Transmission devices for locks with changeable lock core assemblies

A lock assembly includes a handle assembly including a tubular member having an axial hole defined in a first end thereof and extending along a longitudinal axis thereof and a receptacle defined in a second end thereof and in communication with the axial hole, and a handle formed on the second end of the tubular member. A lock core assembly is removably mounted to the receptacle of the handle assembly and includes a lock core therein. The lock core includes a key hole defined in a first end thereof. A transmission device is received in the axial hole of the tubular member and includes a first end and a second end. The second end of the transmission device includes an end face plate extending in a direction transverse to a longitudinal axis of the key driving means, and two spaced positioning rods project outwardly from the end face plate and extend away from the first end along a direction parallel to the longitudinal axis of the transmission device. The lock core includes two positioning holes defined in a second end thereof and extending along a direction parallel to a longitudinal axis thereof. The positioning rods are removably extended through the holes in the second end of the lock core. The holes are respectively aligned with the positioning rods when mounting the lock core assembly into the receptacle.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to transmission devices for locks with 
changeable lock core assemblies and, more particularly, to transmission 
devices for locks with changeable lock core assemblies which allow easy, 
smooth operation during change of the lock core assemblies and which are 
simple in structures, easy in installation, and low in cost. 
2. Description of the Related Art 
Generally, locks include different types of structures responsive to 
different needs and different users, e.g., lever locks, trumpet locks, 
auxiliary locks, etc., wherein the lever locks and the trumpet locks are 
primary locks while the auxiliary locks provide further security in 
addition to the lever locks and the trumpet locks. 
The lock core assemblies of traditional locks cannot be dismantled. FIGS. 1 
and 2 of the drawings illustrate a conventional lever lock in which 
rotation of either handle "A" causes rotation of a wing-like driving 
member "C" of a tubular member "B", which, in turn, causes retraction or 
protruding movement of a latch bolt via transmission of an actuating 
member "D", thereby locking or unlocking the door to which the lever lock 
is mounted. The lock core assembly of the lever lock cannot be dismantled. 
Trumpet locks include similar structures and, therefore, the lock core 
assemblies thereof are also undetachable. 
For safety consideration, house renters and hotel managers often change the 
locks after the previous tenants and guests have returned the keys, 
thereby improving security and preventing burglary and theft invents. Yet 
replacement of the whole lock is time-consuming. In addition, frequent 
replacements result in a decrease in the life-periods of the locks. 
FIG. 3 of the drawing illustrates a conventional auxiliary lock which is 
commonly used in important departments of public places. However, same 
problems exist, especially in the case of transfer or resignation of the 
staff or there is a change in the employees in which all of the locks in 
the working area must be changed periodically, thereby avoiding loss of 
property due to unauthorized copying of the keys. 
In view of the above-mentioned problems, locks having changeable lock core 
assemblies have been developed to meet the needs of different users, in 
which a lock core assembly can be removed from or inserted into the lock 
via a front side of the lock without detachment of any other elements of 
the lock. Generally, a lock with a changeable lock core assembly requires 
two keys, one of which can be operated to open or close the door to which 
the lock is mounted, while the other one of which is specifically used for 
change of the lock core assembly. However, it is found that a positioning 
protrusion of a transmission device of the lock cannot be effectively 
positioned after removal of the lock core assembly. More specifically, the 
positioning protrusion cannot be aligned with a hole of the lock core 
assembly during installation as the former is deviated by an angle or 
inclined, or due to rotation of either handle. Therefore, manufactures 
often annex a pushing rod to the packaged lock for users such that the 
user may use the pushing rod to push the positioning protrusion to a 
position in alignment with the hole of the lock core assembly for 
installation of the later. Nevertheless, it is still inconvenient for 
users. 
Therefore, there has been a long and unfulfilled need for an improved lock 
with a changeable lock core assembly which mitigates and/or obviates the 
above-mentioned problems. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a transmission device 
for a lock with a changeable lock core assembly in which replacement of 
the lock core assembly of, e.g., a lever lock or trumpet lock, can be 
easily, smoothly accomplished. 
