Patent Application
20140338503
The present invention relates to a motorized hand tool for applying torque to a work piece. More particularly, the present invention relates to a clamshell housing coupling to a head assembly of a motorized hand tool.
Power hand tools, such as motorized ratchet wrenches and drivers, are commonly used in automotive, industrial and household applications to install and remove threaded fasteners and to apply a torque and/or angular displacement to a work piece such as a threaded fastener, for example. Motorized hand tools, such as cordless power ratchets and drivers, generally include an electric motor contained in a clamshell housing along with other components such as switches, light emitting diodes (LEDs), and batteries, for example. The clamshell housing generally includes two or more housing portions fastened together by fasteners, such as screws or rivets.
The process of assembling a clamshell housing to a drive member, such as a ratchet head housing in a motorized hand tool, generally involves one or more large clamp nuts or a set of screws in addition to fasteners used to couple portions of the clamshell housing together, for example. The additional large clamp nuts and/or screws may create an unsightly appearance and may add bulk to portions of the tool, thereby impeding proper use of the tool in small spaces. The large clamp nuts may also loosen over time and allow the ratchet head to become loose from the clamshell housing.
According to embodiments of the present invention, a motorized hand tool, such as a cordless ratchet wrench, includes a clamshell housing that may be fastened to a drive member such as a ratchet head assembly without the use of additional fasteners such as large clamp nuts or additional screw sets, for example. One or more protrusions extending inwardly from the clamshell housing engage similarly shaped voids in the ratchet head assembly. The protrusions may include a radial flange, a T-shaped protrusion and/or one or more screw bosses. The protrusions tightly engage the ratchet head housing when the clamshell housing portions are fastened together. The rigid connection created between the clamshell housing and the ratchet head housing absorbs torque and helps prevent the tool from breaking apart when subject to drops or other impacts.
According to aspects of the present invention, the cost of a motorized hand tool may be reduced by reduction of parts count and eliminating the manufacturing steps involved with installing clamp nuts or screws dedicated to fastening the ratchet head assembly to the clamshell housing. The disclosed hand tool is aesthetically improved and has fewer external fasteners that could loosen and/or interfere with comfortable use of the tool.
For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments 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.
It should be understood that the comments included in the notes as well as the materials, dimensions and tolerances discussed therein are simply proposals such that one skilled in the art would be able to modify the proposals within the scope of the present invention.
While this invention is susceptible of embodiments in many different forms, there is shown in the drawings, and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present invention is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated.
Embodiments of the present invention may be implemented in a hand tool, such as the cordless ratchet tool shown in
A ratchet head and motor subassembly 400 according to an aspect of the present invention is described with reference to
The motor end plate 426 may be fastened to the electric motor 424 by fasteners such as rivets or screws through fastener holes 430, for example. According to an aspect of the present invention, the motor end plate 426 includes one or more outwardly protruding semi-annular flanges 428. The flanges 428 are configured to fit in a semi-annular slot 432 formed by an undercut behind a lip 434 around a periphery in the ratchet head housing 412. One or more discontinuities in the lip 434 create one or more apertures 436 that are sized to cooperatively receive each of the one or more flanges 428 of the motor end plate 426 during assembly of the motor end plate 426 to the ratchet head housing 412 and during disassembly of the motor end plate 426 from the ratchet head housing 412. The motor end plate 426 may also include one or more detent structures (not shown) configured to provide tactile indications of proper rotation displacement during assembly.
According to aspects of the present invention, the motor assembly 420 is coupled to the ratchet head housing 412 by pushing the flanges 428 of the motor end plate 426 through the apertures 436 in the lip 434 of the ratchet head housing 412 then rotating the motor assembly 420 relative to the ratchet head housing 412 until the flanges 428 of the motor end plate 426 are secured in the semi-annular slot 432 of the ratchet head housing 412. In one example, the flanges 428 and apertures 436 are sized so that the motor assembly 420 may be rotated 90 degrees in either direction to engage the semi-annular slots 432 of the ratchet head housing 412 during an assembly process or to disengage the semi-annular slots 432 of the ratchet head housing during a disassembly process. A compressible member such a steel wave washer or an O-ring (not shown) made from a compressible material such as rubber or other elastomer, for example, may be installed between the motor assembly 420 and the ratchet head housing 412 to absorb dimensional tolerances. The compressible member is compressed during assembly of the motor assembly 420 to the ratchet head housing 412 and provides pressure between the flange 428 and lip 434 that facilitates a tight fit and alignment of drive gears, for example. In an embodiment of the present invention, a rib protruding inwardly from one or more clamshell housing portions is shaped to substantially fill the one or more apertures 436 when the clam shell housing is assembled to the ratchet head and motor subassembly 400. Referring to
According to another embodiment of the present invention, one or more clamshell housing portions include one or more protrusions extending inwardly from the clamshell housing. The one or more protrusions tightly engage similarly shaped voids in the ratchet head assembly. Referring to
Referring to
As discussed above, the aspects of the present invention are described in terms of a cordless ratchet tool 100. as shown in
As used herein, the term “coupled” or “communicably coupled” can mean any physical, electrical, magnetic, or other connection, either direct or indirect, between two parties. The term “coupled” is not limited to a fixed direct coupling between two entities.
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. 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.
