The invention relates to dual pawl ratchet mechanisms and, in particular, to an improved reversible dual pawl device and method.
Currently, many dual pawl ratchet mechanisms are known and used. Typically, these mechanisms are incorporated into handtools, such as wrenches and/or screwdrivers, or the like, so that there is a drive portion engageable with, for example, a bolt head. A first drive direction may be selected for the dual pawl ratchet mechanism so that use of the handtool provides torque when engaged with the bolt head and rotated in a first direction while slipping or ratcheting when rotated in a second direction. A second drive direction may be selected for the dual pawl ratchet mechanism that is opposite the first drive direction, and that provides torque and slip in the opposite directions.
In operating the reversible dual pawl mechanism, there is typically a manually actuable portion, commonly referred to as a reversing lever, that effects the engagement of one pawl and the dis-engagement of a second pawl, the actuable portion being commonly referred to as a reversing lever. The drive direction for the drive portion is dependent on which of the two pawls is engaged.
The reversing lever is typically rotated about an axis that is generally perpendicular to a face or side of the ratchet head to engage and dis-engage the pawls and, thus, to select the drive direction. The axis of rotation for the reversing lever is generally parallel to the axis of rotation of drive portion that provides the torque.
One of the problems with these handtools is the amount of rotation of the reversing lever. It is not uncommon to provide a spring and ball assembly, the spring biasing the ball into a detent, for defining the positions for the reversing lever. If the ball and detent cooperation is significant (such as due to a deep detent and spring with a high spring constant), the detent and ball can become worn or damaged. On the other hand, if the cooperation is slight, the mechanism may not provide a clear tactile indication of reaching a selected position and/or may permit accidental shifting from the selected position, again leading to damage.
When the ball is partially positioned over or within the detent, the spring can act to promote the ball being properly received in the detent. That is, the pressure of the ball against an edge of the detent serves to direct the reversing lever towards or to one of the proper, predetermined positions. However, due to the small size of the components, the ball must be nearly in the proper position for this to have any effect. More broadly, if the ball is not positioned nearly in the proper position, the spring pressure has no effect.
One of the important aspects of these types of tools is manufacturing complexity and costs. In using these ball/detent features, the manufacturing complexity and costs are increased. As an example of this, the spring is first inserted into a blind hole formed either in the tool head or in the reversing mechanism, and then the ball is positioned on the end of the spring prior to assembly with the other components. In high speed manufacturing operations, ensuring the ball remains in the proper place as the spring is compressed to allow the other components to be assembled is no small endeavor.
In another aspect of manufacturing costs and complexity, internal components are often utilized that allow one or more other components to be properly located. If these internal components are to be fixed in a specific position, it is common to have to provide a mechanical attachment such as screws.
Accordingly, there has been a need for an improved dual pawl mechanism and reversing method.
In accordance with an aspect, a reversible ratchet device such as for a reversible wrench is disclosed including a ratchet body having a cavity therein, the ratchet body having a first side with a first body opening communicating with the cavity, a ratchet assembly received by the cavity through the first body opening, the ratchet assembly including a ratchet gear having a drive portion engageable for transmitting torque from operation of the device, the ratchet assembly also including a pawl mechanism having at least one pawl selectively engageable with the ratchet gear for a selected drive direction, a cover plate attachable to the first side for closing the cavity, a spring, a ball biased by the spring, and a reversing lever operably coupled with the pawl mechanism for selecting the drive direction, the reversing lever having a first recess for receiving the spring-biased ball in a first lever position corresponding to a first drive direction, and having a second recess for receiving the spring-biased ball in a second lever position corresponding to a second drive direction, and the reversing lever having a raised portion between the first and second recesses, the raised portion including a peak and first and second ramps leading from the peak to the first and second recesses respectively.
The first and second ramps may be generally linear.
The reversible ratchet device may further include a portion stationary relative to the ratchet body, the bore being formed in the stationary portion, the spring being received within the bore, the ball being partially received within the bore and partially extending from the bore when the reversing lever is in the first or second lever positions. The reversing lever may further include first and second stops formed thereon, the first and second recesses disposed between the first and second stops. The first stop may be disposed proximate the first recess, the second stop may be disposed proximate the second recess, rotation of the reversing lever between and to the first and second lever positions forces the ball towards the bore to compress the spring therein, and rotation beyond the first and second lever positions brings the reversing lever stops into contact with the stationary structure, the stationary structure thus restricting appreciable rotation of the reversing lever beyond the first and second lever positions.
