Battery pack retaining latch for cordless device

A battery retention latch (350) comprises a retaining member (354), a release button (356) and a cam element (362). A biasing member 358 maintains the retention catch in a normally engaged position. The cam element (362) retains a battery pack (26) in a cordless device (352) regardless of the annular orientation of the battery pack (26) about a casing axis. A holding device (382, 394) maintains the battery (26) in the cavity (34) against a spring ejecting force such that the battery (26) partially extends from the device (352) enabling the battery (26) to be removed from the device (352).

FIELD OF THE INVENTION 
The invention relates to cordless (i.e. battery operated) devices such as 
portable electronic devices, toys, power tools or kitchen appliances. More 
particularly, the present invention relates to a battery pack latching 
ring to retain the pack in the device. 
BACKGROUND OF THE INVENTION 
For the consumer market, most cordless devices have a battery pack made 
integrally in the device housing because of reduced cost, increased user 
convenience and sturdiness. However, because of the desire to provide 
consumer devices with detachable packs, simplifying the recycling of the 
packs, and the desire to provide a family of cordless devices using an 
interchangeable pack and a single charger, there is a desire to use such a 
battery pack. Also, it is desirable to retain the battery pack in the 
device such that the battery pack may be easily coupled with the device 
and readily removable from the device. Of course, these design goals are 
not unique to consumer devices, but are equally desirable for professional 
cordless devices in which detachable packs have been standard for many 
years. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an 
improved battery pack latch to retain the pack in a cordless device and a 
battery ejecting device embodying the foregoing design objectives. 
In accordance with one aspect of the invention, a battery pack retention 
latch comprises a retaining member to couple with the battery to retain it 
in the device, a release button formed with the retaining member, the 
release button is activated to move the retaining member to a release 
position to enable the battery to be removed from the device, and a spring 
member to bias the retaining member between its coupling or retention 
position and its release position. The spring member is coupled with the 
retaining member. Preferably, the retaining member is L-shaped with the 
release button positioned at the free end of the vertical leg, a cam 
element at the free end of the horizontal leg, and the spring positioned 
in a cut-out in the horizontal leg below the vertical leg. Also, the 
spring member is a helical spring in the cut-out to bias the retaining 
member in a normally engaged position in the device. The cam element has a 
cam face and an opposing retaining face to engage the battery. 
In accordance with a second aspect of the invention, a cordless device 
comprises a cavity with a receptacle in the cavity, a battery pack 
removably located in the cavity with the battery pack including a 
mechanism for electrically coupling with the receptacle and the device 
including a retention latch in accordance with the first aspect of the 
invention described above. 
In accordance with a third aspect of the invention, a cordless device 
comprises a cavity with a receptacle in the cavity, the receptacle is 
adapted to receive a battery, a spring member is positioned in the cavity 
to eject the battery, a holding member is in the cavity to maintain the 
battery in the cavity against the ejecting force of the spring member and 
the device includes a retention latch in accordance with either the first 
aspect of the invention described above or as disclosed herein. 
The latch retains the battery pack in the cavity such that upon release of 
the latch, the battery pack is partially ejected from the cavity by the 
ejecting force of the spring member and is held in the cavity by the 
holding member. 
The holding member includes two embodiments. First, an annular member with 
at least one finger with a detent holds the battery in the cavity against 
the ejecting force. Second, the holding member is coupled with the 
receptacle and includes a plurality of spaced fingers to retain the 
battery against the ejecting force of the spring. Also, the holding member 
is axially slidable in the cavity. 
Additional objects and advantages of the invention will be apparent from 
the detailed description of the preferred embodiment, the appended claims 
and the accompanying drawings or may be learned by practice of the 
invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The preferred embodiment of the present invention is a cordless (i.e. 
battery operated) device, such as a portable electronic device, toy, 
kitchen appliance or power tool. Examples of such a device are a cordless 
screw driver 20 and drill 120 as shown in FIGS. 1, 2 and 8, 9, 
respectively. The preferred embodiment, more particularly, is an improved 
retention latch 50, 140 to retain battery packs 26 in the device 20, 120. 
