Patent Publication Number: US-5829326-A

Title: Cover plate for a ratchet wrench

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to ratchet wrenches, and more particularly, to a cover plate which is retained on the wrench without screws or retaining rings. 
     Cover plates are used on ratchet wrenches to minimize the infiltration of dirt into the opening in the head of the wrench in which the drive gear and pawl are located. The usual means to retain the cover plate on the wrench is by screws which extend through the cover plate or by one or more retaining rings which are disposed over the cover and are secured to the head of the wrench. These require a multiplicity of parts and assembly time and contribute to the overall costs of the ratchet wrench. 
     The applicant is unaware of any cover plates having gripping segments to retain the cover plate in the head of the ratchet wrench. In U.S. Pat. No. 5,406,876 Harless et al disclose a munitions store retention and release system wherein a plurality of integral, circumferentially spaced resilient, locking fingers have terminal projections, extending radially inwardly. The locking fingers are engaged by a lug and urged radially into their associated windows until the terminal projections on the fingers firmly engage the annular groove on the lug, thus securing the store to the rack. 
     In U.S. Pat. No. 5,474,124 Samuels discloses a wellhead retrieval tool assembly wherein a check valve has a spear formed as a solid ring at the bottom with free fingers extending upward. The fingers are resilient and have protrusions adapted to engage a retrieval groove in the check valve. 
     Chase et al in U.S. Pat. No. 5,498,008 disclose a chuck jaw locking apparatus for a rotatable machine tool such as lathe wherein collet fingers are formed with enlargements at the ends of the fingers. A circumferential groove is formed having a registration shoulder for all the lock jaw segments, each of which has a protruding tab. 
     De Jong in U.S. Pat. No. 5,503,446 discloses a device for gripping and handling objects such as compact discs wherein gripping fingers can be displaced from each other in a radial direction of a hole to be engaged. 
     In U.S. Pat. No. 5,568,671 Harris et al disclose a caster assembly with an integral plastic stem and horn and with a removable axle lock cap wherein the horn sidewalls have fingers forming slots receiving grooved end portions of the axle. 
     In U.S. Pat. No. 5,638,577 Gooding et al disclose an automobile jack handle having a retainer sleeve with integral prong elements in one elongated rod section that are selectively engaged and disengaged from cooperation with an integral retention collar in another retention cooperating rod section. 
     Thus, there is a need for a simple, inexpensive cover plate for use with ratchet wrenches. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an inexpensive cover plate for the opening in the head of a ratchet wrench which has a minimum number of parts and can be installed with minimum labor. 
     In accordance with the teachings of the present invention, there is disclosed a cover plate for use with a ratchet wrench. The ratchet wrench has a head portion having an opening formed therein, the opening having a channel formed peripherally therein. The cover plate includes a body having an upper surface and a lower surface. A plurality of spaced-apart segments are formed on the lower surface of the body and extend substantially perpendicularly thereto and away from the upper surface. Each segment has an end distal from the lower surface. A respective protrusion is formed on the end of each segment. Each protrusion has a portion chamfered outwardly from the end of the respective segment toward the lower surface. Each protrusion has a step formed thereon, the step being oriented toward the lower surface. When the lower surface of the body of the cover plate is disposed in the opening in the head of the ratchet wrench, the chamfered portion of each segment is directed into the channel. The step on each segment is locked in the channel, wherein a seal is formed between the cover plate and the head of the ratchet wrench and preventing the infiltration of dirt into the opening in the head of the wrench. 
     A method of covering the opening in the head of a ratchet wrench is further disclosed. 
     These and other objects of the present invention will become apparent from a reading of the following specification taken in conjunction with the enclosed drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the bottom of a ratchet wrench showing the cover plate of the present invention installed thereon. 
     FIG. 2 is a top plan view of the cover of the present invention for the ratchet wrench. 
     FIG. 3 is a side elevation view of the present invention. 
     FIG. 4 is a bottom plan view of the present invention. 
     FIG. 5 is a cross-sectional view taken across the lines 5--5 of FIG. 2. 
     FIG. 6 is a perspective view showing the cover plate of the present invention prior to insertion into the opening in the head of the ratchet wrench, the drive gear not being shown. 
     FIG. 7 is a side elevation view of the head of the ratchet wrench showing, in broken lines, the opening and the channel within the head of the wrench. 
     FIG. 8 is a cross-sectional view showing the cover plate of the present invention being inserted into the opening in the head of the ratchet wrench. 
     FIG. 9 is an enlarged cross-sectional view showing the chamfered edge of the segment directing the segment into the opening and showing flexing of the segment. 
     FIG. 10 is an enlarged cross-sectional view showing the cover plate partially inserted into the opening and the segment flexed. 
     FIG. 11 is a cross-sectional view showing the cover plate of the present invention locked in the channel within the opening in the head of the ratchet wrench. 
     FIG. 12 is an enlarged cross-sectional view showing the step on the segment locked in the channel in the opening. 
    
