Battery operated power wrap tool

Abstract: A portable power tool for forming wire wrap type connec­ tions includes an electric motor, a torque transmitter and a casing for enclosing the electric motor and the torque transmitter. Re­ movably mounted to the casing is a battery pack (32). The battery pack mounts both rechargeable and non-rechargeable batteries so that the battery pack may not be recharged when non-rechargeable batteries are contained within the battery pack.

Description: The present invention relates to portable power tools and more specifically, the present invention relates to battery operated portable power tools with features of the preamble part of claim 1. The use of portable power tools to perform various tasks has become increasingly widespread. A specific example of such a portable power tool is a wire wrapping tool which is used to form a solderless connection between a wire and an electrical connector or terminal. In GB-A-2 072 438 the features of the preamble part of claim 1 are disclosed. This portable electrooptical diagnostic instrument comprises a casing to enclose the tool and a battery pack constructed and arranged to be removably mounted to the casing for providing electrical power to the tool. A battery pack has means for transporting electrical energy from either rechargeable or non-rechargeable batteries to the tool. To prevent possibility of the battery charger being used on the battery the charger has spring urged contact pin dimensioned so that it will contact a pole of the cell but will not contact an electrode of the battery. Therefore, the battery pack can be inserted into the charger even if non-recharageable batteries are used. If standard flashlight batteries are placed in the battery charger and are erroneously charged significant danger of damage to the batteries or to the user is present. Such to the batteries might include a leak of caustic acid from the battery casing. The possible damage to the user comes from the potential for explosion of standard batteries not designed for recharging the battery charger. In US-A-41 947 00 a portable battery-powered wire wrapping tool is described. This tool is capable of using standard batteries. The battery contact is effected via a conductive cap, a conductive housing retaining ring, and a specially configured contact strip. Batteries are disposed in a battery compartment whereby a cap at the lower end of the compartment is removeably threaded on a threaded portion of the compartment. The recharging of the batteries or the prohibition of recharging of non-rechargeable batteries is not disclosed by US-A-41 94 700. Therefore, it is an object of the invention to provide a portable power tool including a battery pack which enables utilization of both rechargable and non-rechargable batteries but prevents erroneously recharging of non-rechargeable batteries by use of the battery charger. This object is solved by the portable power tool with the features of the characterizing part of claim 1. Advantageous embodiments of the invention are disclosed by the subclaims. A portable power tool of the type used for solderless electrical connections formed by wrapping wire around a post or a terminal includes an electric motor and torque transmission means to transfer the torque developed by the electric motor to the work piece. The electric motor and the torque transmission means are enclosed in a casing. Removably mounted to the casing is a battery pack which serves as a handle for the portable power tool. The battery pack is designed to contain either rechargeable or non-rechargeable batteries. Further included within the battery pack is a spring mounting arrangement which, in addition to positioning the batteries within the battery pack, also serves to transmit electrical energy to the electric motor contained within the casing of the portable power tool. The shape of the interior of the battery pack positions the rechargeable batteries so that the battery pack with a rechargeable battery contained therein may be inserted in a battery charger. If the battery pack happens to contain non-rechargeable batteries, the shape of the interior of the battery pack will position the batteries so that the battery pack with the non-rechargeable batteries contained therein cannot be inserted into a battery charger. BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the device of the present invention may be had by reference to the drawings wherein: Figure 1 is a front elevational view of the portable power tool of the present invention; Figure 2 is a front elevational view of the power tool shown in Figure 1 with a side cover removed; Figure 3 is a view taken along line III-III in Figure 2; Figure 4 is a top view of the battery pack; Figure 5 is a view taken along line V-V of Figure 3; Figure 6 is a view taken along line VI-VI of Figure 2; and Figure 7 is an elevational view of the battery charger in relation to a partial sectional view of the battery pack. DETAILED DESCRIPTION OF THE EMBODIMENTS As shown in Figures 1 and 2 a portable power tool 10 typically of the type used to form wire wrap connections around electrical connectors or terminals (not shown) is powered by