As shown in FIGS. 1 and 2, in accordance with the present invention, a 
cordless device 20, herein exemplified as an in-line screw driver, 
comprises a housing 24 to receive a battery pack 26, a motor (not shown), 
an output spindle 28, a gear train (not shown) intermediate the motor and 
spindle, and a receptacle 30 to electrically connect battery pack 26 to 
the motor through a motor control circuit (not shown) including on and off 
and speed control switch 32. Housing 24 further includes a generally 
cylindrical cavity 34 and a handle portion 36 of the housing 24 to receive 
battery pack 26 in receptacle 30. Also, the housing 24 includes a pair of 
opposing housing openings 38 and 40 which enable removal of the battery 
pack 26 from the housing 24. Optionally, a spring 23 may be positioned in 
the housing cavity 34 to provide an ejection force to remove the battery 
pack from the housing upon removal of the retention force. 
According to one aspect of the invention, the battery pack 26 is removably 
located in the cavity 34 and is electrically connectable to the receptacle 
30 regardless of the angular orientation of the battery pack 26 about a 
longitudinal axis of symmetry of the pack 26 (this aspect of the invention 
is sometimes hereinafter referred to as the universal angular orientation 
feature). The pack 26 is thus easier to use and may be easily loaded in 
device 20 under adverse conditions such as in dim light or in cramped 
quarters. 
Battery pack 26 is fully described in U.S. patent application Ser. No. 
08/065,736 for "Battery Pack For Cordless Device", filed May 21, 1993, the 
specification and drawings of which are herein expressly incorporated by 
reference. Thus, a detailed description of the battery pack 26 will not be 
given and only those elements which are necessary for the description will 
be described. 
Battery pack 26 comprises an elongated cylindrical tubular metal casing 235 
having opposed rear and forward ends 237 and 239. A plurality of 
electrically connected mechanically disconnected cells 241, 243, 244 are 
disposed end to end in casing 235. For simplicity, pack 26 is illustrated 
in FIG. 2 with three cells 241, 243, 244. However, the present invention 
is equally applicable to packs including two or more cells. Each cell 241, 
243, 244 has a cell can 241a, 243a, 244a for forming a first cell terminal 
and a button terminal 241b, 243b, 244b closing one end of the cell and 
forming a second cell terminal. As is conventional, the first or cell can 
terminal 241a, 243a, 244a is negative and the second or button terminal 
241b, 243b, 244b is positive. The cells 241, 243, 244 are preferably 
nickel cadmium cells which are preferred for high discharge rate 
applications (5 to 30 amps) such as power tools and certain kitchen 
appliances. However, the present invention is also equally applicable to 
other rechargeable and primary cell couples such as nickel, metal hydride 
or primary alkaline cells. 
The top 253 closes the casing forward end 239, is electrically connected to 
button terminal 243b and forms a second pack terminal 254. Top 253 is 
radially symmetrical about the casing axis and defines a cavity 255 in the 
casing forward end 239. A forwardly projecting nipple 257 formed on the 
top 253 is fully recessed within cavity 255 and terminates rearwardly to a 
forward edge of casing 235. Top 253 is electrically connected to and 
mechanically disconnected from forward cell 243 through engagement with 
button terminal 243b. As will be appreciated, first and second pack 
terminals 246, 254 and 255 have opposite polarities (preferably, negative 
and positive, positive, respectively), are coaxial with the casing axis 
and are located adjacent to the casing forward end 239 and, for those 
reasons, pack 26 is easily connectable in the cordless device 20 with 
receptacle 30 regardless of the angular orientation of the pack 26 about 
the pack axis. To electrically insulate each cell 241, 243, 244 from 
casing 235, the cells 241, 243, 244 are enclosed with an electrically 
insulated sleeve 277. 
The cap 29 has a cylindrical wall 31 with an exterior surface and an 
interior diameter to fit over the metal housing of the battery pack 26. 