The stationary structure may be a spacer disposed between the reversing lever and the cover plate. The spacer may be received by the cavity through the first body opening, the cavity and spacer having complementary structure for defining the position of the spacer within the cavity, and the assembled cover plate preventing appreciable movement of the spacer from the cavity. The bore is may be a throughbore having a first bore opening assembled proximate the reversing lever and a second bore opening assembled proximate the cover plate, the ball being inserted into the throughbore through the second bore opening to be proximate the reversing lever at the first bore opening, and the spring being inserted into the throughbore through the second bore opening to be proximate the cover plate at the second bore opening.
In another aspect, a reversible ratchet device such as for a reversible wrench is disclosed including a ratchet body having a cavity therein, the ratchet body having a first side with a first body opening communicating with the cavity, a ratchet assembly received by the cavity through the first body opening, the ratchet assembly including a ratchet gear having a drive portion engageable for transmitting torque from operation of the device, the ratchet assembly also including a pawl mechanism having at least one pawl selectively engageable with the ratchet gear for a selected drive direction, a cover plate attachable to the first side for closing the cavity, a reversing lever operably coupled with the pawl mechanism for selecting the drive direction, the reversing lever having first and second recesses and being movable between and to first and second lever positions corresponding to respective first and second drive directions, a spring, a ball biased by the spring into the reversing lever first recess in the first drive direction and biased by the spring into the reversing lever second recess in the second drive direction, and a throughbore having a first bore opening proximate to the reversing lever and a second bore opening distal to the reversing lever, the ball being inserted through the second bore opening to be disposed in biased contact with the reversing lever at the first bore opening, and the spring being inserted into the second bore opening after the ball is inserted therein.
The cover plate may be assembled proximate the second bore opening, and the spring may be compressibly disposed between the cover plate at the second bore opening and the ball. The reversible ratchet device may further include a spacer having the throughbore formed therein for receiving the ball and the spring. The spacer and the cavity may have complementary structure for defining the position of the spacer within the cavity, and the assembled cover plate prevents appreciable movement of the spacer from the cavity.
The reversing lever may include a raised portion between the first and second recesses, the raised portion including a peak and first and second ramps leading from the peak to the first and second recesses respectively. The reversing lever may include first and second stops, the first and second recesses generally disposed between the first and second stops. The ball may be partially received within the throughbore and may partially extend therefrom when the reversing lever is in the first or second lever positions. The first stop may be disposed proximate the first recess, the second stop may be disposed proximate the second recess, rotation of the reversing lever between and to the first and second lever positions forces the ball towards the bore to compress the spring therein, and rotation beyond the first and second lever positions brings the reversing lever stops into contact with the stationary structure, the stationary structure thus restricting appreciable rotation of the reversing lever beyond the first and second lever positions.
In another aspect, a reversible ratchet device such as for a reversible wrench is disclosed including a ratchet body having a cavity therein, the ratchet body having a first side with a first body opening communicating with the cavity, a ratchet assembly received by the cavity through the first body opening, the ratchet assembly including a ratchet gear having a drive portion engageable for transmitting torque from operation of the device, the ratchet assembly also including a pawl mechanism having at least one pawl selectively engageable with the ratchet gear for a selected drive direction, a cover plate attachable to the first side for closing the cavity, a spring, a ball biased by the spring, and a reversing lever operably coupled with the pawl mechanism for selecting the drive direction by rotation of the reversing lever between and to first and second lever positions, the reversing lever having a first recess for receiving the spring-biased ball in the first lever position corresponding to a first drive direction, and having a second recess for receiving the spring-biased ball in the second lever position corresponding to a second drive direction, the reversing lever further including first and second stops limiting rotation of the reversing lever appreciably beyond the first and second lever positions, the first and second recesses being formed generally between the first and second stops.
