This application relates to hand tools and, more particularly, to ratcheting wrenches. Ratchet wrenches have been provided generally with multiple elements, such as pawls and levers, located in the head of the wrench to permit ratcheting and to control direction. These constructions generally require complex assembly and manufacturing processes. For example, a common type ratchet wrench, such as Snap-on, Inc., model no. F872 round head ratchet, provides for selective ratcheting in either direction. The wrench includes cam surfaces of the pawl that are designed to allow for tightening of a socket while the cam is in a first position allowing rotation only in one direction, such as clockwise. When the wrench is rotated in a counterclockwise direction a gear rotates and ratchets.
Wrenches that provide large amounts of torque that are made of few components have been known. Examples are strap wrenches, ratcheting tube wrenches and pipe wrenches. Such wrenches may have pivots which require the wrench to be assembled of more than one piece. Also, wrenches such as strap wrenches require adjustment of the straps generally in order to provide sufficient amounts of torque. In addition, such wrenches are not easily manufactured through automated manufacturing processes.
Also such wrenches do not provide a proper geometry and construction to allow for the teeth or serrations in the head of the wrench to provide for dual functionality of torquing and also ratcheting. Generally, serrations that provide for torque must be large in order to take up the hoop stress imparted during torquing. Serrations that provide for ratcheting are generally small to allow for low torque so that the teeth may move on and off the corner of a fastener. No known wrenches provide a proper geometric construction that provide for serrations that have dual functionality of torquing and ratcheting. Therefore, a wrench is desired that has one major piece and provides for ratcheting and/or release of the fastener during non-torquing rotation.
In an embodiment, a wrench is provided comprising a first end including a handle, a second end including a flexible ring having an inner surface having serrations and the flexible ring having an attached end integrally formed with the handle and a free end defining a pawl. The flexible ring may have flexibility and resilience such that when the wrench is rotated in a torquing direction the flexible ring flexes inwardly from a rest, unstressed position and wraps down on the fastener. When the wrench is rotated in a non-tightening direction, the flexible ring flexes outwardly from the rest position to allow the serrations to ratchet around the fastener. The attached end of the ring is coupled to the handle at a tensile load bearing portion and adjacent the tensile load bearing portion is a shoe which forms an arc that may abut the pawl. The shoe may provide a self energizing force against the pawl. The arc of the shoe may be eccentric relative to the arc formed by the outer surface of the ring, the arcs respectively having center points B and A, such that radii to the center points from a common point C cooperate with a line joining the centers to form an oblique triangle.
When the wrench is oriented in a rest condition so that the free end of the ring is located at about a six o'clock position with the handle down, and the center point A is located at the center of the ring, the center point B of the shoe arc is offset from center point A, being disposed between about the one o'clock and two o'clock positions. In an embodiment, the ring may include from about 6 to about 36 teeth forming serrations. In an embodiment where the wrench is ¾″ nominal size, the ring may have 30 teeth. In an embodiment, a slit may be formed in the handle between the tensile load bearing portion and the shoe. The slit may have a hole formed at its closed end wherein the slit and the hole provide strain relief.
In an embodiment, the attached end of the ring may be attached to the handle at a tensile load bearing portion and adjacent the tensile load bearing portion is a shoe having an arcuate surface that may form an arc upon which the pawl may abut, and a slit may be formed in the handle between the tensile load bearing portion and the shoe. The slit may have a hole formed at its closed end wherein the slit and the hole provide a strain relief. In an embodiment, a gear insert may be located within the ring. The gear insert may include an outer surface having serrations adjacent to the serrations of the inner surface of the ring. The serrations of the outer surface may correspond in size and number to the serrations of the ring wherein, upon movement of the wrench in a non-tightening direction, the gear insert will ratchet relative to the gear insert. The gear insert may include a rim that rides on a shoulder of the ring, being held in place by a retaining ring. In an embodiment, the gear insert may be one piece and may be retained axially to the ring by a single retaining ring and resting in circumferential grooves present in both the gear insert and the ring at a midpoint of each of the gear insert and ring. The gear insert may include a torquing surface serration pattern on its inner surface. In an embodiment, the gear insert may include a hex torquing surface. In an embodiment the gear insert may include a double hex serration pattern on its inner surface. The gear insert may include one more serration on its outer surface than the number of serrations on the ring. The gear insert may be one piece.