It is another object of the present invention to provide a transmission 
device for an auxiliary lock such that the auxiliary lock may include a 
changeable lock core. 
In accordance with one aspect of the invention, a transmission device is 
provided for a lock assembly which comprises a handle assembly including: 
a tubular member having a first end, a second end, and a longitudinal axis, 
the first end of the tubular member including an axial hole defined 
therein and extending along the longitudinal axis of the tubular member, 
the second end of the tubular member including a receptacle defined 
therein and in communication with the axial hole, a handle being formed on 
the second end of the tubular member, a lock core assembly being removably 
mounted in the receptacle of the handle assembly and including a lock core 
therein, the lock core including a first end, a second end, and a 
longitudinal axis, the first end of the lock core having a key hole 
defined therein; and 
means for releasably retaining the lock core assembly in the receptacle 
upon rotation of the lock core assembly. 
The transmission device comprises: 
a key driving means received in the axial hole of the tubular member and 
including a first end and a second end, the second end of the key driving 
means including an end face plate extending in a direction transverse to a 
longitudinal axis of the key driving means, two spaced positioning rods 
projecting outwardly from the end face plate and extending away from the 
first end along a direction parallel to the longitudinal axis of the key 
driving means; and 
the second end of the lock core having two positioning holes defined 
therein and extending along a direction parallel to the longitudinal axis 
of the lock core, the positioning rods being removably extended through 
the holes in the second end of the lock core, wherein the holes are 
respectively aligned with the positioning rods when mounting the lock core 
assembly into the receptacle. (FIG. 4) 
In accordance with a further aspect of the invention, a transmission device 
is provided for a lock assembly which comprises a handle assembly 
including: 
a tubular member including therein a transverse plate which extends in a 
direction transverse to a longitudinal axis of the tubular member, the 
transverse plate being movable between a first position which is partially 
extended beyond the tubular member and a second position which is 
retracted into the tubular member; 
a handle including a first end, a second end, and a longitudinal axis, the 
first end of the handle including an axial hole defined therein and 
extending along the longitudinal axis of the handle for partially 
receiving the tubular member, the second end of the handle including a 
receptacle defined therein and in communication with the axial hole, the 
handle further including a peripheral wall having a positioning slot 
defined therein through which the transverse plate is partially extended 
to the first position thereof, thereby engaging the handle with the 
tubular member, a lock core assembly being removably mounted to the 
receptacle of the handle assembly and including a lock core therein, the 
lock core including a first end, a second end, and a longitudinal axis, 
the first end of the lock core having a key hole defined therein; and 
means for releasably retaining the lock core assembly in the receptacle 
upon rotation of the lock core assembly. 
The transmission device comprises: 
a key driving means including a key driving tubular member and a 
transmission member, the key driving tubular member including a first end, 
a second end, and a longitudinal axis, the transmission member including a 
first end removably attached to the second end of the key driving tubular 
member and a second end, two spaced positioning rods projecting outwardly 
from the second end of the transmission member; and 
the second end of the lock core having two positioning holes defined 
therein and extending along a direction parallel to the longitudinal axis 
of the lock core, the positioning rods being removably extended through 
the holes in the second end of the lock core, wherein the holes are 
respectively aligned with the positioning rods when mounting the lock core 
assembly into the receptacle. 
In one embodiment of the invention, the second end of the key driving 
tubular member includes a plate mounted therein and extending in a 
direction transverse to the longitudinal axis of the key driving tubular 
member. The plate includes an opening defined therein, and the 
transmission member includes a disc having a first side, a second side, 
and a longitudinal axis. An insert plate projects outwardly from the first 
side of the disc and extends along the longitudinal axis of the disc. The 
two spaced positioning rods project outwardly from the second side of the 
disc and extend along a direction parallel to the longitudinal axis of the 
disc. The insert plate is removably received in the opening of the plate 
in the key driving tubular member. (FIG. 5) 
In another embodiment of the invention, the disc includes a central 
opening. The insert plate is releasably extended through the central 
opening to the second side of the disc, and the positioning rods project 
from an end of the insert plate located at the second side of the disc. 
