GB2124839A - Improvements in or relating to a battery charger for rechargeable batteries - Google Patents

Abstract

A battery charger includes a casing (4), (Fig. 1), made of plastics material and having a battery terminal- engaging contact means (16) in the form of a moveable plate 42 carrying a contact and movable into a housing 12 against spring bias 17. A moulded receptacle 8 defines two tiers 22 (24) each of three channels (22a to c), (24a to c), the (a) (b) and (c) channels being respectively dimensioned to each receive two D-, C-, and AA- size cells respectively. Fixed positive contacts 34, 52, 56 are aligned with the central axes of corresponding channels. Each tier 22 (24) has a corresponding movable plate 42 carrying the negative contacts formed by protrusions on an associated leaf spring 17; in a modification the positive contacts are of similar form to the negative contacts. The receptacle 8 may be arranged also to receive a PP3 type 9 volt battery for which contacts may be located between the top two positive contacts 52. <IMAGE>

Description

SPECIFICATION Improvements in or relating to a battery charger for rechargeable batteries This invention relates two a battery charger for rechargeable batteries and moreespeciallytoa battery chargerfor nickel cadmium rechargeable dry cell batteries.

According to the invention there is provided a battery chargerfor rechargeable batteries including a casing for accommodating one or more rechargeable batteries aligned along an axis of the casing, the casing having one or more spaced-apart contact means, at least one contact means including a housing in which is mounted a resilient member to which is attached a movable plate, the movable plate coacting with the resilient member to move a portion ofthe movable plate into the housing on the application of axial pressure to the moveable plate.

An embodiment ofthe invention will now be described by way of example and with reference to the accompanying partially diagrammatic drawings in which: Figure 1, is a plan view of a battery chargerfor rechargeable batteries, with a lid ofthe battery charger removed; Figure 2, is a cross-sectional side elevation of the battery chargertaken along the line ll-ll of Figure 1 with the lid shown in the closed position and electrical circuitry omitted, and Figure3, is a cross-sectional end elevation of the battery charger taken along the line Ill-Ill of Figure 2.

With reference to Figures 1 to 3 of the accompany ingdrawingsthe battery charger 2 for rechargeable batteries especially ofthe nickel cadmium type, includes a casing 4for accommodating the nickel cadmium batteries, a lid 6 forthecasing, which lid may be transparent, and a mains lead (not shown) which extends from the casing 4.The casing 4 is of a plastics material and includes a separate central receptacle 8 mouldedin a single piece, accommodating one or more nickel cadmium batteries and has at one end a cover 10 enclosing electrical circuitry for effecting recharging ofthe batteries, and, atthe other end, a pair of contact means 16 including a housing 12.

The central receptacle a is attached to a rectangular base 18 ofthe casing 4whose major axis extends along the length thereof, bytwo opposed perpendicularly extending side plates 20 which each extend beyond a base portion ofthe central receptacle. The central receptacle 8 is moulded as two identical tiers 22,24, the tiers 22,24 are aligned side by side and in parallel with the major axis of the base of the casing.

Each tier 22,24 has three channels 22a, 22b, 22c, 24a, 24b, 24c each having a central major axis extending parallel to the major axis of the base 18 ofthe casing 4 in a plane extending perpendicularlytothe base 18.

The three channels 22a-c, 24a-c are part cylindrical in shape and are open attheir uppermost surfaces and baseswiththeexception of the channel 22c,24catthe base of each tier 22,24 adjacent the base 18 ofthe casing 4. The width of the channels 22a-c, 24a-c increases progressively from one channel of the tier 22, 24to the next with the channel 22c, 24c at the base ofthe tier 22, 24 having the smallest width. The channels 22a-c, 24a-c are dimensioned to accommodate co-axially in each channel of a tier 22, two nickel cadmium batteries end to end for example as shown in chain dotted outline in Figure 2 in channel 22c.

The channel 22a, 24a atthetop of a tier 22,24 is dimensioned to accommodate two nickel cadmium batteries such as D size batteries each having a diameter of approximately 34mm, thechannel 22b, 24bisdimensionedto accommodatetwo nickel cadmium batteries such as C size batteries having a diameterofapproximately26mm and the channel 22c, 24c atthe base of the tier 22,24 is dimensioned to accommodatetwo nickel cadmium batteries such as AA size batteries having a diameter of approximately 15mm. The two tiers 22,24 are fused together by a central part cylindrical portion 26 which extends longitudinally and in parallel with the major axis of the base 18 ofthe casing 4.Similar part cylindrical portions 28 fuse each tiertothetwo opposed side plates 20. Thewalls ofthe channel 22a, 24a at the top of each tier extend longitudinallyfrom one end of each tierto form a longitudinal projection 30 which extends transversely to the major axis ofthe casing. Beneath this projection is a portion ofthe central receptacle 8 which extends transversely of the major axis ofthe base ofthe casing to form a wall 32 at the end of each ofthe remaining channels of each of the tiers 22,24.