The cap 29 is secured to the pack 26. The cylindrical wall 31 has an open 
end 33 and a closed dome shaped end 35, however, the closed end could 
likewise be open. The dome end 35 acts as a shock absorber in the event 
the battery is dropped on a surface. Adjacent the open end 33 is an angled 
peripheral surface 25 on the external surface. The angle surface 25 acts 
as a cam to enable passage of the cap 29. A latch keeper groove 27 is 
formed in the external surface of the cylindrical wall 31 to provide an 
engaging recess for the retention latch 50, 140. Gripping members 37 are 
peripherally formed on the exterior surface of the cylindrical wall to aid 
in grasping of the cap 29 to remove the pack 26 from the housing 24. The 
cap includes a bead 39 on its interior surface to secure it with a recess 
281 in the pack casing 235. 
The latch 50 is positioned transversely to the housing 24 to retain the 
battery 26 within the cavity 34. The latch 50 couples with a latch keeper 
groove 27 formed in the battery pack cap 29. The latch 50 includes a latch 
ring 52, a push button 54 and a spring means 56 coupled to latch ring 52. 
In this embodiment, spring means 56 is preferably constituted by forwardly 
extending cantilevered spring arm 56 and is for biasing latch ring 52 
between a normally engaged position (FIG. 4) and a release position (FIG. 
5). Alternatively, spring means 56 may be constituted by a torsion spring 
(not shown) coupled to one side of ring 52 or may be constituted by a 
first forwardly extending cantilevered spring arm and a second rearwardly 
extending cantilevered spring arm. The use of forwardly and rearwardly 
extending arms would be desirable in devices that can accommodate a latch 
of greater length and would have the advantage that the mounting of latch 
ring 52 would be more stable and balanced. The ring 52 is positioned 
within the housing 24 in a groove 60 formed by a pair of radially inwardly 
extending walls 62, 64 in the housing 24 (FIG. 2). Also, the cantilevered 
spring arm 56 is located in a recess 66 in the housing 24. The distal end 
55 of the spring arm 56 is supported on a housing projection 68 to locate 
the latch ring 52 in a normally engaged position. The spring constant of 
spring arm 56 may be easily varied by changing its shape and thickness. 
Also, the spring force of spring arm 56 may be easily varied by changing 
the height or location of projection 68. And thus, latch 50 may be easily 
adapted to the requirements of the embodiment shown in FIGS. 1-7 and other 
applications. 
Turning to FIGS. 3 through 7, the latch 50 is shown. The latch ring 52 
includes ring portions 72, 74, 76 and 78. The first ring portion 72 acts 
as the battery engaging portion which engages the latch keeper groove 27 
formed in the battery pack cap 29. The spring arm 56 extends from this 
portion 72 of the ring 52. The ring portions 74 and 76 are transition 
portions and extend on each side of the continuous ring 52 and include 
reinforcement tabs. To guide movement of ring 52, each ring portion 74, 76 
has a flat outer surface 75, 77 in sliding engagement with a respective 
inner flat web between sidewalls 62, 64. Fourth ring portion 78 opposes 
the first ring portion 72 and includes the unitarily formed push button 
54. As can be seen in the figures, the ring 52 has an elliptical shape 
with a first radius 71 defining the arc of the first ring portion 72 with 
substantially parallel arcs or lines on the ring portions 74 and 76 and a 
second radius 77 defining the arc of the fourth ring portion 78. The radii 
71, 77 of the first and fourth ring portions 72 and 78 are different such 
that the second 74, third 76 and fourth 78 ring portions do not engage the 
battery latch keeper groove 27 in an engaged or disengaged position. Also, 
this design aids in the movement of the latch ring 56 such that when the 
push button 54 is pushed radially of the housing 24, the ring 52 is moved 
laterally downward without bowing its annular portion and is disengaged by 
flexing spring arm 56 in the housing recess 66. Thus, ring 52 is located 
in the disengaged position shown in FIG. 5. The annular portion of the 
ring 52 is guided by and prevented from bowing by the web between side 
walls 62, 64 of the housing 24, as seen in FIG. 2. Further, flat surfaces 
75, 77 aid in reducing friction and prevent rotation of ring 52 about the 
longitudinal axis of handle 36. 
