Electrical connection for battery charging apparatus or the like

Abstract: An electrical connection for a battery pack to a battery charger or the like consisting of a bracket including a substantially flat male plate (12) having a plurality of spaced headed projections and female electrical terminals (111) carried within a projecting housing (31) and a substantially flat female plate (11) having a plurality of keyholes (15) designed to facilitate receiving the projections and pairs of fixed (19) and movable male electrical terminals (115, 117) positioned within a recess (18) for engagement with the female electrical terminals.

Description: The invention relates to an electrical connection comprising a male plate and a female plate adapted to be releasably locked together in a connected condition, the female plate including a plurality of elongated slots, and a plurality of elongated electrical terminals, the electrical terminals being elongate in substantially the same direction as the slots, and the male plate including a plurality of spaced projections, each corresponding in location to a respective slot, and elongated electrical terminals corresponding in location to at least one respective electrical terminal on the female plate when the plates are releasably locked together. An electrical connection of the type mentioned above is disclosed by US-A-4,550,968. One disadvantage of the prior art device, is that it requires the male and female plates to have the same number of male terminals and corresponding female terminals, which must be located in line with each other so that the male terminals are received within the female terminals when the plates are coupled together. It may be desirable to have extra terminals in one of the plates, which may be used to drive an extra gauge or sensor, for example. However, if the extra terminal is a male terminal, then the other plate must have a corresponding female terminal to receive the male terminal. This can be a significant barrier to introducing new features requiring additional terminals. It is an object of the invention to improve the electrical connection of the type mentioned above. This object is obtained by the electrical connection as described in claim 1. One advantage of having at least one electrical terminal including a movable head, as recited in the characterizing part of claim 1, is that the movable head can be depressed, even in the absence of a corresponding terminal on the other plate, to establish a circuit connection. Thus, both plates are compatible, even though one may be provided with less circuits and function capability. Another advantage of the movable head, is that it can be spring biased to ensure maintenance of the electrical connection. The prior art, fixed terminals, on the other hand, may not maintain electrical contact if the terminal becomes loose or tilted, for example. Other characteristics of the electrical connection of the invention are described in the depending claims. In accordance with this invention, the electrical connection includes an electrical connector block provided on a female plate secured to an electrical device, such as a battery charger, although the female plate can be connected to a device, e.g., a camera or other portable device, which can be used to obtain and discharge power from a battery, rather than a device to charge a battery. A battery pack mounted on a male plate is releasably locked to the female plate and has electrical contacts in electrical communication with the battery pack to, for example, remove a charge from the battery charger to the battery pack or to establish a power connection to drive an electrical device. For purposes of discussions to follow, it will be assumed that the female plate is mounted on a battery charger, unless otherwise indicated, to recharge a battery pack carried on a male plate. Upon locking the male plate to the female plate, the electrical contacts on the male plate are brought into electrical engagement with a plurality of contact pins on the electrical connector block mounted on the female plate. The outermost pins on the electrical connector block are expandable banana plugs providing a positive (+) and a negative (-) circuit connection to allow powering of a device by a battery/power supply or recharging of a battery carried by the male plate and are received in cylindrical tubular contact elements on the male plate. The remaining pins on the female connector block all comprise a piston adapted to move linearly within a cylinder against the bias of a coil spring. The piston head may be enlarged for contact with a correspondingly located tubular pin or terminal carried by the male plate or may have a reduced diameter portion to conserve space, which extends upwardly to effect the requisite contact with a solid contact pin. Upon depression of the piston against the bias of the coil spring within its cylinder by one of the contact pins on the male plate, an electrical circuit can be established through the piston in sliding engagement with its cylinder. Each cylinder can be electrically connected to one or more charger circuits, which circuit can be used to energize a display, e.g., of a gauge to visually record the remaining voltage in the battery pack as it is charged or before recharging, if necessary. Another pin can be used to energize a circuit to enable a temperature responsive cut-off circuit in the charger to be activated so that the charger will not overheat when in use. Another one of the remaining contacts may, e.g., be used to establish an electrical circuit directly from the battery pack being recharged through its cylinder to sense whether the battery is resistor encoded or of a certain type compatible with the charger. The remaining pin can be used for a similar, albeit different communication between the battery pack and charger, e.g., to provide an analog output indicative of the remaining capacity in the battery, prior to recharging. The springs within each cylinder, upon depression, assure the maintenance of electrical contact between each piston and