Attached to the wall 32 are a pair of contact terminals34 each pair of contactterminals 34 include a rivetwhich is mated, through a bore in the wall 32 with a further rivet portion which projects into the central receptacle. Each pair of contact terminals 34 are spaced-apart and aligned with the respective central major axis of the associated channel 22c, 24c at the base of each tier 22,24.

The pair of contact means 16 atone end of the central receptacle 8, includes a housing 12 having a rectangularwall 36 positioned transversely of the major axis of the base 18 ofthe casing and attached to a rear edge ofthe base ofthe casing so as to extend perpedicularlythere from. Projecting away from the wall 36 towards the central receptacle 8 and attached to the wall 36 is another portion of the housing 12 having a rectangular cross member 38 which extends transversely ofthe major axis ofthe base 18 of the casing 4 and which joins two opposed side plates attached to the base of the casing 18, to form a partially enclosed space adjacent to one end of the central receptacle. Into the partially enclosed spaced is fixed a dividing plate 40 which extends perpendicular lyto the base 18 of the casing and to the cross member 38 of the housing 12. The dividing plate 40 is aligned along the major axis of the base 18 ofthe casing 4to divide the partially enclosed space into two substan tially equal spaces.

A leaf spring 17 made oftempered steel and electroplated is positioned within each space. Each The drawing(s) originally filed were informal and the print here reproduced is taken from a later filed formal copy.

leaf spring 17 includes two opposed limbs joined by a return bend. One ofthe limbs of each leaf spring 17 is bentto form three protrusions which are aligned along a major axis ofthe limbs and which are spaced apartso asto align with the central major axis of each ofthe channels 22a-c, 24a-c in a tier 22,24. The limb of each leaf spring 17 which has the three protrusions on it is fitted into a perpendicularly extending groove in one face of a pair of rectangular plates 42 so that the protrusions project toward the channels 22a-c 24a-c of the central receptacle 8th rough apertures in each groove, and so that the other limb of each leaf spring 17 extends towards and comes into contact with an innerface ofthe wall 36 ofthe housing 12 when each ofthe pair of rectangular plates 42 is positioned flush with the housing 12. The rectangular plates 42 are prevented from emerging from the housing 12 by abutting against the side plates 20 ofthe central receptacle 8. In addition the plates 42 include projections (not shown) on their innerfaces which abut against the inner face ofthe wall 36 ofthe housing 12 to prevent over-compression of the spring 17 when the plates 42 are moved into the housing 12.

Attheotherend of the central receptacle is the cover 10 which accommodates the electrical circuitry (not shown). The cover 10 includes a rectangularwall 44 which is positioned transversely to the major axis of the base 18 of the casing 4 and is attached to a front edge of the base of the casing so as to extend perpedicularlyfrom the front edge of the base 18 of the casing. Projecting away from the wall towards the central receptacle and attached to the wall 44 is a portion of the cover having a cross member 46 which extends transversely ofthe major axis of the base 18 of the casing and which joins two opposed side plates attached to the base ofthe casing to form a partially enclosed space.Within the partially enclosed space and attached to the base ofthe casing are shaped projections which form a housing 48 for a transformer.

Positioned transversely with respect to the major axis ofthe base 18 ofthe casing and with respect to an end ofthecover 10 remote from the wall 44and adjacent to the central receptacle is a plate 50. The plate 50 abuts against the central receptacle 8 to form a closureforthe cover 10 and to form a closure for one end of each ofthechannels 22a, 24a atthetop of each tier 22,24. The plate 50 is rectangular in shape having a top portion which projects away from the central receptacle 8 and abuts againstthe cross member 46 of the cover 10.

The plate 50 has attached thereto a pair of contact terminals 52, each contact terminal 52 is aligned with the central major axis of each one ofthe channels 22a, 24a atthe top of each tier, and is aligned perpendicularlywith the pair of contactterminals 34 attached to the central receptacle 8. Each contact terminal 52 includes a rivet, which is mated,through a bore in the plate 50, with a further rivet portion which projects away from the plate 50 towards the channels 22a, 24a.

