, when a user causes the valve  150  to be rotated in a first rotational direction, the barrier  155  rotates with the valve  150  and aligns itself in a direction substantially tangential to the desired rotational direction of the rotor of the power tool. By maintaining the positioning of the valve  150  with the brace  210 , the valve  150  can rotate within the tube  145  and be coupled at the axial ends of the valve  150  to other components of the power tool to avoid axial displacement of the valve  150 . 
         [0028]    The bias member  165  can extend around the pin  175  at the extension  190 , abut against the second ledge  195  on one end of the elastic member  165 , and abut against the wall  140  at the other end of the bias member  165 . As a result, the mechanism  100  is elastically biased toward the open position where substantially no air restriction occurs, as shown in  FIG. 3 , and thus maximum power output is obtained. However, if the user chooses to actuate the pin  175  and push it axially inward, the mechanism  100  can operate in a variably restricted position where the amount of air entering the cylinder  105  can be controlled by restriction based on the amount the pin  175  is axially actuated inwardly, as shown in  FIG. 2 . 
         [0029]    As shown, the bias member  165  is a coil spring, but the bias member  165  can be a leaf spring, torsion or double torsion spring, tension spring, compression spring, tapered spring, or simply an object elastically biased against the wall  140  and second ledge  195 . Further, the bias member  165  need not be a spring at all, or even an elastically biased object, and can be any object that applies an electrical, magnetic, mechanical, or any other type of force to the wall  140  and second ledge  195  to better bias the mechanism  100  in the unrestricted position. Any other implementation of the elastic member  165  can be carried out without departing from the spirit and scope of the present invention. 
         [0030]    As used herein, the term “coupled” and its functional equivalents are not intended to necessarily be limited to a direct, mechanical coupling of two or more components. Instead, the term “coupled” and its functional equivalents are intended to mean any direct or indirect mechanical, electrical, or chemical connection between two or more objects, features, work pieces, and/or environmental matter. “Coupled” is also intended to mean, in some examples, one object being integral with another object. 
         [0031]    The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and/or described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of the inventors&#39; contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.