its corresponding contact pin on the male plate and allow depression of a contact on the female plate even in the absence of a corresponding pin on the male plate to establish a circuit at that location, so the female plate and its electrical connectors are compatible with a male plate provided with less circuits and function capability. US-A-4,218,107, assigned to the applicant of the present invention, discloses a battery pack connection which includes a female plate that is secured, for example, directly to a portable device such as a battery charger. The female plate is formed with a plurality of keyholes together with at least one male terminal with the keyholes and the terminal extending in the same direction but with the terminal being positioned within a recess spaced beneath the plane of the female plate. A male plate cooperates with the female plate and may form one side of a battery containing receptacle or pack. The male plate has a plurality of circular headed projections extending therefrom and at least one female terminal positioned within a housing that projects from the plane of the male plate. In use, the female plate is fixed and connected to the electrical charger device and if the male plate is part of the battery pack, the user positions the male plate against the female plate with initial alignment occurring between the recess and the housing and with said alignment preventing lateral shifting of the plate with respect to the slots of the keyholes. The user can then only move the male plate in the direction of the keyhole slots until the headed projections enter into circular openings of the keyholes. The male plate is then further moved to position the projections within the slots of the keyholes with said movement causing electrical connection between the male and female terminals, so that the battery pack carried by the male plate may be recharged. When the male plate has achieved its connected position, a tensioned flexible strip that is positioned behind one keyhole reverts to its normally biased position wherein it has a ledge which engages the head of the projection in said keyhole and prevents the two plates from moving from their connected position. For removing the plate, the user merely bends the flexible strip from its normal position which unlocks the engagement between the strip and the projection to thereby permit the male plate to be moved so as to position the headed projections within the circular openings of the keyholes. At this position, the terminals have been disconnected and the male plate can be removed from the female plate. BRIEF DESCRIPTION OF THE DRAWINGS Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein: FIGURE 1 is an exploded perspective view of a battery pack connector bracket adapted to be mounted on a battery charger including the electrical connection of the present invention; FIGURE 2 is a front view in elevation of the female plate of the battery pack connector bracket of FIGURE 1; FIGURE 3 is a top plan view of the female plate of FIGURE 2; FIGURE 4 is a longitudinal cross-sectional view through the female plate of FIGURE 2, illustrating in exploded detail one of the electrical connector pins employed in the electrical connector block mounted on the female plate; FIGURE 5 is a cross-sectional view of another one of the electrical connector pins employed in the electrical connector block mounted on the female plate; FIGURE 6 is a cross-sectional view of still another one of the electrical connector pins used in the electrical connector block mounted on the female plate; FIGURE 7 is a front view in elevation of the male plate of the battery pack connector bracket of FIGURE 1 with portions broken away for purposes of illustration; FIGURE 8 is a cross-sectional view taken substantially along the plane illustrated by line 8-8 of FIGURE 7; FIGURE 9 is a side view in elevation of the connected male and female plates of the battery pack connector bracket with portions of the plates removed and portions shown in section for purposes of illustrating certain components thereof; and FIGURE 10 is a view as seen along the plane indicated by line 10-10 of FIGURE 9, with portions removed and in section for purposes of illustration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, wherein like numerals indicate like elements through the several views, a battery pack connector bracket is generally indicated by the reference numeral 10 in FIGURE 1 and includes a female plate 11 and a male plate 12. The bracket 10 and the plates 11,12 and their operation are described in detail in US-A-4,810,204 issued on 7 March 1989, entitled Battery Pack Connection and assigned to the same assignee as the present invention. Such details are not part of the present invention, except for the electrical connections which may be used therein as described hereinafter, but the details of the battery pack connector brackets are incorporated herein by reference for understanding the background of the present invention. The plate 11 has a plurality of threaded apertures (not shown) on its backside corners by which it may be secured to an electrical device such as a battery recharging unit or the like (not shown) while the male plate 12 constitutes one side of a closed container which contains rechargable batteries. The container, if desired, may be secured to the male plate by fasteners extending into the peripheral edges of the plate. The female plate 11 is formed with a plurality of keyholes 15 cut in its front surface, each having an elongated ovoid or elliptical opening 16 and a narrow depending slot 17. The keyholes 15 include two upper slots and a centrally located lower slot disposed in a substantially triangular array. Formed between the two upper keyholes 15 is an open top recess 18 in which two male contact terminals 19 are secured. The terminals 19 are in the nature of banana plugs having expandable tips 101 and a threaded shank 103. As shown in FIGURES 1 and 4, they are positioned at the bottom wall 18a of the recess and secured thereto by passing through holes 105 in the bottom wall 