The insert plate further includes a stop formed on a mediate section of 
each of two longitudinal sides thereof. (FIG. 14) 
In a further embodiment of the invention, the disc further includes a 
second plate projecting outwardly from the second side thereof and 
extending along the longitudinal axis thereof. The transverse plate in the 
tubular member rests on a side of the second plate to prevent the 
transverse plate from being moved into the tubular member due to an 
external force, thereby preventing disengagement of the tubular member 
from the handle. When the transmission member is rotated through a 
pre-determined angle, the transverse plate is moved into the second 
position within the tubular member such that the tubular member is 
disengaged from the handle, thereby allowing removal of the handle. (FIG. 
7) 
In a still another embodiment, the disc includes a central opening, and the 
insert plate and the second plate are integral and releasably extended 
through the central opening and respectively located at the first side and 
the second side of the disc. The integral insert plate/second plate 
further includes a stop formed on a mediate section of each of two 
longitudinal sides thereof. (FIG. 13) 
In a yet another embodiment of the invention, the disc further includes a 
second plate projecting outwardly from the second side thereof and 
extending along the longitudinal axis thereof, and the positioning rods 
project from the second plate located at the second side of the disc. 
(FIG. 15) 
In a modified embodiment of the invention, the disc includes a cruciform 
central opening, and the insert plate and the second plate are integral 
and releasably extended through the central opening and respectively 
located at the first side and the second side of the disc. The integral 
insert plate/second plate further includes a stop formed on a mediate 
section of each of two longitudinal sides thereof. (FIG. 16) 
In a still another embodiment of the invention, the second end of the key 
driving tubular member includes two diametrically extending grooves 
defined therein, the two grooves being perpendicular to each other. The 
disc includes two opposed lateral sides, and two engaging blocks are 
respectively formed on the two opposed lateral sides of the disc for 
releasably engaging one of the two diametrically extending grooves in the 
key driving tubular member. (FIG. 9; FIG. 11) 
Preferably, the disc further includes at least one knurl projecting from a 
side thereof. The transverse plate in the tubular member rests on the 
knurl to prevent the transverse plate from being moved into the tubular 
member due to an external force, thereby preventing disengagement of the 
tubular member from the handle. When the transmission member is rotated 
through a pre-determined angle, the transverse plate is moved into the 
tubular member such that the tubular member is disengaged from the handle, 
thereby allowing removal of the handle. 
In accordance with a further aspect of the invention, a transmission device 
for a lock assembly which comprises: 
a sleeve including a first end and a second end, the sleeve further 
including a first hole and a second hole which is in communication with 
the first hole, the first and second holes together forming a receptacle 
for receiving a lock core assembly, a bore being defined in the second end 
of the sleeve and in communication with the second hole, a protrusion 
section being formed along a periphery defining the bore; 
The transmission device connects the lock core assembly with the sleeve and 
comprises: 
a positioning member including a plate which is attached to a bottom end 
wall defining the second hole and which has a central opening defined 
therein, the plate including two spaced positioning rods projecting from 
two opposed longitudinal sides thereof and extending away from the bottom 
end wall defining the second hole along a direction parallel to a 
longitudinal axis of a lock core of the lock core assembly received in the 
receptacle of the sleeve, the plate further including a protrusion which 
is formed on a lateral side thereof and which is received in the bore of 
the sleeve, the positioning rods being extended through two holes defined 
in the lock core of the lock core assembly and extending along a direction 
parallel to the longitudinal axis of the lock core; 
a transmission element having a relatively large first end and a relatively 
small second end, the second end of the transmission element being 
extended through the central opening of the positioning member beyond the 
sleeve; and 
a rotational positioning element received in the second end of the sleeve, 
the rotational positioning element including an opening through which the 
second end of the transmission element extends, and a protrusion being 
formed around the opening and received in the bore of the sleeve. 
The transmission element may include a stop knurl formed on a lateral side 
thereof adjacent to the first end thereof, and movements of the 
positioning member and the rotational positioning element are restrained 
between the first end of the transmission element and the stop knurl. 