In an embodiment, a method of manufacturing a wrench is provided comprising the steps of forming a one-piece wrench of steel having a handle and a solid disk integrally formed with the handle, removing a central portion of the disk to form a ring, heat treating the wrench and forming a free end of the ring by cutting an arc shaped separation and gap between the handle and the ring adjacent the gap to form a shoe on the handle and a pawl on the ring. The separation may be 0.010 inch. The steel in an embodiment may be 50 B 44 material. In an embodiment the method further comprises the steps of forming teeth in the solid disk by drilling and broaching prior to the heat treating. In an embodiment the method further comprises the steps of cutting by wire EDM, laser, water jet saw or other narrow slit-forming process. In an embodiment the material used may be composite including fiber reinforced plastic.
In an embodiment, a one-piece wrench is provided comprising a first end having a socket having, along an inner surface, means for applying torque, a pawl means for ratcheting against a fastener located within the socket and a self energizing means wherein, upon rotation of the wrench in a tightening direction, the socket will clamp down on a fastener. The torque applying means may include serrations on the socket. The self energizing means may include a resilient ring forming the socket, the ring having a free end that allows the ring to clamp down on the fastener. The pawl means may include the free end of the flexible ring having serrations thereon. The self energizing means may include a handle having a shoe engageable with the pawl means to urge the pawl means against a fastener located therein. In an embodiment the self energizing means may include a handle having a shoe that abuts against the pawl means constricting the pawl against a fastener located therein. The self energizing means may include an arc formed on a shoe having a center point that is offset from a center point of an arc formed on a flexible ring constructed adjacent the shoe.
In an embodiment, a wrench is provided comprising a handle and a flexible and resilient split ring having a mounting end integral with the handle and a free end defining a pawl, the pawl having an inner surface with serrations thereon. In an embodiment a gear insert may be mounted within the split ring. The gear insert may have a torquing surface on its inner diameter and serrations on its outer surface corresponding to the serrations on the pawl inner surface. In an embodiment a slit may separate the free end of the split ring from the handle where a first arcuate surface is formed by the split ring at the slit and a second arcuate surface is formed by the handle at the slit. In an embodiment the first arcuate surface is eccentric to the second arcuate surface and may provide a self-energizing force for the wrench. In an embodiment the first arcuate surface is concentric to the second arcuate surface and provides a self-energizing force for the wrench. In an embodiment the slit is formed generally along a radius that defines an outer edge of the split ring. In an embodiment the slit is formed generally offset from a radius that defines an outer edge of the split ring.
In a further embodiment a wrench is provided comprising a handle and a flexible and resilient split ring having a mounting end integral with the handle. The ring may have a free end at which it is split from the handle. A gear insert may be mounted within the ring. The gear insert may include a torquing inner surface and an engagement feature along its outer surface. In an embodiment the free end of the ring may be separated by a slit from a shoe on the handle. In an embodiment the split ring, shoe and slit are oriented in order to provide a self-energizing wrench that upon torquing will wrap down on a fastener located within the split ring. In an embodiment torque capacity provided by the engagement feature is greater than the torque capacity provided by the slit. In an embodiment the engagement feature includes serrations. In an embodiment the engagement feature includes a chamfered circumferential recess for receiving a chamfered circumferential projection on the ring inner surface. In an embodiment the engagement feature includes a chamfered circumferential projection protruding into a chamfered circumferential recess on the ring inner surface. In an embodiment the engagement feature includes a chamfered circumferential recess corresponding to a chamfered circumferential recess on the ring inner surface and a wire ring in compression therebetween. In an embodiment the engagement feature comprises a fluid having a high coefficient of friction.
