Patent Application
20140338504
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 geometry for securing an LED in 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. Windows in the clamshell housings may be provided for mounting the LEDs. The windows may be overmolded with a transparent or semitransparent material such as rubber or plastic to allow passage of light from the LEDs while protecting the internal components from water, dust and other foreign material.
Securely locating an LED in the clamshell housing has previously been accomplished by mounting the LED to a separate component such as a snap fit plastic insert or printed circuit board (PCB) before installing the LED and the separate component in the housing. These techniques have increased manufacturing costs by increasing the assembly steps and number of parts used to manufacture the motorized hand tool.
According to aspects of the present invention, the cost of a motorized hand tool, such as a cordless ratchet wrench, may be reduced through reduction of parts count and by eliminating the manufacturing steps involved with installing a light emitting diode (LED) in the clamshell housing. According to an embodiment of the present invention, geometry inside a plastic overmolded clamshell housing portion is configured to engage an LED and its conductors to protect the LED and securely locate the LED in the clamshell housing.
According to embodiments of the present invention, a motorized hand tool includes fingers molded in a clamshell housing to locate an LED by defining channels configured for receiving conductors extending from the LED. The conductors may be overmolded or enclosed in a shrink wrap material to provide a rigid sleeve around the each of conductors. Each conductor is mounted in a channel defined by fingers extending into the clamshell housing by friction fit between the rigid sleeve and the fingers. The LED is securely located in a window extending through the clamshell housing by trapping the encapsulated conductors between the fingers.
According to aspects of the present invention, an internal component such as a switch assembly is mounted in the clamshell housing over the fingers. The internal component covers the channels to contain the conductors of the LED in the channels. This avoids the use of snap fit components, additional fasteners or adhesives, which add cost to the manufacturing process.
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 motorized hand tool, such as, for example, the cordless ratchet tool shown in
The switch assembly 322 may be coupled to the motor assembly 320 and/or to a source of power such as one or more batteries (not shown). One or more LEDs 332 may be coupled to the power source via circuitry configured for controlling functions of the tool, for example. The one or more LEDs 332 are configured for viewing through the first clamshell housing portion 316 and/or the second clamshell housing portion 318. Portions of the circuitry coupled to the LEDs 332 may be included in the switch assembly 322 or may be located separately within the clamshell housing portions 316, 318, for example.
The clamshell housing includes one or more windows 324 arranged for locating a corresponding LED 322 to allow a user to view light emitted by the LED. According to an embodiment of the present invention, a window 324 in the second clamshell housing portion 318 is overmolded with a transparent or semitransparent material such as a semitransparent rubber or plastic, for example. Alternatively a separate window covering element may be installed over the window 324 by snap fit, glue or other fastening means. The window 324 is at least partially bounded by a window boss 326 extending inward from the second clamshell housing portion 318.
The clamshell housing portion 318 includes a set of fingers 328 and a set of channels 330 defined by spaces between the fingers 328. According to an aspect of the present invention, conductors extending from the LED 332 are each enclosed in a rigid sleeve 334. In one embodiment of the present invention, the rigid sleeve may be formed by overmolding the conductors extending from an LED before installing the overmolded conductors in the clamshell housing. In another embodiment, the rigid sleeve may be formed by shrink wrapping the conductors with a plastic heat shrink tubing, for example. The conductors and rigid sleeves 334 are installed in the set of channels 330 and retained by a friction fit between the fingers 328 and each of the rigid sleeves 334.
The LED 332 is inserted into a friction fit hole in the rubber overmolded portion of the window 324 which helps keep the LED 332 in place and cushions the LED 332 to protect it from drop or impact damage.
According to another aspect of the present invention, the switch subassembly 322 is installed over the channels 330 and captures each of the LED conductors and rigid sleeves 334 in their respective channel 330. Although embodiments of the present invention are described which include the use of a switch assembly 322 to capture each LED conductors and rigid sleeves 334 in their respective channel 330, it should be understood that alternative embodiments of the present invention may include the use of one or more alternative internal components of the motorized hand tool such as a motor, motor plate, gearbox, battery, for example, to capture the LED conductors and rigid sleeves in their respective channels.
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 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 (not shown) such as a steel wave washer or an O-ring 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 O-ring 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
In step 606, the process includes installing the LED in an overmolded window in the first portion of the clamshell housing. In step 608, the process includes capturing the set of conductors in the channel by locating a switch assembly over the set of channels. In step 610 the process includes aligning a second clamshell housing portion against the first clamshell housing portion and installing one or fasteners to couple the first clamshell housing portion to the second clamshell housing portion.
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.
