Power Tools with Titanium Hammer Cases and Associated Flange Interfaces

RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/606,866 filed Mar. 5, 2012, the contents of which are hereby incorporated by reference as if recited in full herein.

FIELD OF THE INVENTION

This invention relates to power tools and is particularly suitable for hammer cases for impact wrenches.

BACKGROUND OF THE INVENTION

Various power tools, including corded electric, cordless electric and pneumatic tools are well-known. Examples of such tools include, but are not limited to, drills, drill drivers, impact wrenches, grease guns and the like. Many of these tools have a pistol style housing generally including a tool body defining a head portion with a handle depending therefrom, but other form factors can be used.

In the past, investment casting titanium hammer cases have been used for impact wrenches such as described in U.S. Pat. No. 7,222,680 and U.S. Patent Application Publication No. 2005/0161243, the contents of which are hereby incorporated by reference as if recited in full herein.

SUMMARY OF EMBODIMENTS OF THE INVENTION

Embodiments of the invention are directed to power tools. The power tools include: (a) an external titanium housing having a forward portion and a rearward portion and defining a cavity, wherein the titanium housing has a body of deep drawn titanium with at least a major portion thereof, including a rear section thereof, having a thin wall with a substantially constant thickness; (b) an interface flange residing in the titanium housing cavity; and (c) an external motor housing extending rearward of the external titanium housing and attached to the interface flange.

The interface flange can be bonded to the titanium housing.

The power tool can be an impact wrench and the titanium housing can be a hammer case.

In some embodiments, the interface flange can withstand a pull out force of least 1000 lbs. for two seconds.

The titanium housing can be a monolithic unitary body that is formed from deep drawn titanium to provide a rear portion that has a thin wall of substantially constant thickness.

The interface flange can have outwardly extending detents that can include a plurality of corner detents with small gap air spaces residing on opposing sides of each detent.

The interface flange can have opposing front and rear ends and an outerwall extending therebetween with at least one attachment feature on the outerwall residing between the front and rear ends. The titanium housing body can have at least one cooperating attachment feature residing on an internal surface thereof residing proximate a rear end portion of the titanium housing body. The interface flange and titanium housing body attachment features can tightly abut to define a mechanical joint.

The interface flange attachment feature can include at least one transversely extending recess and the titanium housing body attachment feature can include at least one inwardly extending projection.

Other embodiments are directed to hammer cases for a power tool impact wrench. The hammer case include a thin wall titanium shell tapering from a smaller forward section to a larger rearward section, with at least the rearward section having a wall with a substantially constant wall thickness.

The interface flange can include an outer perimeter profile that is curvilinear and defines a plurality of outwardly extending detents that provide an interference fit with the wall of the hammer case.

The interface flange detents can include a plurality of corner detents with small gap air spaces residing on opposing sides of each detent prior to bonding.

There can be six substantially equally spaced apart interface flange detents.

Optionally, in some embodiments, the detents can provide about a 0.002 inch interference fit and adjacent gap spaces of about 0.005 inches.

The interface flange can be bonded to the hammer case so that a rear surface of the flange is flush with a rear of the hammer case.

The interface flange can withstand a pull out force of least 1000 lbs. for two seconds, typically about 5000 lbs. for two seconds, without failure of the joint.

Other embodiments are directed to methods of assembling a power tool. The methods include: (a) providing a hammer case having a titanium shell body; and (b) press fitting an interface flange into a rear portion of the shell body of the hammer case.

The interface flange can have outwardly extending detents that are sized and configured to form an interference fit against an inner surface of the thin wall.

The method can also include, after the press fitting, welding, brazing, bonding, or otherwise permanently attaching the interface flange to the hammer case shell body so that the interface flange can withstand a pull out force of about 1000 pounds for at least two seconds without joint failure.

The titanium shell body can be a deep drawn titanium shell body with a rear portion having a thin wall.

The detents, where used, can include four corner detents that engage the inner surface of the thin wall of the shell body leaving small air gap spaces about a perimeter of a junction of the shell body and the flange. The method can include, after the press fitting, inserting an epoxy into the gap spaces and curing to secure the interface flange to the hammer case.

The interface flange can have an outer perimeter profile that is curvilinear and an inner perimeter profile that is circular.

The interface flange detents can include a plurality of corner detents and interior detents residing between each corner detent and the press-fitting step can be carried out so that there are small gap air spaces residing on opposing sides of each detent.

There can be six substantially equally spaced apart interface flange detents.

Optionally, the press fitting can be carried out to provide about a 0.002 inch interference fit using the detents and adjacent gap spaces of about 0.005 inches.

The press fitting can include pushing the interface flange into the shell body of the hammer case so that a rear surface of the flange is flush with a rear of the hammer case.

The titanium housing can be a monolithic unitary body that is formed from deep drawn titanium and the rear section has a substantially constant thickness thin wall.

Embodiments of the invention are directed to providing power tool cases that comprise deep drawn thin titanium cases that can reduce material and/or labor costs associated with investment castings while providing the desired strength and/or structural rigidity.

Embodiments of the invention are directed to a power tool with a deep drawn titanium hammer case attached to a flange using interference fit detents.

The foregoing and other objects and aspects of the present invention are explained in detail in the specification set forth below.

It is noted that aspects of the invention described with respect to one embodiment, may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. These and other objects and/or aspects of the present invention are explained in detail in the specification set forth below.