Patent Application
20070068346
The present invention relates generally to a pneumatic ratchet drive tool, and more particularly, to a pneumatic ratchet drive tool including a bit receiver defining a bit socket for receiving and temporarily retaining a bit.
Conventional pneumatic ratchet drive wrenches are typically used to fasten (and unfasten) fasteners that do not have cavities formed in their heads, but are instead adapted to be received in a socket of a tool, such as a ratchet. Such fasteners include, for example, hexagonal bolts and hexagonal nuts for being received in a hexagonal socket. The wrench typically includes a housing, a head extending axially from the housing, and a male socket fitting extending generally orthogonally from the head for mating with a socket or other tool. The male socket fitting is generally a square-shaped nub that is adapted to be received in an opening of the socket. Because the housing and the head are axially aligned and the male socket fitting extends generally orthogonally from the head of the ratchet, the ratchet can be employed in tight places where movement of the ratchet is restricted, such as in automotive repair and industrial applications.
Other types of fasteners have cavities formed in their heads for receiving a bit or head of a tool to fasten the fastener. Such fasteners include, for example, Phillips-head fasteners, slotted-head fasteners, and Torx® fasteners. Using a ratchet device to fasten these types of fasteners would be advantageous because of the compact design of the ratchet. However, conventional ratchets have only the male socket fittings for mating with sockets that receive heads of fasteners.
In one aspect of the present invention, a pneumatic ratchet drive tool generally comprises an elongate housing having first and second opposite ends and a longitudinal axis extending therebetween. An air inlet is disposed at the first end of the housing for connection to a source of pressurized air. A head extends generally axially from the second end of the housing. The drive tool comprises a ratchet mechanism, and a bit receiver extends from the head and is operatively connected to the ratchet mechanism. The bit receiver defines a bit socket for receiving and temporarily retaining a bit. The socket has a longitudinal axis generally orthogonal to the axes of the housing and the head.
Other objects and features will be in part apparent and in part pointed out hereinafter.
Corresponding reference characters indicate corresponding parts throughout the drawings.
Referring now to the drawings and particularly to
Referring to
The ratchet mechanism 26 generally includes a rotary wheel 51 sized to fit in the aligning openings of the yoke arms 45A, 45B and oscillating member 41. The rotary wheel 51 has a generally circumferential slot 53 in it extending through about half of the circumference of the rotary wheel. The bit receiver 21 extends laterally outward from the rotary wheel 51. Opposite the bit receiver 21 in the rotary wheel 51 is an axial bore 55 (
The ratchet mechanism 26 also includes a ratchet pawl, designated generally at 73, for controlling rotational direction of the bit receiver 21. The pawl 73 has a transverse bore 75 through it so that it can be mounted in the circumferential slot 53 in the rotary wheel 51 by way of inserting a pin 77 through the sides of the pawl and the sides of the rotary wheel. The pawl 73 has slanted or generally arcuate end parts as designated at 79 and 81. These portions have teeth that are configured to engage with the teeth on the inside of the opening 43 of the oscillating member 41. The pawl 73 has a groove or channel 83 formed in one longitudinal side for pivoting on the pin 77 when pushed by a free end 85 of the plunger, which is held against the pawl by the spring 69. Thus, it may be seen that by manually rotating the setting member 57 by means of the fingerpiece 65, the setting member shaft can be rotated angularly, which rotates the plunger 71 within the channel 83 of the pawl 73. In a first position, the pawl 73 is positioned to be rotated by the oscillating member 41 angularly in one direction (e.g., clockwise). In a second position, the pawl 73 is positioned to be rotated by the oscillating member 41 angularly in the opposite direction (e.g., counterclockwise). Each end of the ratchet pawl 73 operates only in one direction, and is free to move in a direction opposite to that direction.