The engagement ring portion 72 includes an angled cam surface 82 which 
assists to enable the battery 26 to pass through the ring 52 as the 
battery cap 29 contacts the cam surface 82, assisting the battery 26 to 
slide through the latch opening 51. 
The latch 50 is ordinarily formed from a polymeric material such as acetel 
forming the latch 50 as a unitary one piece device. However, the latch 50 
may be manufactured from several different parts pieced together to form a 
desired latch member. Also, the latch could be made of a metallic material 
or a metallic material coated with a polymeric material. 
The distal end 55 of the arm 56 is supported on the housing projection 68 
to locate the latch ring 52 in a normally engaged position (FIGS. 1, 2 and 
4). Here, the first ring portion 72 of the ring 52 is engaged on or 
latched in the cap groove 27. When the push button 54 is pushed radially 
inward of the housing, ring 52 is moved laterally downward (without bowing 
its annular position) and is disengaged by flexing spring arm 56 into the 
recess 66. Thereby, ring 52 is located in the disengaged position shown in 
FIG. 6. The annular portion of the ring 52 is prevented from bowing by the 
radially inward housing web between side walls 62, 64 (FIG. 2). 
To insert the battery pack 26 into the housing 24, the battery pack 26 is 
inserted into the housing 24 in any angular orientation and is freely 
slidable in the housing cavity 34 until the first latch ring portion 72 
engages the forward tapered rim 25 of the battery cap 29. The rim 25 
functions as a camming surface with the camming surface 82 of the first 
ring portion 72 and bends arm 56 outwardly as battery pack 26 is manually 
forced into the cavity 34. In this manner, ring 52 slides over rim 25 and 
is biased resiliently inward into the cap groove 27 by spring arm 56 to 
assume the engaged position shown in FIGS. 1, 2 and 4. To disengage 
battery, pack 26 the release button 54 is pushed radially inwardly, 
normally by the user's thumb, to flex spring arm 56 into the housing 
recess 66. Thereafter, battery pack 26 can be pulled axially outwardly 
from the cavity 34 by the index finger on the same hand of the user by 
gripping or grasping the gripping members 37 of the cap 29 through one of 
the opposed housing openings 38, 40. 
In accordance with another feature of the present invention, cordless 
device 120, herein exemplified as a drill, comprises a housing 122 for 
receiving battery packs 26, a motor, not shown, an outer spindle 124, a 
gear train (not shown) intermediate the motor and spindle 124, and a 
receptacle 126 for electrically connecting the battery packs 26 to the 
motor through a motor control circuit (not shown), including on/off and 
speed control switch 128. Springs (not shown) like the one previously 
described could be used to provide an ejection force. Housing 122 further 
includes cylindrical cavities 130 and 132 in a handle portion 134 of the 
housing 122 to receive battery packs 26 in receptacle 128. The battery 
packs 26 are the same as those previously defined with the invention being 
directed to a retention latch 140 positioned within the housing handle 
134. 
The latch 140 comprises a latch double ring 142 mounted in the drill handle 
134 and latch keeper grooves 27 formed in the battery pack caps 29. The 
double ring 142 is located transversely of the handle 134 and is coupled 
to a spring means 144, 146 for biasing latch ring 142 between a normally 
engaged position (FIG. 11) and a release position (FIG. 12). In this 
embodiment, spring means 144, 146 is preferably constituted by a pair of 
forked cantilevered spring arms 144, 146. As in the case of the embodiment 
shown in FIGS. 1-7, the spring means may also be constituted by a torsion 
spring or by forwardly and rearwardly extending spring arms. The ring 142 
is seated in a transverse channel 150 defined by a pair of radially 
extending parallel spaced walls 154 and 156 and is laterally slidable in a 
plane perpendicular to the battery pack axes. The spring arms 144 and 146 
are supported on projections 158 on the interior of the handle 134 to 
locate the latch ring in a normally engaged position, as shown in FIGS. 8, 
9 and 11. 