Other objects, advantages, and novel features of the invention will become 
more apparent from the following detailed description when taken in 
conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIGS. 3 to 20 and initially to FIG. 4, in which an exploded 
perspective view of a first embodiment of a transmission device in 
accordance with the present invention applied to a lever lock is shown. It 
is appreciated that the transmission device can be applied to a trumpet 
lock in addition to the lever lock. As can be seen in FIG. 4, the lever 
lock includes a handle assembly 3 and a transmission device. The handle 
assembly 3 includes a tubular member having a first end 310 and a second 
end 320. The first end 310 includes an axial hole 330 defined therein and 
extending along a longitudinal axis of the tubular member, while the 
second end 320 includes a substantially "8" shaped receptacle 340 defined 
therein and in communication with the axial hole 330. The second end 320 
further includes an engaging means (not shown) mounted therein and a 
lever-type handle (not labeled) extending therefrom. The first end 310 is 
connected to and thus actuates an actuating member (not shown) in the 
lever lock. 
The transmission device includes a key driving means 5 which is cylindrical 
and includes a first end 510 and a second end 520. The second end 520 
includes an end face plate 530 extending in a direction transverse to a 
longitudinal axis of the key driving means 5. Two spaced positioning rods 
540 project outwardly from the end face plate 530 and extend away from the 
first end 510 along a direction parallel to the longitudinal axis of the 
key driving means 5. 
A lock core assembly 1 is removably mounted in the "8" shaped receptacle 
340 and includes a lock core 11 therein. The lock core 11 includes a key 
hole 12 to allow insertion of a key 9. The lock core 11 further includes 
two spaced holes 13 which are defined in an end opposite to the key hole 
12 and which extend along a direction parallel to a longitudinal axis of 
the lock core assembly 1. The lock core assembly 1 further includes a 
protrusion 14 formed on an outer periphery thereof for positioning of the 
lock core assembly 1 in the receptacle 340. 
In assembly, the key driving means 5 is received in the axial hole 330 of 
the handle assembly 3, wherein the positioning rods 540 of the key driving 
means 5 are extended into the "8" shaped receptacle 340. Then, the lock 
core assembly 1 is inserted into the "8" shaped receptacle 340 with the 
positioning holes 13 of the lock core assembly 1 in alignment with the 
positioning rods 540. Rotation of the key 9 for changing the lock core 
assembly 1 causes rotation of the whole lock core assembly 1 in a 
direction that the protrusion 14 may be engaged with an engaging means 
(not shown) of the handle assembly 3, thereby achieving positioning of the 
lock core assembly 1 in the "8" shaped receptacle 340. For normal locking 
and unlocking operation of the lever lock, a different key therefor (not 
shown) may be inserted into the key hole 12 to rotate the lock core 11, 
which, in turn, actuates the actuating member (not shown) via transmission 
of the key driving means 5, thereby locking or unlocking the lever lock. 
When changing the lock core assembly 1 is required, the key 9 is inserted 
and rotated through a pre-determined angle in an opposite direction to 
disengage the protrusion 14 from the engaging means (not shown) of the 
handle assembly 3, and the lock core assembly 1 is then removable from the 
"8" shaped receptacle 340, which is conventional and therefore not further 
described. 
The first embodiment can be modified so as to be applied to a trumpet lock. 
FIGS. 5 and 6 illustrate a second embodiment of the present invention, in 
which the trumpet lock includes a handle assembly and a transmission 
device. The handle assembly comprises a tubular member 32 and a knob-type 
handle 33. The transmission device includes a key driving means which, in 
turn, includes a key driving tubular member 51 and a transmission member 
52. 
The tubular member 32 includes therein a transverse plate 321 which extends 
in a direction transverse to a longitudinal axis of the tubular member 32 
and which is located between two ends of the tubular member 32. The 
transverse plate 321 may be partially extended beyond a wall of the 
tubular member 32 or retracted into the tubular member 32. An elastic 
member (not shown) is provided to bias the transverse plate 321 to make 
the transverse plate 321 partially extend beyond the wall of the tubular 
member 32. 