18a of recess 18 formed therein into threaded engagement in tubular electrical contacts 109 provided in holes 107 in an electrical contact connector block 42 slid into engagement (as shown in FIGURE 4) with shoulders 44 (see FIGURE 3) from the rear of the female plate 11. The threaded shank 103 of terminals 19 hold the connector block 42 to the bottom wall 18a of the recess 18. The threaded shank portions 103 of terminals 19 threadedly engage metal inserts 109 inserted into holes 107 from the bottom thereof which enable wires to be secured thereto on the rear side of the female plate 11 to effect electrical connection to the terminals. By positioning the terminals 19 within the recess, they accordingly are located beneath the face of the front of the female plate and hence less subject to abuse during the substitution of one battery pack for another or when exposed. By providing a separable connector block 42, the wires can be connected first to the respective inserts 109 of block 42 as a subassembly, which then can be electrically attached through the insert 109 to the threadedly received shank portions 103 of terminals 19, after block 42 is inserted into female plate 11. This provides for ease of assembly and precludes the wires from floating about where they may be subject to disconnection. The electrical connector block 42 is slid onto the female plate 11 from the rear, riding over a cantilevered spring finger 48 which springs back up positioning a shoulder 50 behind the bottom edge 52 of the block 42 to hold it in place. The male plate 12 is formed with a plurality of projections 26, each of which has a large circular head 27 and an integral narrow leg portion 28. Extending beyond the face of the male plate is an integral housing 30 having the generally rectangular shape shown. An electrical contact terminal block 31 is provided in housing 30 with a plurality of holes 32 for receiving hollow electrical contact terminals 111 and solid terminals 113 (see FIGURE 10), as described in more detail hereinafter, at corresponding locations to the terminal contacts 19 on block 42 along with other types of terminals 115, 117 (as shown in detail in FIGURES 5 and 6 and discussed more fully hereinafter). The terminal block 31 is adapted to be slid into the male plate 12 from the rear of housing 30 (see FIGURE 1) with a U-shaped opening 33 surrounding a stationary post 34 molded integral with housing 30. The upper and lower edges of the block 31 are confined between upper and lower support shoulders 35,36 respectively, forming a groove. This arrangement permits pre-assembly of the contacts 111, 113 in the block 31 and their attachment to wire connections with the battery pack associated with the male plate 12 exterior to the male plate 12, and once the block 31 is slid into place on the male plate 12 and the plate connected in turn to the female plate, the male terminals 19 will be received in the hollow female contact terminals 111 in holes 32 and will self-align along with the other corresponding contact pin pairs 113,115 and 111,117 (see FIGURE 10) and make appropriate contact as the connector block 31 in the male plate 12 has restricted lateral movement about the stationary post 34 in a perpendicular direction between the support shoulders 35,36 as a small space 37 is provided between the side walls of the housing and the lateral edges of block 31. Slight back and forth movement is also contemplated, as a lock washer 38 received over post 34 on the rear of post 34 to prevent removal of block 31 from housing 30 is spaced rearwardly from an undercut edge of the block. This resultant movement in a horizontal plane removes the necessity of precisely molding the contact placements in both the male and female plates as the connection will be substantially self-aligning. A positive, thumb-actuated pivoted locking mechanism generally designated by the numeral 70 is adapted to be positioned over one of the headed projections 27 on the male plate 12 after it is seated in the slot portion 17 of a corresponding keyhole slot 15 in the female plate 11 to lock the male and female plates together after a new battery has been substituted with a male plate. The locking mechanism 70 is described in detail in US-A-4,810,204 mentioned before and forms no part of the present invention. Additionally, the locking mechanism can incorporate a safety latch 80 precluding inadvertent and accidental pivoting of the locking mechanism to an open position once the headed projection 27 is seated in the bottom of a keyhole slot 15. The latch 80 includes a knurled thumb-actuated slide 82 on the side wall of the female plate 11 which can be pushed up and down as also described in US-A-4,810,204 mentioned before to preclude accidental movement of locking mechanism 70 to an open position. Electrical connector block 42 is provided on a female plate 11 secured to an electrical device, such as a battery charger. A battery pack mounted on a male plate 12 is releasably locked to the female plate 11 and has electrical contacts in electrical communication with the battery pack to remove a charge from the battery charger to the battery pack. Upon locking the male plate 12 to the female plate 11, the contacts 111,113 on the male plate 12 are brought into electrical and mechanical engagement with contact pins 19, 115 and 117 on the electrical connector block 42 mounted on the female plate 11. The outermost pins 19 with enlargeable heads 101 on the electrical connector block 42 are expandable banana plugs providing a positive (+) and a negative (-) circuit connection to a source of power through the battery charger to recharge the batteries carried by the male plate and are received in conductive cylindrical tubular contact elements 111 in block 31. These hollow contact elements 111 have an enlarged head 119 and upright post 121 about which a wire lead to the battery pack being recharged can be attached. The remaining pins 115,117 on the female connector block 42 each include a piston 123 adapted to move linearly within an electrically conductable cylinder 125 against the bias