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Switch reduction in a cordless power toolSwitch reduction in a cordless power tool description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20050248320, Switch reduction in a cordless power tool. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/568,038, filed May 4, 2004, the teachings of which are incorporated herein by reference. FIELD [0002] The present disclosure relates to cordless power tools and, more particularly, to reduction of switches in a cordless power tool. BACKGROUND [0003] A wide variety of cordless power tools are available that may be utilized in different applications such as construction applications, fire and rescue applications, etc. Some examples of cordless power tools include, but are not limited to, cordless drills, cordless circular saws, cordless reciprocating saws, cordless sanders, cordless screwdrivers, and flashlights. Cordless power tools may utilize a rechargeable battery pack for providing power to operate the tool. The rechargeable battery pack may be readily removed from the cordless power tool and coupled to an external battery charger for charging purposes. [0004] The battery pack may include one or more battery cells. The battery pack may also include monitoring circuitry to monitor parameters such as cell voltage levels, discharge current, and charging current. The battery pack may also include switches such as a discharge switch which may be opened in response to the monitoring circuitry detecting some overload condition. Another control switch may be utilized in the cordless power tool to control a level of discharge current supplied to a load of the cordless power tool. For example, the control switch may be a speed control switch to control the speed of an element of the cordless power tool. This switch may be a relatively expensive switch requiring overload protection. Accordingly, there is a need in the art to eliminate the speed control switch yet still provide similar functionality. BRIEF SUMMARY OF THE INVENTION [0005] According to one aspect of the invention, there is provided a battery pack. The battery pack may include at least one battery cell, a discharge switch coupled to the at least one battery cell, and monitoring and control circuitry responsive to a position of a trigger of an associated cordless power tool to provide a control signal to the discharge switch, the discharge switch responsive to the control signal to control a discharge current provided to a load of the cordless power tool. [0006] According to another aspect of the invention, there is provided a cordless power tool. The cordless power tool may include a load, a trigger, and a battery pack. The battery pack may include at least one battery cell to provide power to the load. The battery pack may further include a discharge switch coupled to the at least one battery cell, and monitoring and control circuitry responsive to a position of the trigger to provide a control signal to the discharge switch. The discharge switch may be responsive to the control signal to control a discharge current provided to the load. [0007] According to yet another aspect of the invention there is provided a method. The method may include monitoring a position of a trigger of a cordless power tool, and controlling a state of a discharge switch of a battery pack in response to the position of the trigger to control a discharge current provided to a load of the cordless power tool. BRIEF DESCRIPTION OF THE DRAWINGS [0008] Features and advantages of embodiments of the claimed subject matter will become apparent as the following Detailed Description proceeds, and upon reference to the Drawings, where like numerals depict like parts, and in which: [0009] FIG. 1 is a perspective view of a cordless power tool; [0010] FIG. 2 is a diagram of a power supply system of the cordless power tool of FIG. 1; [0011] FIG. 3 is a diagram consistent with FIG. 2 where the load is a motor driving an element of the cordless power tool; [0012] FIG. 4 is another diagram a power supply system for the cordless power tool of FIG. 1; [0013] FIG. 5 is a diagram of an embodiment of the monitoring and control circuitry; and [0014] FIG. 6 is a flow chart of operations consistent with an embodiment. [0015] Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly. DETAILED DESCRIPTION [0016] FIG. 1 is a perspective view of a cordless power tool 100. The cordless power tool 100 is illustrated as a cordless drill and may be described as such in relation to embodiments herein. However, the cordless power tool 100 may be any type of cordless power tool including, but not limited to, a cordless circular saw, a cordless reciprocating saw, a cordless sander, a cordless screwdriver, and a flashlight. The cordless power tool may include a rechargeable battery pack 102 for providing power to operate the tool 100. The rechargeable battery pack 102 may be readily removed from the cordless power tool 100 and coupled to an external battery charger for charging purposes. The cordless power tool 100 may also include a trigger 104. For the drill, a user may depress and release the trigger 104 to control the speed of the chuck 142. For other tools such as a flashlight, a user may position a trigger to control a level of illumination from the flashlight. [0017] FIG. 2 is a diagram of a power supply system 200 of the cordless power tool of FIG. 1. The power supply system 200 may include the battery pack 102, a load 240, the trigger 104, and tool identification (ID) circuitry 230. As used in any embodiment herein, "circuitry" may comprise, for example, singly or in any combination, hardwired circuitry, programmable circuitry, state machine circuitry, and/or firmware that stores instructions executed by programmable circuitry. [0018] The battery pack 102 may include one or more battery cells 203 to provide power for the system 200. The battery cells 103 may be lithium ion cells in one embodiment. The battery pack 102 may provide power to the load 240 via the discharge switch 209. In one embodiment, the discharge switch may be a field effect transistor (FET). The battery pack 102 may also include monitoring and control circuitry 208. The monitoring and control circuitry 208 may measure one or more of battery pack current, temperature, and cell voltage levels for each battery cell. Continue reading about Switch reduction in a cordless power tool... Full patent description for Switch reduction in a cordless power tool Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Switch reduction in a cordless power tool patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Switch reduction in a cordless power tool or other areas of interest. ### Previous Patent Application: Battery failure discharge apparatus Next Patent Application: Fly wheel energy storage system Industry Class: Electricity: battery or capacitor charging or discharging ### FreshPatents.com Support Thank you for viewing the Switch reduction in a cordless power tool patent info. IP-related news and info Results in 0.12276 seconds Other interesting Feshpatents.com categories: Software: Finance , AI , Databases , Development , Document , Navigation , Error pbckp |
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