The handle 33 includes a first end 331 and a second end 332. The first end 
331 includes an axial hole 333 defined therein and extending along a 
longitudinal axis of the handle 33 for receiving an end of the tubular 
member 32, while the second end 332 includes a substantially "8" shaped 
receptacle 334 defined therein and in communication with the axial hole 
333. The second end 332 further includes an engaging means (not shown) 
mounted therein. As shown in FIG. 6, the handle 33 includes a peripheral 
wall having a positioning slot 335 defined therein. The above-mentioned 
transverse plate 321 may be partially extended through the positioning 
slot 335, thereby engaging the handle 33 with the tubular member 32 
together. 
The key driving tubular member 51 is cylindrical and includes a first end 
511 and a second end 512. The second end 512 includes a plate 513 mounted 
therein and extending in a direction transverse to a longitudinal axis of 
the key driving tubular member 51. The plate 513 includes an opening 514 
defined therein. 
The transmission member 52 includes a disc 521 having a first side and a 
second side. An insert plate 522 projects outwardly from the first side 
and extends along a longitudinal axis of the disc 521. Two spaced 
positioning rods 523 project outwardly from the second side and extend 
along a direction parallel to the longitudinal axis of the disc 521. 
Preferably, the insert plate 522 and the positioning rods 523 extend on 
the same plane. The insert plate 522 is removably received in the opening 
514 of the plate 513 in the key driving tubular member 51. As shown in 
FIG. 6, the transverse plate 321 in the tubular member 32 rests on a side 
of one of the positioning rods 523, thereby preventing the transverse 
plate 321 from being moved into the tubular member 32 due to an external 
force which may cause disengagement of the tubular member 32 from the 
handle 33. Yet, if the transmission member 52 is rotated through a 
predetermined angle, the transverse plate 321 is moved into the tubular 
member 32 such that the tubular member 32 is disengaged from the handle 
33, thereby allowing removal of the handle 33. 
Assembly of the second embodiment is substantially the same as that of the 
first embodiment. It is appreciated that, as shown in FIG. 6, the 
transverse plate 321 of the tubular member 32 and the plate 513 in the key 
driving tubular member 51 may tightly, securely retain the disc 521 of the 
transmission member 52 in position in a manner that the longitudinal axes 
of the positioning rods 523 of the transmission member 52 are 
substantially parallel to the longitudinal axis of the tubular member 32, 
thereby allowing easy insertion of a lock core assembly 1 into the tubular 
member 32 by means of the positioning rods 523 respectively and smoothly 
received in two positioning holes 13 of a lock core 11 (see FIG. 5) of the 
lock core assembly 1. 
FIGS. 7 and 8 illustrate a third embodiment of the present invention, in 
which the substantially "8" shaped lock core assembly 1 for the lever lock 
illustrated therein is identical to the lock core assembly 1 for the 
trumpet lock in FIGS. 5 and 6, except for that there is a 90 degrees 
difference in installation angle. The key driving tubular member 51 and 
the tubular member 32 in this embodiment are identical to those disclosed 
in FIGS. 5 and 6 and therefore not further described. The knob-like handle 
33 in FIGS. 5 and 6 is changed to a lever-like handle 31, and like 
elements thereof are designated by like reference numerals except by 
different leading numerals (i.e., "333" is changed to "313", "331" is 
changed to "311", etc.). 
The transmission member 53 in this embodiment includes a disc 531 having a 
first side and a second side. An insert plate 533 projects outwardly from 
the first side and extends along a longitudinal axis of the disc 531. Two 
spaced positioning rods 532 project outwardly from the second side and 
extend along a direction parallel to the longitudinal axis of the disc 
531. A second plate 534 projects outwardly from the second side and 
extends between the positioning rods 532 and along the longitudinal axis 
of the disc 531. Preferably, the insert plate 533 and the second plate 534 
extend on the same plane, while the positioning rods 532 lie on a plane 
perpendicular to the insert plate 533. The insert plate 533 is removably 
received in the opening 514 of the plate 513 in the key driving tubular 
member 51. As shown in FIG. 8, the transverse plate 321 in the tubular 
member 32 rests on a side of the second plate 534, thereby preventing the 
transverse plate 321 from being moved into the tubular member 32 due to an 
external force which may cause disengagement of the tubular member 32 from 
the handle 31. Yet, if the transmission member 53 is rotated through a 
predetermined angle, the transverse plate 321 is moved into the tubular 
member 32 such that the tubular member 32 is disengaged from the handle 
31, thereby allowing removal of the handle 31. 