The rotary wheel 51 is held in the yoke 47 of the head 5 on one side by a thrust washer 87, which is generally resilient and made of a spring material. The thrust washer 87 has waves, or bends in it in a circumferential direction so that it can be pressed between the rotary wheel 51 and yoke 47, holding them together. On the other side of the head 5, the rotary wheel 51 is held in place within the yoke 47 by a plate 89 and snap ring 91. The plate 89 has an extending circular boss 93, holding the snap ring 91, and a center bore 95 fitting over the bit receiver 21. The plate 89 fits into the opening of one arm 45B of the yoke 47 and is held in place by the snap ring 91 fit into an undercut 97 in the yoke arm opening. Spring loaded ball bearings (each designated generally by 99 and 101) apply force to hold the plate 89, thrust washer 87, and rotary wheel 51 in place. An example of similar pneumatic ratchets employing this type of ratchet mechanism is taught by co-owned U.S. patent application Ser. No. 10/938,312, the entirety of which is herein incorporated by reference.
In operation, the output shaft 47 rotates the crank shaft 24 and drive bearing 37, causing the oscillating member 41 to pivot about the longitudinal axis of the bit receiver 21. When oriented for turning the bit receiver 21 in a clockwise direction, the pawl is pivoted on plunger 71 so that pawl end part 81 engages the opening 43 of the oscillating member 41. The oscillating member 41 first moves clockwise when the crank shaft 24 and drive bearing 37 rotate. The teeth of the opening 43 of the oscillating member 41 engage the teeth of the pawl end part 81 and cause the rotary wheel 51 to rotate clockwise with the oscillating member. This also rotates the bit receiver 21 clockwise. After the crank shaft 24 rotates one half rotation (i.e., rotates 180°), the drive 37 causes the oscillating member 41 to reverse rotation and rotate counterclockwise. The teeth of the oscillating member's opening 43 disengage the teeth of the pawl end part 81 and slide past each other. Here, the rotary wheel 51 does not move. Once the crank shaft 24 rotates another one half rotation, the drive bearing 37 again causes the oscillating member 41 to reverse rotation back in a counterclockwise direction. This causes the teeth of the oscillating member's opening 81 to re-engage the teeth of the pawl end part 81 and rotate the rotary wheel 51, further turning the bit receiver 21 again. The process repeats until the motor is disengaged. Operation is similar for turning the bit receiver 21 in a counterclockwise direction, with the exception that the pawl end part 79 (instead of end part 81) engages the teeth of the oscillating member's opening 43 so that the bit receiver can be turned in the opposite direction (i.e., counterclockwise).
It is understood that the construction of the ratchet tool, more particularly the construction of the ratchet mechanism, for producing rotational movement of the bit retainer may differ from the illustrated embodiment without departing from the scope of this invention. For example, the ratchet mechanism may be similar to the mechanism disclosed in U.S. Pat. Nos. 6,578,643 and 6,860,174, both of which are herein incorporated by reference. Rotary wheel (i.e., ratchet wheel) of this specific type of ratchet mechanism includes teeth extending outward from the member around its full circumference that are engaged by a pair of pawls pivotally mounted on an oscillating member (i.e., rocker). Other types of ratchet mechanisms are within the scope of this invention.
Referring now to
The ratchet tool 10 includes a bit retainer 112 for temporarily retaining a bit 107 in the socket 105. In the illustrated embodiment, the bit retainer 112 is generally C-shaped and received within a channel-shaped recess 114 formed around the periphery of the bit receiver 21, as shown best in
In use, as the bit 107 is inserted to the socket 105, a tapered end of a bit contacts the engagement portion 121 of the bit retainer 112 and forces the engagement portion 121 substantially out of the socket and into its retracted position. As the bit 107 continues into the socket 105, a respective corner of the bit continues to contact the engagement portion 121 of the bit retainer 112. When the bit 107, and more specifically the body 109 of the bit, is fully received in the socket 105, the engagement portion 121 moves into its engagement position and the projecting portion is received in the slot 122 of the corresponding corner of the bit, such that the edges of the slot catch on the engagement portion to retain the bit in the socket. To remove the bit 107, the bit is pulled from the socket 105. As the bit 107 is pulled, the corner of the bit once again contacts the engagement portion 121 of the bit retainer 112, moving the bit retainer into its retracted position. Other ways of retaining the bit in the socket are within the scope of this invention.
When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