Atop portion ofthe plate 50 has two aligned and spaced apart apertures positioned transverse to the major axis of the base 18 ofthe casing and aligned perpendicularly with respect to the channels of each tier. Each aperture accommodates a light emitting diode 54which projects through the top portion away from the casing.

Attached to a base edge of the plate 50 which abuts against the central receptacle are a pair of contact terminals 56, each contact terminal 56 is aligned with the central major axis of each one ofthe channels 22b, 24b of each tier 22,24. Each one of the pair of contact terminals 56 includes a strip portion one end of which is attached to an inner face of the plate 50, so that a major axis ofthe strip projects into the central receptacle 8, the strip is bent th rough 90 at a free end and the free end is attached to an inner face of the plate 32 ofthe central receptaclethrough an aperture in the piate 32.

The pairs of contactterminals 34,52 and 56 attached to the central receptacle 8 and the plate 50, and the contact means 16 are aligned longitudinally with respect to the central major axis of each channel 22a-c, 24a-c in each tier 22,24, and are in register with respect to each other.

On assemblytheelectrical circuitry(notshown) is positioned in the partially enclosed space within the cover 10 at one end ofthe central receptacle. The electrical circuitry includes a transformer which is placed in the housing 48 within the cover 10. The transformer is connected in parallel to a rectifier system and to the mains lead (not shown) which extends through an aperture in the front wall 44 ofthe cover 10. The rectifier system is tapped on one polarity byfour resistors connected in parallel.Two of the resistors are connected in series with each of the pair of contactterminals 34, projecting into each one of the channels 22c, 24c at the base of each tier 22,24 and the othertwo resistors are connected in series to the pairs of contact terminals 52,56 projecting into each one ofthe remaining channels 22a-b, 24a-b of each tier 22, 24 these latter pairs of contact terminals 52,56 being electrically commoned. The other polarity of the rectifier system is connected in series to the limbs of the leaf springs 17 which abuts against the rearwall 36 ofthe housing 12 and each of these limbs is electrically commoned. In addition each of the light emitting diodes 54 is connected in parallel with the four rnsistors.

The lid 6 is then hinged to the side walls adjacent the rearwall 36 ofthe casing.The lid extends over the central receptacle 8 to abutagainstthe plate 50.

In operation two nickel cadmium batteries 100,200 (shown in chain dotted outline in Figure 2) are placed end to end in series in for example the channel 22c.

One end 101, of positive polarity, of the battery 100 abuts against one of the pair of contact terminals 34.

The other end 102 of negative polarity abuts against one end 201 of positive polarity of the battery 200 and the other end 202 of negative polarity abuts against Nthe protrusion alignedwith the central major axis of the channel 22c in one limb of the leaf spring 17. The effect ofthe end 202 of the battery 200 is to causethe plate 42 to pivot so moving a portion of the plate 42 adjacent the base of the housing 12 into the housing 12 by the battery 200 compressing the limbs of the leaf spring t7 together and towards the rearwall 36 of the casing.

With the batteries 100 and 200 positioned in the channel 22ctwo more nickel cadmium batteries (not shown) may then be placed end to end in series in the channel 22a. One end of positive polarity of one ofthe batteries abuts against one of the pair of contact terminals 52, attached to the plate 50. The other end of negative polarity abuts against one end of positive polarity ofthe other battery and the other end of negative polarity ofthe other battery abuts against the protrusion aligned with the central major axis of the channel 22a in the same limb ofthe same leaf spring 17 which causes the plate 42 to pivot so moving a portion of the plate adjacentto the top of the housing 12 into the housing 12 by the action of the batteries compressing the limbs of the leaf spring 17 together and towards the rear wall 36 of the casing.

The plate 42 thereby is perpendicularly positioned within the housing 12.

Asimilararrangement of nickel cadmium batteries may be placed in the other tier 24 or alternatively two nickel cadmium batteries may be placed end to end in series in the channel 24b.

When all the batteries which require recharging have been placed into the central receptacle 8 the lid 6 is closed overthecentral receptacle and the mains lead extending from the battery charger is connected to a supply to close the electrical circuit and cause the light emitting diodes54to emit light The light emitting diodes 54 emitting light indicate which diameter size of battery is being recharged. Energisation ofthe electrical circuitry ofthe battery charger is effected for an appropriate period of time for the batteries recharging,the mains lead is then disconnected from the supply and the recharged batteries removed from the central receptacle a ofthe battery charger 2.