As shown in the figures, the double ring 142 has an overall open figure 
eight configuration which is open inside the annular regions. Each ring 
160, 162 is C shaped, being connected at one end 164, 166 and being free 
at the other 168, 170. The free ends 168, 170 of the rings 160, 162 
include an integrally or unitarily formed push button 172, 174 which 
enables movement of the latch rings 160, 162. Opposing the push buttons 
172, 174 are engagement portions 176 and 178 of the C shaped rings 160, 
162. The engagement portions 176 and 178 include integrally or unitarily 
formed arcuate flanges 182 and 184 that are latched, respectively, in the 
battery pack grooves 27. The spring arms 144, 146 extend from the engaging 
portion 176, 178 of the C shaped rings 160, 162. Thus, the arms 144, 146 
also oppose the push button members 172, 174. Further, preferably each 
spring arm 144, 146 includes a pair of arms 190, 192, 194, 196. As 
mentioned above, the pair of arms 190, 192, 194, 196 are supported on 
projections 158 to locate the latch ring 142 in a normally engaged 
position as shown in FIG. 11. 
As seen in FIGS. 11 and 12, the pair of integrally formed arcuate flanges 
182, 184 are latched, respectively, in cap grooves 27. The latch 140 is 
designed such that the battery packs 26 can be selectively removed one at 
a time. To disengage one of the packs 26, the push button 172 is pushed 
laterally towards the battery pack 26 by the user's thumb to disengage the 
flange 182 from the cap groove 27 by primarily resiliently bending the 
spring arms 190, 192. The annular portions of the ring 142 are designed 
such that the bending of the annular portions 160 is slight when flexing 
the spring arms 190, 192. Also, the ring 160 may pivot slightly about a 
point 200 when disengaging the flange 182 from the groove 27. Thus, the 
battery 26 may be removed from the cavity 130 by gripping or grasping with 
the index finger of the same hand the gripping member 37 of the cap 29 
through one of the opposed housing openings 202, 204. Regardless, the 
other flange 184 remains engaged in the groove 27 when the push button 172 
is pushed to the disengagement position. The other battery pack 26 is 
removable from the handle 134 by pushing the other push button 174 to 
disengage the flange 184 from the groove 27 in an analogous manner. 
Likewise, the cap 29 would be gripped with an index finger through one of 
the opposing housing openings 206, 208. 
To insert the battery packs 26 in the handle 134, the pack 26 is inserted 
into the handle 134 in any angular orientation and is freely slidable in 
the handle cavities 130, 132 until the flange 182, 184 engages the 
forwardly tapered rim 25 of the cap 29. The cap rim 25 functions as a 
camming surface and bends the spring arm 190, 192, 194, 196 outwardly as 
the battery pack 26 is manually forced into the cavity 130, 132. In this 
manner, flange 182, 184 of the ring 160, 162 slides over the cap rim 25 
and is resiliently biased inward into the cap groove 27 by the spring arm 
190, 192, 194, 196 and somewhat by the other spring arm 194, 196, 190, 192 
to assume the engaged positioned shown in FIG. 11. The other battery pack 
26 may be inserted into the cavity 132, 130 in the handle 134 in an 
analogous manner. 
As mentioned above, the latch 140 can be manufactured from a plethora of 
materials, including polymeric materials such as nylon, metallic materials 
or metallic coated materials. Also, the latch 140 may be a unitary one 
piece device or it may be formed by several independent members. 
Referring to FIGS. 19 through 26, additional embodiments are shown. Like 
elements are identified with the same reference numerals. 