Assembly of the third embodiment is substantially the same as that of the 
second embodiment, the only difference therebetween is that the knob-like 
handle 33 is changed to the lever-like handle 31, wherein a longitudinal 
plane of the "8" shaped receptacle 334 of the knob-like handle 33 is 
perpendicular to that of the "8" shaped receptacle 314 of the lever-like 
handle 31 such that the installation degree therefor is rotated through 90 
degrees. Nevertheless, for the whole transmission device, it is only 
required to modify the transmission member 52 to the transmission member 
53 which has been hereinbefore described. 
FIGS. 9 to 12 illustrate a fourth embodiment of a transmission device in 
accordance with the present invention, in which the transmission device 
(i.e., the key driving means) may be applied to either a lever lock (FIGS. 
9 and 10) or a trumpet lock (FIGS. 11 and 12) 
In FIGS. 9 to 12, the transmission device (i.e., the key driving means) 
includes a key driving tubular member 54 and a transmission member 55. The 
key driving tubular member 54 includes a first end 541 and a second end 
542. The second end 542 includes two diametrically extending grooves 543 
defined therein. The two grooves 543 are perpendicular to each other. A 
block 544 is formed in an end of each of the grooves 543. The transmission 
member 55 includes a disc 551 having two spaced positioning rods 552 
projecting from two opposed longitudinal sides thereof and extending away 
from the second end 542 of the key driving tubular member 54 along a 
longitudinal axis of the transmission member 55. Two engaging blocks 553 
are respectively formed on two opposed lateral sides of the disc 551. The 
disc 551 further includes two knurls 554 projecting from a side thereof 
along a direction of which the positioning rods 552 extend. 
When applied to a lever lock, as shown in FIGS. 9 and 10, the two engaging 
blocks 553 of the disc 551 are received in the horizontally extending 
groove 543 in FIG. 9. As shown in FIG. 10, the transverse plate 321 in the 
tubular member 32. rests on one of the knurls 554, thereby preventing the 
transverse plate 321 from being moved into the tubular member 32 due to an 
external force which may cause disengagement of the tubular member 32 from 
the handle 31. Yet, if the transmission member 55 is rotated through a 
pre-determined angle, the transverse plate 321 is moved into the tubular 
member 32 such that the tubular member 32 is disengaged from the handle 
31, thereby allowing removal of the handle 31. Furthermore, each of the 
longitudinal sides of the disc 551 is indented in a mediate portion 
thereof (see FIG. 9), such that the disc 551 of the transmission member 55 
can be securely held in a space defined between the blocks 544 of the key 
driving tubular member 54 and the transverse plate 321 of the tubular 
member 32, thereby assuring that the longitudinal axes of the positioning 
rods 552 are parallel to the longitudinal axis of the tubular member 32. 
When applied to a trumpet lock, as shown in FIGS. 11 and 12, the two 
engaging blocks 553 of the disc 551 are received in the vertically 
extending groove 543 in FIG. 11 (by means of simply rotating the 
transmission member 55 in FIG. 9 through 90 degrees). As shown in FIG. 12, 
the transverse plate 321 in the tubular member 32 rests on a side of one 
of the positioning rods 552, thereby preventing the transverse plate 321 
from being moved into the tubular member 32 due to an external force which 
may cause disengagement of the tubular member 32 from the handle 31. Yet, 
if the transmission member 55 is rotated through a pre-determined angle, 
the transverse plate 321 is moved into the tubular member 32 such that the 
tubular member 32 is disengaged from the handle 31, thereby allowing 
removal of the handle 31. Again, each of the longitudinal sides of the 
disc 551 is indented in a mediate portion thereof (see FIG. 11), such that 
the disc 551 of the transmission member 55 can be securely held in a space 
defined between the blocks 544 of the key driving tubular member 54 and 
the transverse plate 321 of the tubular member 32, thereby assuring that 
the longitudinal axes of the positioning rods 552 are parallel to the 
longitudinal axis of the tubular member 32. 
