There are a number of rotary impact tools in the prior art. These devices, often called impact wrenches, typically have an impact mechanism which generates a rotational movement by rapidly delivering a succession of rotational blows to a driven member. The driven member would typically have a drive end which is detachably engaged to a socket or other tool.

While the prior art impact wrenches will generally work for their intended purpose, the high torque applications in which these impact wrenches are used and the frequency with which these tools are used often place high stress on the drive end. Consequently, the drive end, at times, may fracture or deform. Since the drive end is an integral part of the impact wrench, the impact wrench is effectively disabled without a functioning drive end.

Consequently, the user is often left unable to complete a task when a drive end is broken.

Due to the complexity of the design of typical impact wrenches, repair of a disabled drive end is often only undertaken by manufacturer-trained technicians. In order to repair a drive end, the user must either send or deliver the broken impact wrench to the manufacturer or a repair center for repair, or else purchase a new impact wrench. The delay in repairing or replacing an impact wrench may significantly delay the completion of a task.

Summary of the Invention Generally, this application relates to an improved rotary impact tool which avoids the disadvantages of prior art tools while affording additional structural and operating

advantages.

An important feature is the provision of a rotary impact tool which is of relatively simple design and economical structure.

Another important feature is the provision of a rotary impact tool with an easily removable drive end.

Another important feature is the provision of a drive end that is easily detachable.

In connection with the foregoing features, yet another feature is the provision of a method of removing and replacing a drive end.

Brief Description of the Drawings For the purpose of facilitating an understanding of the subject matter sought to be protected, there is illustrated in the accompanying drawings an embodiment thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.

FIG. 1 is a fragmentary, sectional view of a rotary impact tool with a detachable drive end mechanism and retaining structure therefor; FIG. 2 is a reduced, side elevational view of the detachable drive end of the tool of FIG. 1; FIG. 3 is a front elevational view of a collar and a retaining clip of the tool of FIG.

1; FIG. 4 is a front elevational view of the rotary impact tool in FIG. 1 showing interaction between the retaining structure and the detachable drive end mechanism; FIG. 5 is an exploded, perspective view of the retaining structure and the detachable drive end mechanism of FIG. 1.

FIG. 6 is a view similar to FIG. 4 showing an alternate form of retaining structure; FIG. 7 is a fragmentary view similar to FIG. 1 of the retaining structure of FIG. 6; FIG. 8 is a view similar to FIG. 6 of another form of retaining structure; FIG. 9 is a view similar to FIG. 7 showing the retaining structure of FIG 8; FIG. 10 is a view similar to FIG. 6 of another form of retaining structure; FIG. 11 is a view similar to FIG. 7 of the retaining structure of FIG. 10; FIG. 11A is an enlargement of a portion of FIG. 11; FIG. 12 is a view similar to FIG. 6 of another form of retaining structure and drive end mechanism; FIG. 13 is a view similar to FIG. 12 of another form of retaining structure; FIG. 14 is a view similar to FIG. 12 of another form of retaining structure in a retaining condition; and FIG. 15 is a view similar to FIG. 14 showing the retaining structure in a release condition.

Detailed Description Referring to FIG. 1, there is illustrated a rotary impact tool 10 having a housing structure 11 which includes a housing 12, which may be formed of a suitable metal, or could be formed of a suitable plastic material, and defines an internal cavity. Disposed within the housing 12 is an impact mechanism 13 of known construction, which is coupled to a motor (not shown), the impact mechanism 13 typically including a hammer (not shown) and an anvil 14. Typically the hammer is driven by the motor for delivering repeated rotational impacts to the anvil 14, all in a known manner, for intermittently rotating the anvil 14. The anvil 14 has a splined end 15 which is disposed within and in

meshing engagement with the rear end of a splined sleeve 16 which is rotatably mounted within a bearing 17. The forward end of the housing 12 defines a cylindrical opening 18 into the cavity, in which is disposed an annular oil seal 18a which seats against the front ends of the splined sleeve 16 and the bearing 17. Formed laterally through the housing 12 adjacent to the front end thereof, are two apertures in the nature of cylindrical bores 19 which extend parallel to a diameter of the housing 12 on opposite sides thereof, intersecting the opening 18.

Referring also to FIGS. 2,4, and 5, the rotary impact tool 10 includes a detachable drive end mechanism which includes a drive end 20 which has a cylindrical body 21 with a drive square 22 projecting forwardly therefrom. Integral with the body 21 at the rear end thereof and extending laterally outwardly therefrom is an annular flange 23. Projecting rearwardly from the flange 23 is a reduced-diameter portion 24 provided at it's distal end with circumferentially spaced splines 25 designed for a mating engagement with the splines of the sleeve 16. In assembly, the splined end of the detachable drive end 20 is inserted into the housing opening 18, through the oil seal 18a and into meshing engagement in the front end of the splined sleeve 16, as can best be seen in FIG. 1, until the flange 23 seats against the oil seal 18a, which serves as a mechanical stop.