The latch 350 is positioned transversely to the housing 352 to retain the 
battery 26 within the cavity 34. The housing 352 is similar to that 
previously described, however the differences will be described in further 
detail. The latch 350 couples with the latch keeper groove 27 formed in 
the battery cap 29. The latch 350 includes a retaining member 354, a push 
button 356, and a biasing spring 358. 
The retaining member 354 has an overall L-shape when viewed in side 
elevation with the push button 356 at the free end of the vertical leg 360 
and a cam element 362 positioned at the free end of the horizontal leg 
364. The horizontal leg 364 includes a cut-out 366 which retains the 
spring 358 in contact with the retaining member 354. 
The cam element 362 has an overall trapezoidal shape when viewed in front 
elevation. A pair of cam surfaces 370 are inclined and enable passage of 
the battery 26 past the cam element 362 into the cavity 34. Likewise, a 
pair of retaining faces 372 oppose the cam faces 370 which retain and 
block the battery 26 in the keeper groove 27 of the battery cap 29. 
As can be seen in FIGS. 20 and 21, as the push button 356 is activated, 
which in turn compresses the spring 358, the retaining face 372 moves 
transversely with respect to the keeper groove 27 and moves below the 
battery cap 29 whereupon the battery may be removed from the cavity 34. 
The spring 358 is generally a helical spring, however any type of spring 
may be utilized to perform the biasing function. Also, as can be seen, 
other than the spring 358, the latch is formed as a one-piece unit usually 
injection molded from a desired plastic material or the like. 
Also, the vertical leg 360 includes a pair of elongated tabs 374 on its 
longitudinal side edges which retain the latch 350 within grooves 376 
within the housing 352. Thus, the latch 350 is enabled to easily move up 
and down as it is activated and pushed back in position by the biasing 
spring 358. 
Turning to the housing 352, as can be seen, the housing includes a spring 
380 and a electrical receptacle 382. The spring 380 is a helical spring 
which is used to bias the battery 26 out of the cavity upon activation of 
the latch 350. Upon pressing of the push button 356, the spring 380 biases 
the battery out of the housing 352. 
The electrical receptacle 382 includes at least one, preferably a plurality 
of fingers 384 to retain the battery onto the electrical receptacle 382. 
The fingers 384 are compressed together upon receiving the projecting 
nipple 257 on the top 253 of the battery 26. When the nipple 257 contacts 
the fingers 384, the fingers are compressed and exert a retaining gripping 
force onto the projecting nipple 257. The gripping force of the fingers 
384 is larger, in magnitude, than the spring force so that upon activation 
of the latch 350 the spring will eject the battery 26 from the cavity 
while the electrical receptacle 382 retains the battery within the cavity 
so that a portion of the battery is extended from the cavity 34 as seen in 
FIG. 20. Thus, the user can readily grab hold of the battery cap and exert 
a pulling force on the battery cap which overcomes the force of the 
retaining fingers 384 which, in turn, enables removal of the battery from 
the cavity 34. 
Also, the electrical receptacle 382 includes a cylindrical post 386. The 
cylindrical post 386 axially slides in an electrical connector 388 to 
enable electrical receptacle 382 to axially move in the cavity 34 which, 
in turn, enables the battery to be moved partially out of the housing 352. 
The electrical receptacle 382 is ordinarily of an electrical connecting 
material so that proper electrical connection is made between the battery 
and motor of the device. Also, as shown, the spring is positioned 
circumferentially about the cylindrical post 386 connected to a housing 
seat 390 so that the spring pushes on the top of the battery 352. 
Likewise, the fingers could be reverted forming a cavity between the post 
and fingers so that a spring could be positioned within the cavity so that 
the spring could bias the receptacle instead of the battery. 
The housing 352 includes two cavities 34 for holding two batteries. The 
above discussion of the cavity and receptacle apply to both cavities. 
Turning to FIGS. 23 through 26, an additional embodiment is shown. An 
additional housing 390 is illustrated with a retainer latch which is the 
same as latch 50 described above. The housing 390 includes a biasing 
spring 392 to eject the battery 26 from the housing 390 as previously 
explained. Also, the housing includes a holding member 394 which maintains 
the battery 26 in the housing against the force of the spring 392. 