of a coil spring 127. Each cylinder 125 has an annular, inwardly extending crimp 129 for abutment with the piston 123 to limit the extent of its upward movement in its cylinder 125 under urging of spring 127. The piston head 131 of contact pin 117 may be enlarged or mushroom-shaped for contact with a correspondingly located pin 111 carried by the male plate block 31, or a pin 115 may have a reduced diameter portion 133 to conserve space between pins extending upwardly from its piston 123 to effect electrical contact with correspondingly located solid pin 113. Upon contact and depression of the piston head 131 by tubular pin 111 against the bias of the coil spring 127 within the cylinder 125, an electrical circuit through the cylinder is established from pin 111, head 131 and piston 123 in contact with the cylinder wall. Suitable wire leads may be attached within a cup 135 provided on the bottom of cylinder 125 of pin 117, to tap the connection. Such a circuit can be used to energize a display, e.g., of a gauge to visually record the remaining voltage in the battery pack as it is charged or before recharging, if necessary. Another pin 117 of the enlarged headed piston type can be used to energize temperature responsive cut-off circuit in the charger so that the battery will not overheat when on charge. The reduced diameter piston head portion 133 of the remaining contacts 115 may, e.g., be used to establish an electrical circuit directly from the battery pack being recharged through solid pin 113 to its cylinder 125 from piston 123 to sense whether the battery is resistor encoded or of a certain type compatible with the charger. A cup 135 is also provided on the bottom of cylinder 125 of contact pin 115 to receive a wire lead which can be soldered to the cylinder 125. The remaining like pin 115 can be used for a similar, albeit different communication between the battery pack and charger or any like device. The springs 127 within each cylinder 125 allow depression of a contact 115,117 on the female plate 11 even in the absence of a corresponding pin 111 or 113 on the male plate 12 to establish a circuit at that location, so the female plate and its electrical connectors are compatible with a male plate provided with less circuits and function capability.

Claims: An electrical connection comprising a male plate (12) and a female plate (11) adapted to be releasably locked together in a connected condition, the female plate (11) including a plurality of elongated slots (15), and a plurality of elongated electrical terminals (19), the electrical terminals (19) being elongate in substantially the same direction as the slots (15), and the male plate (12) including a plurality of spaced projections (26), each corresponding in location to a respective slot (15), and elongated electrical terminals (111, 113) corresponding in location to at least one respective electrical terminal (19) on the female plate (11) when the plates (11, 12) are releasably locked together, characterized in that one electrical terminal (115, 117) provided on the female plate includes a movable head (131, 133) for forming an electrical connection and which is movable in substantially the direction of the elongated slots (15) and is depressed upon releasably locking the plates (11, 12) together. An electrical connection as defined in claim 1, further characterized in that the electrical terminals on the female plate (11) include a pair of terminals (19), each having a fixed head (101). An electrical connection as defined in claim 2, further characterized in that at least one of the fixed heads (101) is expandable laterally. An electrical connection as defined in any of the preceding claims, further characterized in that the at least one electrical terminal (115, 117) including the movable head (131, 133), includes an electrically conductive cylinder (125), an electrically conductive piston (123) movable within the cylinder and coupled to the head (131, 133), spring means (127) in the cylinder (125) for biasing the head (131, 133), and means for attachment to an electrical connector (135). An electrical connection as defined in any of the preceding claims, further characterized in that the movable head (131) is substantially mushroom-shaped. An electrical connection as defined in any of the preceding claims, further characterized in that the movable head (135) is defined by a reduced diameter portion. An electrical connection as defined in any of the preceding claims, further characterized in that the female plate (11) includes releasable locking means (70) for engaging at least one of the projections (26) in at least one of the slots (15) to lock the plates (11, 12) in connected condition by preventing relative movement between the plates (11, 12) in the direction of the slots (15) by maintaining the engagement of the locking means (70) with the projection (26) until the locking means (70) is released. An electrical connection as defined in any of the preceding claims, further characterized in that the electrical terminals (111, 113) on the male plate (12) either receive fixed heads (101) on the electrical terminals (19) on the female plate (11), or are engaged in contact with a movable head (131, 133) on another electrical terminal (115, 117) on the female plate (11) to depress the same in substantially the direction of the elongated slots (15) upon releasably locking the plates together to establish an electrical connection. An electrical connection as defined in any of the preceding claims, further characterized in that the female plate (11) includes more than three terminals (19, 115, 117) extending in substantially the direction of the elongated slots (15). An electrical connection as defined in any of the preceding claims, further characterized in that the terminals (19, 115, 117) on the female plate (11) are located within a recess (18) defined in the female plate (11).

Inventors: WILSON ANTON, WILSON, ANTON
Applicants: BAUER ANTON INC, ANTON/BAUER, INC.
Application year: 1987
Main classification: H01M2
IPC codes: H02J7, H01R24, H01M2, H01R13, H01M10