Referring also to FIG. 3, the detachable drive end mechanism includes an annular collar 31 having a cylindrical body 32. Formed in the outer surface of the body 32 at the front end thereof or two parallel flats 33 on opposite sides of the central axis and respectively defining co-planar shoulders 34 which lie in a plane perpendicular to the central axis. The collar 31 has an outer diameter slightly less than the diameter of the housing opening 18 and an inner diameter slightly greater than the outer diameter of the body 21 of the detachable drive end 20. In assembly, the collar 31 is fitted over the

forward end of the detachable drive end 20 and seated against the flange 23 of the detachable drive end 20. In this regard, a suitable annular groove 32a may be formed in the rear end of the collar 31 to accommodate the flange 23 (see FIGS. 1 and 5). A retaining structure 30 includes a clip 35 which may be formed of a flexible and resilient material, such as a spring steel or the like, having a bight 36 and a pair of legs 37 which converge slightly toward their distal ends, at which ends the legs are respectively provided with short outturned feet 38. In assembly, once the collar 31 has been installed in place, the legs 37 of the clip 35 are spread sufficiently to permit them to be respectively inserted into the lateral bores 19, so that the legs 37 respectively pass over the flats 33 of the collar 31 for engagement with the shoulders 34, until the bight 36 seats against the outer surface of housing 12 (see FIG. 4). The outturned feet 38 serve to frictionally hold the clip 35 in place in the lateral bores 19, the clip retaining the collar 30, which in turn retains the detachable drive end 20. For removal of the attachable drive end 20, the clip 35 is removed, permitting the drive end and the collar 31 to be pulled out of the tool.

Referring to FIGS. 6 and 7, there is illustrated an alternative embodiment of retaining structure, generally designated by the numeral 40. In this case, instead of parallel radial bores receiving a clip, there are formed in the housing 12, adjacent to the front end thereof, two diametrically aligned apertures in the form of radial bores 41. Also formed in the outer surface of the housing 12 and communicating with the bores 41 is an annular groove 42. Cylindrical retaining pins 43 are respectively inserted in the radial bores 41 to respectively seat on the flats 33 of the collar 31, each pin 43 having a length such that, when seated on the flat 33, it extends upwardly into the associated bore 41, the pins 43 being retained in place by an 0-ring 44 seated in the groove 42. In order to remove the detachable drive end 20, the 0-ring 44 is removed and the pins 53 are dropped out of the

radial bores 41, whereupon the drive end 20 can be grasped and pulled out along with the collar 31.

Referring to FIGS. 8 and 9, there is illustrated another embodiment of retaining structure, generally designated by the numeral 50. In this case, diametrically aligned bores 51 are formed in the housing 12 for respectively receiving pins 53. The pins 53 are respectively biased radially outwardly into the bores 51 by leaf springs 55, respectively disposed in front of the collar shoulders 34, with the opposite ends of each spring 55 respectively bearing against the ends of the associated collar flat 33. A similar retaining structure, generally designated 50a, is shown in FIGS. 10 and 11, the basic difference being that each pin 53 is provided with a radially outwardly projecting extension 56.

Referring to FIG. 11A, the pins 53 in both of the retaining structures 50 and 50a may be provided with a laterally outwardly projecting flange 54, which has a diameter greater than that of the radial bore 51 to prevent the pin 53 from escaping radially outwardly through the bore 51. These flanges 54 bear against the shoulder 34 of the collar 31 to retain them in place. Alternatively, the pins 53 could be fixed to the leaf springs 55.

In order to remove the detachable drive end 20, using the retaining structure 50 of FIGS. 8 and 9, a suitable tool may be inserted in the radial bores 51 to depress the pins 53 against the urging of the leaf springs 55 until the pins 53 clear the inner ends of the bores 51, whereupon the drive end 20 can be withdrawn. In the embodiment of FIGS. 10 and 11, no tool is needed. The extensions 56 have a length such as to project outwardly of the outer surface of the housing 12, so that they can be manually depressed with the user's fingers to disengage the pins 53. In this case, narrow notches 52 are formed in the front end of the housing 12 communicating with the bores 51 to permit passage of the pin extensions 56 when the drive end 20 is removed.

Referring to FIG. 12, there is shown another alternate form of retaining structure, designated 60, which utilizes the same pins 53 described above in connection with FIGS. 8 and 9. However, in this case the drive end mechanism includes a modified cylindrical collar 61 having a radially outwardly extending annular flange 62 at its rear end. Laterally extending ledges 63 join the outer surface of the collar 61 to the front surface of the flange 62. Seated on the ledges 63 are helical compression springs 64, which respectively resiliently bias brackets 65 outwardly. In particular, each bracket 65 has a lug 66 extending into the associated spring 64 and frictionally secured thereto. The lengths of the brackets 65 are such as to engage the inner ends of the pins 53 for holding them in the bores 51. Suitable tools can be used to depress the pins 53 and the brackets 65 against the urging of the springs 64 to release the drive end mechanism. A similar retaining structure, designated 60a, is shown in FIG. 13, the difference being that each bracket 65 is provided with an extension 67 projecting outwardly through a suitable opening 69 in the housing 12 and having a head 68 for manually depressing the bracket 66 with the user's fingers. Slots (not shown) in the front end of the housing 12 may communicate with the openings 69 to facilitate removal of the retaining structure 60a with the drive end 20, similar to the arrangement described above with respect to FIGS. 10 and 11. In both of the embodiments of FIGS. 12 and 13 the pins 53 could be connected to the brackets 65.

Another embodiment of retaining structure, designated 70 is shown in FIGS. 14 and 15, which utilizes the collar 61 of FIGS. 12 and 13. In this case, the housing structure 11 includes a rotatable ring 72 mounted on the end of the housing 12. The springs 64 bias pins 71 into engagement with the inner surface of the ring 72. The pins 71 seat in tapered notches 73 on the inner surface of the ring 70 in a locked position shown in FIG. 14 to hold the drive end 20 in place. To remove the drive end 20, the ring 70 is rotated in the

direction of the arrow in FIG 15, the notches 73 cammingly depressing the pins 71, so that they can ride up out of the notches to free the drive end 20.

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 obvious to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants' 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.