The holding member 394 has an overall annular shape with a ring portion 396 
and at least one, preferably a plurality of extending fingers 398. The 
ring 396 has an annular cam surface 400 which enables the battery 26 to 
pass into the holding member 394. Also, the ring 396 includes a pair of 
tabs 402 which enable the holding member 394 to axially move in slots 404 
of the housing 390. The tabs 402 abut against blocking members 406 in the 
housing 390 which stop the axial movement of the holding member 394 
against the spring force. Thus, the tabs 402 stop the axial movement so 
that the battery 26 only extends a desired distance out of the housing 390 
as illustrated in FIG. 24. 
The fingers 398 extend from the ring 396 and have a curved end 410. Also, 
the fingers include an interior extending detent 412. As the battery 26 
passes into the holding member 394, the top 352 of the battery casing 
abuts the curved ends 410 of the fingers and the detent 412 snaps into the 
radial groove on the battery top 253. 
The spring 392 exerts a force on the curved ends 410 of the holding member 
which in turn move the holding member 394 axially in the housing. The tabs 
402 abut the stops 406 whereupon the battery extends a desired distance 
out of the cavity. Thus, the user can grab the cap 29 of the battery, pull 
on the battery overcoming the force of the detents 412, pushing the 
fingers 398 outward and enabling the battery to be removed from the cavity 
34. 
Turning to FIGS. 27 through 29, an additional embodiment is shown. A 
terminal assembly 420 is illustrated including an insulating support 422, 
a negative terminal 424 and a positive terminal 426. The negative and 
positive terminals 424, 426 are rivoted to the insulative support board 
422. The positive terminal 426 includes a pair of extending fingers 428 
which engage the battery pack terminal, thus electrically connecting the 
battery to the motor. 
The negative terminal 424 includes an arcuate base 429 terminating in a 
spring portion 430 for ejecting the battery pack 26. Also, the negative 
terminal includes a cantilevered arm 432 which serves as an electrical 
connection to the battery pack sidewall. Also, the cantilever arm 432 
includes a detent 434 which engages the annular recess in the battery pack 
26. 
Turning to FIG. 28, the battery pack is illustrated in a latched position. 
In this position, the spring arm 430 is flattened and the cantilevered arm 
detent 434 is disengaged from the annular recess 436 in the battery pack 
26. As shown, the positive terminal 426 is engaged with the battery pack 
terminal. 
FIG. 29 illustrates the battery pack in an unlatched position. In the 
unlatched position, the spring portion 430 returns to its relaxed position 
which, in turn, ejects the battery pack 26 from the housing 24. As the 
battery pack 26 is ejected from the housing, the cantilevered arm detent 
434 engages the annular recess in the battery 26 to retain the battery 
pack 26 in the housing. As can be seen, a portion of the battery pack 26 
extends from the housing 24 so that the user may readily grab the battery 
and pull it from the housing which overcomes the retention force of the 
cantilevered arm 432 to enable the battery to be pulled from the housing. 
By eliminating retention latch from the battery itself and positioning the 
latch within the housing, the batteries may be smaller and are able to 
nest with one another in a group in close proximity to one another. Also, 
the latch is more durable when enclosed in the housing, prohibiting easy 
break off like that which occurs when the latch is on the battery. Other 
advantages will be apparent to those skilled in the art. 
It will be recognized that although latches 50, 140 have been described as 
preferably generally annular or circular, other configurations may be used 
consistent with the geometry of the device in which the latch is used. For 
example, rectangular and octagonal configurations may be used. Such 
configurations may also be open to form a generally C-shaped 
configuration, if desired. 
It will be apparent to those skilled in the art that various modifications 
and variations may be made in the cordless device and latch of the present 
invention without departing from the scope or the spirit of the present 
invention. Thus, it is intended that the present invention cover these 
modifications and variations provided they come within the scope of the 
appended claims and their equivalents.