an electric motor 12. Electric motor 12 in portable power tool 10 provides torque to the collar and bit retaining section 14 at the operative end 16 of wire wrapping tool 10. In order to provide proper speeds and torques for wrapping wire the power from electric motor 12 is passed through a power transmission section 18 before reaching those parts of tool 10 which actually wrap wire around a connector or terminal. Enclosing both motor 12 and power transmission section 18 of portable tool 10 is a casing 20. Electrical connections 22 and 24 from electric motor 12 are mounted at the bottom 26 of casing 20 in opening 28 just behind trigger 30 which acts as an on and off switch for wire wrapping tool 10. Mounted within opening 28 is a battery pack 32. Battery pack 32 is mounted within opening 28 by two ear members 34 and 36 which fit into compatible slots 38 and 40 within opening 28 at bottom 26 of power tool 10. When engaged in opening 28, battery pack 32 has two electrical connections 42 and 44 which are placed into physical contact with the two compatible electrical connections 22 and 24 in bottom 26 of a portable power tool 10. As best shown in Figure 2 the battery pack 32 is sized so as to mount both standard "C" size batteries 46 and a "sub-C" size rechargeable battery 48 (shown in phantom). Commonly available "C" size batteries 46 are generally not rechargeable. Those which are rechargeable will not provide sufficient electrical power in a recharged state to properly operate the device. If a recharger 50 such as the one shown in Figure 7 is used with standard "C" size batteries 46 of either the rechargeable or non-chargeable variety, a leak may develop in the battery or the battery itself may explode. Both situations are potentially hazardous for the user of portable power tool 10. Such is not the case with rechargeable batteries as their internal design permits recharging. As "sub-C" battery 48 is somewhat smaller than the combination of two "C" size batteries 46, provision must be made for a accommodating both sizes of batteries within battery pack 32. This accommodation is accomplished in part by the use of two O-rings 52 which are slipped around the outside 49 of "sub-C" size battery 48. As best seen in Figures 2 and 5, at top 54 of battery pack 32 is a helical spring 56. Helical spring 56 is sized so that when two standard "C" batteries 46 are used, helical spring 56 will engage top portion 58 of the uppermost battery or top 47 of the rechargeable battery and provide a complete electrical path between the uppermost or positive battery terminal 60 and one of the electrical connections 44 in battery pack 32 which engage electrical connections 22 and 24 to motor 12 within casing 20. The other electrical connection is a spring strap 62 which is mounted within battery pack 32 to engage the bottom of either the pair of standard "C" cells 64 or the bottom of rechargeable battery 66. Spring strap 62 travels up side 68 of battery pack 32 to the other electrical terminal 42 in top 54 of battery pack 32. Because helical spring 56 is expandable, either "sub-C" type battery 48 or the pair of "C" type batteries 46 may be used in battery pack 32. As best shown in Figures 3, 4 and 6 the battery pack 32 itself is constructed in two halves 70 and 72. This enables either the pair of standard "C" size cells 46 or the "sub-C" cell 48 to be easily removed and replaced should such be required. As best shown in Figures 4, 5 and 6 the two halves of the battery pack 70 and 72 are connected by latches 74 and 76 at top 54 and at bottom 78, respectively. These latches 74 and 76 enable the user to separate halves 70 and 72 of battery pack 32 by merely inserting a small tool under top latch 74 and causing battery pack halves 70 and 72 to separate. This ease of operation eliminates the combersome task of removing a screw or a nut to gain access to the batteries. As best shown in Figure 3, a tongue and groove joint 96 is used on side 68 of battery pack 32 to position halves 70 and 72 one with respect to the other. Operation of the Device As can be best shown by reference to Figures 1 and 2 battery operated portable wire wrapping device 10 is used by inserting battery pack 32 in opening 28 in casing 20 of portable power tool 10. Battery pack 32 is then twisted until it locks in position. This twisting motion not only causes ears 34 and 36 to engage slots 38 and 40, but also causes electrical connections 42 and 44 at top 54 of battery pack 32 to mate with electrical connections 22 and 24 mounted in casing 20 of portable power tool 10. Beginning at the bottom of the battery or the negative terminal, an electrical current path is provided from either the negative terminal 80 of the "C" size battery or the negative terminal 82 of the "sub-C" rechargeable battery through spring strap 62 which travels up along side 68 of battery pack 32 through terminal 42 at top 54 of the battery pack 32 to terminal 22 in casing 20 of portable power tool 10 and thence to electric motor 12. The electric circuit is completed by electrical energy traveling through leads 84 and 86 exiting electric motor 12 and thence through connectors 88 and 90 formed within casing 20 of portable power tool 