The spring and ball may be disposed within a bore, and the ball may be partially received within the bore and partially extends therefrom in contact with the reversing lever when in the first and second lever positions. The reversible ratchet device may further include a structure stationary relative to the ratchet body, the first stop being disposed proximate the first recess, the second stop being disposed proximate the second recess, and rotation of the reversing lever beyond the first and second lever positions brings the stops into contact with the stationary structure to prevent appreciable rotation of the reversing lever beyond the first and second lever positions.
In a still further aspect, a reversible ratchet device such as for a reversible wrench is disclosed including a ratchet body having a cavity therein, the ratchet body having a first side with a first body opening communicating with the cavity, a ratchet assembly received by the cavity through the first body opening, the ratchet assembly including a ratchet gear having a drive portion engageable for transmitting torque from operation of the device, the ratchet assembly also including a pawl mechanism having at least one pawl selectively engageable with the ratchet gear for a selected drive direction, a cover plate attachable to the first side for closing the cavity, a reversing lever operably coupled with the pawl mechanism for selecting the drive direction, and a spacer between the reversing lever and the cover plate, the cavity having a structure complementary to the spacer for defining the position of the spacer within the cavity.
The assembled cover plate may be proximate to the spacer to prevent appreciable movement of the spacer from the cavity. The reversing lever may include a pivot extension, and the spacer may include a pivot recess for receiving the pivot portion.
The reversible ratchet device may further include a ball and a spring, wherein the spacer includes a throughbore having a first bore opening proximate the reversing lever and a second bore opening proximate the cover plate when assembled, the throughbore receiving the ball therein through the second bore opening and receiving the spring therein through the second bore opening, the spring biasing the ball against the reversing lever proximate the first bore opening.
3;
Referring initially to
The ratchet head 10 is of a type of ratchet known as a dual-pawl ratchet wrench allowing a user to selectively determine a torque direction. More specifically, the ratchet head 10 includes first and second pawls 20, 22 that are selectively engaged with a ratchet gear 24, the ratchet gear 24 being operatively engageable with the working piece. When the first pawl 20 is engaged with the ratchet gear 24, torque drive is permitted with rotation of the ratchet head 10 in a first rotational drive direction while slippage occurs with rotation of the ratchet head 10 in a second rotational drive direction opposite the first. Conversely, when the second pawl 22 is engaged with the ratchet gear 24, the first pawl 20 moves out of engagement with the ratchet gear 24, and torque drive is permitted with rotation of the ratchet head 10 in the second drive direction while slippage occurs in the first drive direction.
As can be seen, the cavity 16 includes several portions for receiving and retaining the components therein. The ratchet gear 24 is received in a first large generally circular portion of the cavity 16, referred to herein as the drive cavity 26. The ratchet gear 24 has a generally circular body portion 28 with ratchet gearing or teeth 30 on a circumferential surface 32 and has an upstanding drive post 38, which may be a drive square. The ratchet teeth 30 engage with pawl teeth 40 formed on the pawls 20, 22 for selective engagement with the pawls 20, 22 to provide drive through the drive post 38. As shown in
The pawls 20, 22 are located in a further portion of the cavity 16, referred to herein as the pawl cavity 60, and the drive cavity 26 and pawl cavity 60 are overlapping or communicating to permit the pawls 20, 22 to move into and out of engagement with the ratchet teeth 30 of the ratchet gear 24.