In a modification, (not shown in the drawings) the central receptacle 8 has an additional moulding in the form of a tray positioned atthe end ofthetwo tiers 22, 24 adjacent the cover 10 for the electrical circuitry and between the channels 22a, 24a atthetop of each tier 22,24. The tray extends transversely into each of the channels 22a, 24a and extends longitudinallyfor a distance along the central major axis of each channel 22a, 24a. The tray accommodates a rectangular rechargeable batteryfor example a PP3 battery having a voltage of 9V. The battery is connected to a pair of central terminals (not shown) attached to the plate 50 between the pair of contact terminals 52. In orderto recharge such a battery additional resistors are connected into the circuit.In addition a further light emitting diode 54 is attached to the plate 50.

Although in the preceding description the contact means 16 have been positioned at one end ofthe central receptacle 8 similar contact means 16 may be usedtoreplacethecontactterminals34,52, 56 adjacentthe cover 10.

In addition although in the preceding description the contact means 16 has included a leaf spring 17 the leaf spring 17 may be replaced by a coiled spring which bears againstthe innerface ofthe plate 42 and the rearwall 36 of the casing. Contact terminals may then be attached to the face of the plate 42 remote from the rear wall 36 with the contact terminals aligned with each of the central major axes of each of the channels 22a-c, 24a-c in a tier 22,24 and connected in series to the rectifier system.

Also the leaf springs 17 and their associated plates 42 may be positioned transverse to the major axis of the base 18 of the casing to extend away from the side plates so that a column ofthree leafsprings 17 each having two protrusions on one limb is used as part of the contact means 16 at one end ofthe central receptacle. Also an additional leaf spring 17 may be providedforthe modification including a PP3 battery.

In addition although in preceding paragraphs one particular arrangement of nickel cadmium batteries has been described other arrangements of nickel cadmium batteries or other rechargeable batteries are possible so long as the physical arrangement of the batteries or combination of two such batteries together with the PP3 battery is such that a closed circuit is effected when the battery charger is connected to the supply.

Further although in preceding paragraphs the plate 50 has been described as having connected thereto two spaced apart pairs of contact terminals 52,56 for the channels 22a, 24a the plate 50 may also have connectedtheretothe pair of contactterminals 34.

This arrangement thus provides for all the pairs of contactterminals 34,52,56 including those for the PP3 battery to be connected onto the plate 50 before the plate 50 is assembled into the casing 4. In addition this arrangement of the plate 50 also permits the removal from the moulding of the central receptacle 8 of the wall 32 and the projection 30.

Also as an alternative the light emitting diodes 54 may be arranged to indicate which of the tiers 22,24 is being used in charging at leasttwo nickel cadmium batteries.

Furtherthe rearwall 36 ofthe casing may be formed as part of the housing 12.

Claims (10)

1. A battery chargerfor rechargeable batteries including a casing for accommodating one or more rechargeable batteries aligned along an axis ofthe casing, the casing having one or more spaced apart contact means, at least one contact means include a housing in which is mounted a resilient member to which is attached a moveable plate, the movable plate co-acting with the resilient member to move a portion ofthe moveable plate into the housing on the application of axial pressuretothe moveable plate.

2. A battery charger as claimed in claim 1, in which a pair of housings are used each housing having a resilient member mounted therein.

3. A battery charger as claimed in claim 1 orclaim 2 wherein the resilient member is a leaf spring, having two opposed limbs which are joined together buy a return bend.

4. A battery charger as claimed in claim 3, wherein one of the limbs of the leaf spring includes protrusions which projectthroughthe moveable plate and act as specific contact areas.

5. A battery charger as claimed in claim 4, wherein three protrusions are included on one of the limbs ofthe leaf spring.

6. A battery charger as claimed in any preceding claim wherein the casing includes a portion which is shaped as one or more tiers, which are aligned side by side and in parallel with the axes ofthe casing.

7. A battery charger as claimed in claim 6, wherein each tier includes one or more channels each having a central major axis extending parallel to the axis of the casing in a plane extending perpendicularly ofthe casing.

8. A battery charger as claimed in claim 7, wherein each channel is dimensioned to accommo dateatleasttwo rechargeable batteries aligning co-axially in each channel.

9. A battery charger as claimed in claim 8, wherein each channel in each tier is dimensioned such thatthe dimensions of one channel differwith respectto another channel ofthe same tier.

10. A battery charger arranged and adapted to operate substantially as herein before described with reference to the accompanying drawings.