10 and on to the positive end 60 of either the rechargeable or non-rechargeable battery through helical spring 56 which is positioned on top 54 of battery pack 32. Should the operator desire to reverse the direction of rotation of the power tool 10 he simply removes battery pack 32 from casing 20 and rotates it 180°. This reversal of battery pack 32 will reverse the electrical polarity seen by electric motor 12, consequently, electric motor 12 will turn in an opposite direction. When it is desired to recharge the batteries within battery pack 32, battery pack 32 is removed from power tool casing 20 by twisting battery pack 32 with respect to casing 20. This causes ears 34 and 36 to exit slots 38 and 40. As shown in Figure 7 battery pack 32 is then placed in a battery charger 50 where a preselected current is applied to the batteries to restore their electrical potential. If the non-rechargeable batteries or the standard "C" size cells 46 are used in battery pack 32, the end of battery cells 46 will be approximately flush with the end of battery pack 32. This position of standard "C" size cells 46 within battery pack 32 will not permit battery pack 32 to be positioned within battery charger 92. This is because probe 94 on battery charger 50 must be inserted into the interior of battery pack 32 through aperture 92 (Figure 4) for battery pack 32 to be inserted in charger 92. With two standard "C" size cells 46 in battery pack 32, battery pack 32 itself will not be mountable within charger 50 hence battery pack 32 with non-rechargeable cells 46 therein can not be recharged. It is only when battery pack 32 contains a rechargeable cell 48 therein that probe 94 will enter the interior of battery pack 32 through aperture 92 thus allowing battery pack 32 to be placed in battery charger 50 and rechargeable battery 48 recharged. When it is desired to use regenerated battery pack 32 with portable power tool 10, battery pack 32 is removed from battery charger 50 and reinserted into casing 20 of portable power tool 10. Casing 20 and/or the housing surrounding the batteries in battery pack 32 may be formed of a strong, impact resistant insulating material. Particularly, a rubber or plastic based compound is exemplary of what may be used. Helical spring 56 or spring strap 62 in battery pack 32 may be any type of electrically conductive resilient and corrosion resistant material. Specifically, plated steel and aluminum are examples of two metals which may be used. There is now provided by the portable power tool 10 of the present invention, a portable power tool 10 which may be run on either rechargeable or non-rechargeable batteries. The positioning of the batteries within battery pack 32 prevents the operator from inadvertently creating a dangerous situation by inserting non-rechargeable batteries into a battery charger. While the present invention has been described in accordance with the preferred embodiment of a wire wrapping tool, it is to be understood that the invention has applicability to other portable power tools

Claims: A portable power tool (10) and a charger (50) for recharging batteries for said power tool, said power tool comprising a casing (20), an electric motor (12) and means (18) to transmit torque from said electric motor both enclosed in said casing (20), and a battery pack (32) as a receptacle for at least one battery (46, 48) removably mountable to said casing (20) for providing electrical power to said tool (10), said battery pack (32) having means (42, 44, 56, 62) for transmitting electrical energy from either rechargeable or non-rechargeable batteries (46, 48) of different lengths to said tool (10), and means (34,36,56,62) for mounting both recharageable and non-recharageable batteries including a spring mounting means (56) to position either kind of battery (46,48), characterized in that said charger (50) comprises a probe (94) for insertion into the interior of said battery pack (32) to prevent said battery pack from being placed in said charger (50) when said battery pack contains non-rechargeable batteries (46). The portable power tool (10) as defined in claim 1 characterized in that means are provided for rotating said battery pack (32) with respect to said casing (20), whereby the direction of rotation of the electric motor (12) is reversed. The portable power tool (10) as defined in claim 1, characterized in that said means (35,36,56,62) for mounting both rechargable and non-rechargeable batteries includes a housing (54,70,72,78; 74,76,96). Portable power tool as defined in claim 3, characterized in that said housing (54,70,72,78;74,76,96) is formed in two halves (54,70,72,78) and further includes means (74,76,96) for holding said halves together. The portable power tool as defined in claim 4, characterized in that said halves (54,70,72,78) are held together by latches (74,76). The portable power tool (10) as defined in one of the former claims, characterized in that said spring mounting means (56,62) serve as conducting paths for electrical current.

Inventors: KILMER PAUL ROBERT, KILMER, PAUL ROBERT
Applicants: COOPER IND INC, COOPER INDUSTRIES INC.
Application year: 1987
Main classification: H01R43
IPC codes: H01R43