As will be discussed in greater detail below, an actuator for selectively engaging and dis-engaging the pawls 20, 22 with the ratchet gear 24 is provided, referred to herein as a reversing lever 70. The reversing lever 70 is received in a further circular cavity portion of the cavity 16, referred to herein as the actuator cavity 72 (
As described, the reversing lever 70 is selectively positioned to select one of the pawls 20, 22 for selecting a drive direction. In order to effect this selection, the reversing lever 70 includes a reversing disc portion 90, below which the seal 78 is compressed. Each of the pawls 20, 22 has a selector post 100 for being manipulated by the reversing disc portion 90. More specifically, the reversing disc portion 90 has a recess 102 defined by a surface 104 and by hooks 106. With reference to
As noted above, a spacer 140 is provided to position the reversing lever 70. In greater detail, the reversing lever 70 is positioned between the ratchet body 14 and the spacer 140, and the spacer 140 abuts a bottom side of the cover plate 50. The spacer 140 includes a recess 142 into which a portion of the reversing lever 70 is received. This portion is an upstanding post 144, forming a pivot, with a generally circular geometry (
The ratchet head 10 is preferably designed to promote a tactile feel for a user to identify when the reversing lever 70 is in a proper position for the two drive directions. Towards this end, a ball and detent structure are provided, as is common in devices of this type. More specifically, the spacer 140 has a throughbore 150 (
As best seen in
With the reversing lever 70 in an initial position with the ball 112 positioned in a first of the troughs 116, the reversing lever 70 may be rotated thereby forcing the ball 112 to ride up one of the ramps 162 and forcing the spring 156 to compress. Once the ball 112 passes over the meeting point or peak 166 where the ramps 162 meet, the spring 156 provides a bias to advance the reversing lever 70 towards a second of the troughs 116. When the ball 112 is aligned with one of the troughs 116, the ball 112 at least partially extends from the spacer throughbore 150. Each of the troughs 116 is partially defined or shaped with a wall portion 168 extending upwardly with which the ball 112 comes into contact when the reversing lever 70 has reached the proper position.
The spacer 140 is easily mounted in the ratchet body 14. The spacer 140 includes at least one and preferably two portions 170 having complementary shapes to portions of the ratchet body 14 so that the spacer 140 may be assembled easily, such as in a linear fashion, into a defined position. In the present form, the spacer portions 170 are in the form of partially circular wings or ears that are received in ear recesses 172 formed to the sides of the actuator cavity 72. In this manner, the spacer 140 may be properly positioned easily, and the cover plate 50 abutting a top surface of the spacer 140 prevents the spacer 140 from moving from the assembled positioned, without the need for screws or other securements.
In order to promote the tactile feel for the user, as well as to promote rotation of a proper amount, a stop mechanism is provided. In the present form, this stop mechanism is provided by structure formed on the reversing disc portion 90 and the spacer 140. However, it should be noted that the structure may be provided on any portion of the components used for reversing the direction and on any portion of the components that remain relatively stationary when the reversing lever 70 is being moved. Here, the reversing disc portion 90 includes a first and second stops surfaces 120 formed proximate the troughs 116, as best seen in
It should also be noted that the ratchet head 10, as described, simplifies manufacturing costs and labor. The reversing lever 70 is inserted into the cavity 16 so that the lever portion 76 extends from the throughbore 74, and is sealed therewith by the seal 78. The ratchet gear 24 is inserted into the cavity 16 with the bearing portion 34 received in the recess 36. The pawls 20, 22 and the spring 107 therebetween are positioned within the cavity 16 between the reversing lever post 144 and the ratchet gear 24, and above the reversing disc portion 90, one of the pawl selector posts 100 being received by one of the hooks 106. The spacer 140 is inserted with the spacer depending portion 123 between the reversing lever stop surfaces 120, the ears 170 being received in the ear recesses 172. The ball 112 is inserted into the throughbore 150, and then the spring 156 associated with the ball 112. The cover plate 50 is then installed such as with the two screws 54. The spacer 150 is restricted from shifting upward by the cover plate 50, and from shifting downward by its cooperation with the reversing lever post 144. Generally, the design of the ratchet head 10 serves to retain and position each component with the ratchet body 14, with the cover plate 50, or through cooperation with one of the other components, thus minimizing the use of screws or other securements, for instance, and other manufacturing steps common to assembling dual ratchet wrenches.
While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims.
The present application is a continuation of U.S. Ser. No. 11/726,262 filed Mar. 21, 2007, the filing priority of which is claimed and the entire disclosure of which is hereby incorporated by reference.
Number | Name | Date | Kind |
---|---|---|---|
6513409 | Lee | Feb 2003 | B1 |
7111527 | Lee | Sep 2006 | B1 |
7121169 | Larson | Oct 2006 | B1 |
7299720 | Schultz et al. | Nov 2007 | B1 |
Number | Date | Country | |
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20130283982 A1 | Oct 2013 | US |
Number | Date | Country | |
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Parent | 11726262 | Mar 2007 | US |
Child | 13927301 | US |