FIG. 13 illustrates a modified embodiment of the transmission member of the 
third embodiment (cf. FIG. 7) of the transmission device, wherein the 
transmission member 53 (see FIG. 7) may comprise two parts: a connecting 
plate 56 and a transmission element 57. The connecting plate 56 is 
substantially rectangular and includes a first end 561 and a second end 
562. A stop 563 is formed on a mediate section of each of two longitudinal 
sides of the connecting plate 56. The transmission element 57 includes a 
disc 571 having a central opening 572 defined therein through which the 
second end 562 of the connecting plate 56 extends. The disc 571 includes 
two spaced positioning rods 573 projecting from two opposed longitudinal 
sides thereof and extending away from the stops 563 of the connecting 
plate 56 along a direction parallel to a longitudinal axis of the disc 
571. The second end 562 of the connecting plate 56 may be extended through 
the central opening 572 of the disc 571 until the stops 563 bear against a 
periphery defining the central opening 572 of the disc 571, thereby 
forming an integral unit. 
FIG. 14 illustrates a modified embodiment of the transmission member of the 
second embodiment (cf. FIG. 5) of the transmission device, wherein the 
transmission member may comprise two parts: a positioning disc 59 and a 
transmission element 58. The positioning disc 59 is substantially a 
circular disc 591 with a central opening 592 defined therein. The 
transmission element 58 is substantially a rectangular plate which 
includes a first end 581 and a second end 582. A stop 583 is formed on a 
mediate section of each of two longitudinal sides of the transmission 
element 58. The transmission element 58 further includes two spaced 
positioning rods 584 projecting from the second end 582 thereof and 
extending away from the stops 583 along a direction parallel to a 
longitudinal axis of the transmission element 58. The second end 582 as 
well as the positioning rods 584 of the transmission element 58 may be 
extended through the central opening 592 of the disc 591 until the stops 
583 bear against a periphery defining the central opening 592 of the disc 
591, thereby forming an integral unit. 
FIG. 15 illustrates a fifth embodiment of the present invention which is 
modified from the transmission member 53 of the third embodiment. As can 
be seen in FIG. 15, the transmission member, which is now designated by 
reference numeral "41", includes a disc 411 having a first side and a 
second side. A first plate 412 projects outwardly from the first side and 
extends along a longitudinal axis of the disc 411. A second plate 413 
projects outwardly from the second side and extends along the longitudinal 
axis of the disc 411. Two spaced positioning rods 414 project outwardly 
from the second plate 413 and extend along a direction parallel to the 
longitudinal axis of the disc 413. Assembly and operation of the fifth 
embodiment are the same as those of the third embodiment and are therefore 
not redundantly described. 
FIG. 16 illustrates a modified embodiment of the transmission member of the 
fifth embodiment (cf. FIG. 15) of the transmission device, wherein the 
transmission member comprises two parts: a positioning disc 42 and a 
transmission element 43. The positioning disc 42 is substantially a 
circular disc 421 with a central cruciform opening 422 defined therein. 
The transmission element 43 is substantially a rectangular plate which 
includes a first end 431 and a second end 432. A stop 433 is formed on a 
mediate section of each of two longitudinal sides of the transmission 
element 43. The transmission element 43 further includes two spaced 
positioning rods 434 projecting from the second end 432 thereof and 
extending away from the stops 433 along a direction parallel to a 
longitudinal axis of the transmission element 43. The second end 432 as 
well as the positioning rods 434 of the transmission element 43 may be 
extended through the central cruciform opening 422 of the disc 421 until 
the stops 433 bear against a periphery defining the central cruciform 
opening 422 of the disc 421, thereby forming an integral unit. 
FIGS. 17 to 19 illustrate a further embodiment of the transmission device 
in accordance with the present invention which is applied to an auxiliary 
lock. The transmission device, which is used to connect a lock core 
assembly 100 (see FIG. 17) of an auxiliary lock with a sleeve 6 of the 
auxiliary lock, includes a positioning member 7, a transmission element 8, 
and a rotational positioning element 9. 