    
     DESCRIPTION 
     Referring now to FIGS. 1-12, the ratchet wrench 10 has an opening 12 formed therein in which there is mounted a gear drive (not shown) and a pawl (not shown). The cover plate 14 of the present invention is shown in FIG. 1 mounted flushly on the ratchet wrench and covering the opening 12. 
     As shown in FIGS. 2-5, the cover plate 14 has a body 16 with an upper surface 18 and an opposite lower surface 20. A through opening 22 is formed between the upper surface 18 and the lower surface 20. A plurality of spaced-apart segments 24 are formed peripherally on the lower surface 20 of the body 16. Each segment 24 has an end 26 distal from the lower surface 20. Each segment 24 further has a protrusion 28 formed on each respective end 26, the protrusion 28 being oriented outwardly from the opening 22 in the cover plate 14. Each protrusion 28 further has a chamfered portion 30 which is formed outwardly from the end 26 of the respective segment 24 toward the lower surface 20 of the body 16. Each segment further has a step 32 formed thereon. The step 32 is oriented with a planar surface oriented toward the lower surface 20. It is preferred that the planar surface of the step 32 be approximately parallel with the lower surface 20 of the body 16. The segments 24 are disposed on the lower surface 18 in an order to correspond with the contour of the opening 12 in the head of the ratchet wrench. 
     The opening 12 in the head of the ratchet wrench 10 may be in the form of two overlapping circles in which the drive gear and the pawl are disposed or may be in any other configuration known to persons skilled in the art and appropriate to the particular ratchet wrench. Peripherally within the opening 12, there is formed a receiving means such as a channel 34 as shown in FIG. 7. Preferably, the channel 34 is near the edge of the opening 12, close to the outer face of the head of the ratchet wrench 10. 
     The opening 12 in the head of the ratchet wrench 10 is covered by placing the cover plate 14 adjacent to the opening 12 with the lower surface 20 of the body 16 directed toward the opening 12 (FIG. 6). The drive tang 36 on the gear drive (not shown) is received in the opening 22 in the cover plate 14. The cover plate 14 is inserted into the opening 12 in the ratchet wrench wherein each protrusion 28 on the end 26 of each segment 24 is engaged by the receiving means 34 in the opening 12 in the head of the ratchet wrench 10. As shown in FIGS. 8-12, the chamfered portion 30 of each protrusion 28 rides over the edge of the opening 12 in the head of the wrench and is directed into the receiving means (i.e., the channel 34 in the head of the ratchet wrench). The chamfered portion 30 assists in directing each segment 24 into the channel 34 and causes each segment 24 to flex inwardly (see arrow) toward the center of the body 16 (FIGS. 9 and 10). A ring 38 is formed around the opening in the cover plate 14 separated from the segments 24 by an annular groove 40. The amount of flexing of the segments 24 is limited by the width of the annular groove 40 such that the respective segments 24 may flex only to the extent that the segment 24 may contact the ring 38 and cannot flex additionally. In this manner, the segments 24 are prevented from being broken or damaged by overflexing. Continued insertion of the cover plate 14 into the opening 12 in the head of the ratchet wrench 10 causes the entire protrusion 28 of each segment 24 to be received within the receiving means 34 (FIG. 11). The step 32 on each protrusion 28 becomes locked in the channel 34 as each segment 24 springs back from the flexed position and the cover plate 14 is locked in the channel 34 (FIG. 12). The cover plate 14 forms a seal between the upper surface 16 of the cover plate 14, which is outside of the opening 12, and the outer surface of the head of the ratchet wrench 10. The upper surface 16 of the body 16 of the cover plate 14 is larger than the opening 12 in the head and the opening is entirely covered when the cover plate 14 is installed. Thus, the infiltration of dirt into the opening is virtually prevented. 
     It is preferred that the cover plate 14 be formed from corrosion resistant plastic. Thus, the segments 24 may flex and the entire cover plate 14 may be molded from a single unit to reduce costs in fabrication. As previously noted, no auxiliary components (e.g., screws, retaining rings) are required to retain the cover plate 14 to the head of the ratchet wrench. Thus, the number of parts is reduced as well as the labor costs in assembling the ratchet wrench. 
     Obviously, many modifications may be made without departing from the basic spirit of the present invention. Accordingly, it will be appreciated by those skilled in the art that within the scope of the appended claims, the invention may be practiced other than has been specifically described herein.