For the purpose of facilitating an understanding of the ratchet wrench, there is illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, their construction and operation, and many of their advantages should be readily understood and appreciated.
Referring to
The ring 30 includes an attached end 38 and a free end 40. The free end 40 of the ring 30 defines a pawl 42. The pawl 42 is constructed at the free end 40 of the ring 30 in order to provide a restoring force for the pawl spring arm. Adjacent to the pawl is a shoe 50 which has an arcuate surface 54 and a toe 55. The shoe 50 is separated from the pawl 42 by a slit 52. The attached end 38 of the ring 30 is attached to the handle 20 at a tensile load bearing portion 60. The tensile load bearing portion 60 is spaced from the free end 40 of the ring 30 by a gap 62. Therefore, it can be seen that the top or working end of the handle defines the shoe 50 and the tensile load bearing portion 60.
In order for the wrench 10 to have the proper construction providing for a self energizing clamping motion of the flexible ring 30 so that, upon tightening, it will wrap down on a fastener 90 (see
In an embodiment, a wrench is provided that has a self-energizing ring 30 that also has a pawl with low ratcheting torque when the orientation of points A, B and C form an oblique or acute triangle. In an embodiment, the lines between A and B and A and C represent a portion of the compression force and the line between B and C represents the tensile force between the ring 30 and the shoe 50. Maintaining this geometry provides a self-energizing force for the wrench. The self-energizing effect includes the shoe 50 acting against the resilient and flexible ring 30 causing the ring diameter to be reduced and results in the ring 30 wrapping down on a fastener. The width of the ring 30 is also an important factor in providing for a ring 30 that is sufficiently flexible and resilient to allow for self energizing and ratcheting functions. In an embodiment, the width of the ring 30 measured radially from the root of a tooth 15 to the outer surface 32, is approximately between 0.055 and 0.077 inches in a steel ¾″ wrench. Another important feature is the number and size of the teeth 15 within the ring 30. In an embodiment twenty-four (24) teeth may be provided having a circular pitch of about ⅛″ in a steel ¾″ wrench.
Therefore, it may be understood that the wrench disclosed herein provides for a wrench head that is self energizing. The self energizing function is facilitated in an embodiment by the flexible ring 30 having an arc with a center point A and a shoe having an arc with a center point B. The orientation of the shoe arc 52 to the ring arc 32 is important in providing for a self energizing means. In an embodiment the shoe arc 52 and ring arc form tangents that meet at point D as shown in
The operation of the wrench will now be described with reference to
During constriction of the flexible ring 30 the separation slit 52 will narrow and the shoe arcuate surface 54 will abut against and drive the pawl portion 42 of the flexible ring 30 against the fastener 90. Upon full torquing in an embodiment (for a ¾ inch wrench) the shoe 50 may move 0.030 inches from its resting position generally tangentially around the ring 30. The toe 55 of the shoe 50 moves in a clockwise direction and at least partially toward the ring 30. Simultaneously the pawl 42 will slide along the arcuate surface 54 of the shoe 50 and close the gap 62, causing the ring 30 to clamp down on the fastener 90. In other embodiments a wrench may be provided wherein the shoe 50, upon full torquing may move by various amounts from the shoe's resting position and not close the gap 62.
When the wrench is turned in a counterclockwise (non-torquing) direction in the embodiments shown in
In an embodiment, the wrench 10, 100, 200, 300, 400, 500 may be manufactured according to the following process. A one-piece forged wrench is provided having a first end including a handle to a second end including a solid disk. A central portion of the disk is removed to form a hole that defines the ring 30 by drilling and broaching. In an embodiment the hole that is broached is circular in shape. In an alternate embodiment the shape may be any form that provides for a pre-load on the gear insert 210 when mounted in the hole. For example, the hole may be oval. The wrench is formed of steel. In an embodiment, 50 B 44 steel is used. However, any steel providing the proper flexibility and strength may be used. The wrench is then heat treated. After cooling, the wrench in an embodiment is then placed in a wire EDM (electrodischarge machining) machine. A cut is made to form the separation slit 52 and the gap 62 forming the free end 42 of the ring 30 and separating it from the shoe 50. The cut is made from the outside of the handle toward the inside of the handle toward gap 62. In an embodiment, the cut is 0.010 inches wide. In an embodiment the cut is widened at the gap 62. In an embodiment, the wire EDM machine is fitted so that wrenches may be manufactured in multiple batches one after another. In an embodiment the cutting may also be accomplished by a laser, water jet, saw or other narrow slit-forming processes. The process may be further automated by use of pick and place machinery to quickly load and unload wrenches to be cut.