The sleeve 6 is substantially cylindrical and includes a first end 61 and a 
second end 62. The sleeve 6 further includes a first hole 63 and a second 
hole 64 which is in communication with the first hole 63. The first and 
second holes 63 and 64 together form a substantially "8" shaped receptacle 
for receiving the lock core assembly 100. A bore 65 is defined in the 
second end 62 of the sleeve 6 and is in communication with the second hole 
64, as shown in FIG. 18. A protrusion section 66 is formed along a 
periphery defining the bore 65. 
The positioning member 7 is substantially a plate which is attached to a 
bottom end wall defining the second hole 64 and which has a central 
opening 71 defined therein. The plate includes two spaced positioning rods 
72 projecting from two opposed longitudinal sides thereof and extending 
away from the bottom end wall defining the second hole 64 along a 
direction parallel to a longitudinal axis of a lock core 103 of the lock 
core assembly 100 received in the "8" shaped receptacle of the sleeve 6. 
The plate further includes a protrusion 73 which is formed on a lateral 
side thereof and which is received in the bore 65 of the sleeve 6. The 
positioning rods 72 may be extended through two holes 101 defined in the 
lock core 103 of the lock core assembly 100 and extending along a 
direction parallel to the longitudinal axis of the lock core 103. 
The transmission element 8 is substantially a rod having a relatively large 
first end 81 and a relatively small second end 82. The second end 82 is 
extended through the central opening 71 of the positioning member 7 beyond 
the sleeve 6. 
The rotational positioning element 9 is substantially a disc received in 
the second end 62 of the sleeve 6. The rotational positioning element 9 
includes an opening 91 through which the second end 82 of the transmission 
element 8 extends. Nevertheless, it is appreciated that the rotational 
positioning element 9 and the transmission element 8 can be made together 
by fitting engagement, riveting, welding, gluing, etc. A protrusion 92 is 
formed around the opening 91 and can be received in the bore 65 of the 
sleeve 6. Alternatively, the protrusion 92 can be replaced by a plurality 
of aligned knurls. 
In assembly, the second end 82 of the transmission element 8 is extended 
through the opening 71 of the positioning member 7, and the first end 81 
of the transmission element 8 bears against the positioning member 7. 
Then, positioning member 7 and the transmission element 8 are inserted 
into the second hole 64 of the sleeve 6, in which the second end 82 of the 
transmission element 8 is extended beyond the second end 62 of the sleeve 
6, while the protrusion 73 of the positioning member 7 is received in the 
bore 65 of the sleeve 6. The second end 82 of the transmission element 8 
is fittingly extended through the opening 91 of the rotational positioning 
element 9, and the protrusion 92 of the rotational positioning element 9 
is received in the bore 65 of the sleeve 6 and spaced from the protrusion 
73 of the positioning member 7. Thereafter, for insertion of the lock core 
assembly 100, the holes 101 of the lock core 103 are aligned with the 
positioning rods 72 of the positioning member 7 and moved along a 
longitudinal axis of the lock core 103 until the lock core 103 is received 
in the receptacle of the sleeve 6 defined by the first and second holes 63 
and 64 of the sleeve 6. When a key (not shown) for locking and unlocking 
is inserted into a key hole (not labeled) of the lock core 103 and rotated 
through a predetermined angle, the protrusion 73 of the positioning member 
7 bears against the protrusion 92 of the rotational positioning element 9 
to make the rotational positioning member 9 and the transmission element 8 
rotate together, thereby causing a portion of the second end 82 of the 
transmission element 8 to engage with a latch bolt (not shown) to move 
therewith. 
FIG. 20 illustrates a modified embodiment of the transmission device in 
FIG. 17, in which a stop knurl 83 is formed on the transmission element 8 
adjacent to the first end 81, such that the positioning member 7 and the 
rotational positioning element 9 are restrained between the first end 81 
and the stop knurl 83. 
Although the invention has been explained in relation to its preferred 
embodiment, it is to be understood that many other possible modifications 
and variations can be made without departing from the spirit and scope of 
the invention as hereinafter claimed.