Combination lock

A cylinder type combination lock comprising a housing formed with windows arranged in a row, a corresponding number of disk dials accommodated in the housing for respective rotation therein, each dial having a slit and an operation lever projecting through the concerned window for angularly moving the dials, and a key-like member insertable in the housing, wherein the angular positions of the slits relative to the respective operation lever are formed in such a way that by setting the operation levers in a predetermined arrangement of various angular positions, all slits are put in alignment for unlocking.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to a combination lock formed with a 
plurality of disk dials to be operated for locking or unlocking. 
In general, there are two types of such combination locks. One is of a 
padlock type having a shackle. The other is of a cylinder type which 
comprises a first body of a cylindrical configuration formed with a key 
bore open at one end thereof and connected at the other end thereof with 
one end of a chain, wire cable or the like loop member, and a second body 
to be connected with the other end of the loop member and having a 
key-like projection to be inserted in the first body through the key bore. 
The present invention relates particulalry to the latter type combination 
lock. 
The invention further relates to a cylinder type combination lock which may 
allow for a user to select a desired dial combination for unlocking. 
2. Description of the Prior Art 
Various cylinder type combination locks have been proposed and widely 
employed for lacking bicycles and the like. For instance U.S. Design Pat. 
Nos. 231,078, 231,079, 239,079 and 320,711 to the present inventor 
disclose such types of combination locks. In order to unlock such a 
conventional lock, the user must angularly move ring dials so as to 
arrange a series of numerical figures in a line on the peripheral surface 
of the dials at a predetermined dial setting position. This dial setting 
operation for unlocking is not only troublesome due to the fact that such 
conventional combination locks have four or more setting dials for the 
purpose of increasing the number of possible combinations, but also 
difficult or impossible in dark places or at night. Therefore, the user is 
apt to lock his combination lock by turning only one or two ring dials, 
above all when he is in a hurry, which may result in a possible theft. 
The present inventor has proposed in U.S. Pat. No. 4,445,348 issued May 1, 
1984, cylinder type combination lock in which the dial combination for 
unlocking can freely be set or changed by the user. According to such a 
combination lock, the user may set a desired dial combination, for 
instance numbers corresponding to his birthday, telephone number, house 
number or the like so that he will not forget the unlocking dial 
combination. However, this combination lock is disadvantageous in that it 
is not suitable to carry out its unlocking operation in dark situations 
and that the structure is relatively complicated thereby increasing its 
manufacturing cost. 
SUMMARY OF THE INVENTION 
Accordingly, a principal object of the present invention is to provide a 
cylinder type combination lock which can be locked or unlocked without 
necessity of reading a code on each dial. 
Another object of the invention is to provide a cylinder type combination 
lock which can be locked or unlocked without necessity of reading a code 
on each dial and which allows the user to select its unlocking dial 
combination. 
A further object of the invention is to provide a cylinder type combination 
lock which is simple in structure and has a minimum number of structural 
parts to reduce costs thereof while providing reliability. 
The cylinder type combination lock according to the invention comprises a 
first body of a substantially cylindrical configuration having an 
elongated hollow chamber therein, a plurality of windows formed in a row 
along a longitudinal direction and a key bore open at one end thereof, the 
first member being connected at the other end thereof with one end of a 
loop member such as chain or wire cable; a plurality of disk dials 
accommodated in the hollow chamber of the first body and each having an 
operation level projecting through the respective window; elastic means 
accommodated in the hollow chamber for urging and stably holding each of 
the dials to be angularly moved; and a second body connected with the 
other end of the loop member and having a key-like projection to be 
inserted into the first body through the key bore open at the free end 
thereof and by each slit formed in each of the dials. 
It is preferable that the first body has an elliptical shape in its cross 
section and that it is formed with two elongated structural pieces which 
may be formed by die casting and assembled with use of a suitable securing 
element such as a fixing pin. In this case, the first and second pieces 
are adapted to accommodate the dials and elastic means, respectively. 
The elastic means may comprise separate leaf springs each pressing a dial 
in the chamber of the first body to hold the dial in position, but it is 
preferable that the leaf springs have a common base so as to make setting 
thereof easy. Each leaf spring has a projection which engages into one of 
several grooves formed in a peripheral surface of the dial to allow a 
stepwise click rotation of the latter. The rotational angle of each dial 
is restricted by the degree of opening of the window formed in the first 
body, since the operation lever for the dial projects through the window 
when the combination lock is assembled. 
Each dial has a slit for forming the key bore which opens to the free end 
of the first body, so that the key-like projection of the second body can 
be inserted in or retracted from the chamber of the second body when the 
slits formed in each dial align with one another and with the slit formed 
at the free end of the first body. This state of the combination lock 
shall be referred to hereinafter as the "unlocking state". 
If the key-like projection of the second body is inserted through the key 
bore in the first body which is kept in the unlocking state and then at 
least one of the dials is rotated by actuating its operation lever by at 
least one step, a side wall of the angularly moved dial engages with a 
concerned tooth of the key-like projection to prevent retraction of the 
second body from the first one. This state of the combination lock shall 
be referred to hereinafter as "locking state". 