Referring to
The gear insert 210 has along its inner surface a double hex pattern 250. In an additional embodiment the gear insert 210 may be a solid disk having a square drive protruding from its center so that the wrench can function as a ratchet head. It may be understood that all such embodiments of the gear inserts 210 may be used interchangeably on the same wrench 10, 100, 200, 500 (discussed below). The wrench 10, 100, 200, 500 may also be provided with interchangeable gear inserts 210 having multiple sized hex inner surfaces 250. In this way, a single wrench 200 may be used to tighten or loosen multiple fastener sizes. In an embodiment, the gear insert may be formed of steel 50 B 44. In alternative embodiments the insert 210 may be other metal composite, polymer or resin materials sufficient to provide durability and limited resiliency.
The wrenches 200, 300 operate in a similar fashion as the one-piece wrenches discussed previously, in that upon rotation in a clockwise tightening direction, the flexible ring 30 will wrap down against the gear insert 210, 270 causing serrations 234 to engage corresponding serrations 240 and prohibit the gear insert 210, 270 from rotating relative to the ring 30. The torquing surface or double hex 250 of the gear insert 210, 270 will engage the corners of a fastener and provide for tightening. Where additional torque is required to tighten, the ring 30 continues to wrap down tightly against the gear insert 210, 270 where the serrations 234 tightly engage serrations 240 of the gear insert 210, 270 and the free end 42 moves into the gap 62. In an embodiment, the ring outer surface 32 may be eccentric or concentric to the arcuate surface 52 of the shoe 50 (
Similar to the functioning described above, upon rotation in a counterclockwise direction, the flexible ring 30 will unwrap from the gear insert 210, 270 and the serrations 234 of the ring 30 will separate slightly from the serrations 240 of the gear insert and allow for a ratcheting between the serrations 234 and 240. The pawl 42 has a restoring force and flexes away from the gear insert 210, 270 and the serrations 234 of the pawl 42 move on and off of the serrations 240 of the gear insert 210, 270 as the pawl 42 slides back and forth adjacent the shoe 50. Therefore, it may be understood that the wrench may be easily moved between a clockwise tightening rotation and counterclockwise ratcheting rotation in order to tighten down a fastener in a rapid sequence.
In order to loosen a fastener 90, any of the wrenches 10, 100, 200, 300, 400, 500 is flipped over to its opposite side and loosening is provided in the counterclockwise direction and ratcheting in the clockwise direction.
The engagement feature 550 of the wrench 500 may be formed according to many structures that provide for the engagement of two side-by-side members and will allow insert 510 to rotate within flexible ring 30 and free end 40 to withdraw from the insert 510. For example, the engagement feature 550 provided by the previous embodiments were serrations 234, 240 (
Turning to
Turning to
For all embodiments shown in
When the wrench 500 is rotated in a non-torquing direction the ring 30 un-wraps (as has been discussed for previous embodiments) and the projection 551, 551′, 558 withdraws from the recess 552, 552′, 553, 554 reducing torque allowing the wrench 500 to rotate in one direction while the insert 510 remains stationary with the fastener located therein. Therefore the wrench 500 may not necessarily have a pawl (see pawl 42 of
When the wrench is turned in a counterclockwise (non-torquing) direction in the embodiment shown in
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 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 applicants' contribution.
This application claims the benefit of the earlier filing date of provisional application Ser. No. 60/349,201, filed Jan. 16, 2002.
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Number | Date | Country | |
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60349201 | Jan 2002 | US |