The slit of each dial is formed therein at a certain angle relative to the 
longitudinal axis of the lever for operating the dial. The angular 
arrangement of the slit formed in a specified dial determines the position 
of the dial operation lever within the window which is formed in the first 
body and through which the operation lever projects. The projection of the 
concerned leaf spring engages with a specified one of grooves formed in 
the peripheral surface of the dial to cause the alignment of the dial slit 
with the key bore opening in the end wall of the first body. In other 
words, the variety of the angular arrangement of the dial slits for the 
key bore depends on the number of the grooves formed in the peripheral 
surface of the dial. If each dial has three peripheral grooves so as to 
provide three angular positions of the operation lever within the window 
formed in the first body and each combination lock has four or more of 
such dials, a manufacturer may provide two or three dials with different 
slit angular positions and select a specific dial combination for 
unlocking from a plurality of possible dial combinations. In this case, 
the user who purchases the combination lock can set the dial combination 
for unlocking in accordance with information thereof provided on a tag 
attached to the lock, so that he can easily remember the set combination 
although it is given not as a numeral code but rather as angular positions 
of the levers for operating the dials. 
The parts for the combination lock according to the invention are less in 
number and kind. They include a first body which may be of two pieces 
joined by a securing means such as a fixing pin, a second body which has 
been previously connected to the first body through the loop member, and a 
plurality of dials each having an operation lever as well as an elastic 
means such as a combined leaf spring. Assembly thereof into the lock is 
quite easy. Therefore, the manufacturer may sell the combination lock in 
the form of kit therefor so that the user may select one of a large number 
of possible unlocking dial combinations to assemble his own lock.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings and more particularly to FIG. 1, a cylinder type 
combination lock according to the present invention comprises mainly a 
first body 10 and a second body 20. The first body 10 comprises a hollow 
cylindrical housing 101 formed with a plurality of windows 101a in a row 
along a longitudinal direction thereof and a slit 101b forming a key bore 
in one end wall thereof, and a head 102 fixed integrally with the other 
end wall of the housing 101, the head being connected with one end of a 
loop member 30 such as a wire cable, chain or the like. The second body 20 
has a key-like portion 201 and a head portion 202 integrally fixed with 
each other, the latter being connected with the other end of the loop 
member 30 so that when the key portion 201 is inserted in the first body 
through the slit 101b for locking, the closed loop is formed. Members 
generally designated by reference numeral 40 in FIG. 1 are operation 
levers each being integrally attached on the peripheral surface of a dial 
accommodated in the housing 101 of the first body 10. In the illustrated 
embodiment, the combination lock has five dial operation levers 40. The 
number of the levers and consequently of dials may be varied, but it is 
preferable to select four to six in since a larger number increases the 
number of possible dial combinations so as to more effectively prevent 
theft but makes the setting thereof into its specific dial combination 
troublesome. Even if six is selected it will be appreciated that the 
locking and unlocking operation by the actuating levers is far easier than 
angularly moving for instance four ring dials each having numerical 
figures 0-9 around the surface to form a predetermined four numerical 
figures arrangement. 
As shown in FIG. 2, each disk dial 50 fixed with lever 401 is accommodated 
in the housing 101 of the first body 10 so that the lever 401 projects 
through the concerned window 101a. The dial 50 has a plurality of grooves 
501 formed in its peripheral surface and a central slit 502 for the key 
bore. The dial 50 is urged in the housing 101 by an elastic means such as 
a leaf spring 60 having a projection 601 so as to engage with any of the 
grooves 501, whereby operation of the lever 401 causes a stepwise click 
rotation of the dial 50 in the housing. Due to the rotation of the dial 
50, the central slit 502 formed in the dial 50 changes in its angular 
position to cause an alignment or non-alignment thereof to one another and 
with the key bore (FIG. 1) open at the free end of the housing 101, which 
correspond to an "unlocking position" and "locking position", 
respectively. 
In the illustrated embodiment, each of the dials 50 has three peripheral 
grooves 501 and thus the operation lever 401 can take one of the three 
angular positions within the window 101a. Two of such positions are shown 
in FIG. 2 in solid and broken lines, respectively, but the number of the 
angular positions for the lever 401 may be increased or decreased. 
As shown in FIG. 3, the first body 10 may be made from two separate 
elongated structure pieces, namely a first or main piece 10a accommodating 
mainly the dials 50 and a second or lid like piece 10b accommodating 
mainly leaf springs 60. The first and second pieces may integratedly be 
assembled by securing means such as a fixing pin 101g to be inserted 
through a through-hole 101c formed in each end wall of the first piece 10a 
and in a blind-hole 101d formed in each end wall of the second piece 10b. 
Owing to such construction, the two pieces may be formed according by die 
casting at a low cost and the dials 50 and elastic means may readily be 
assembled in the housing 101. It is preferable that the first piece 10a 
has a plurality of libs 101e on inner surface thereof to stably 
accommodate each dial 50 between neighboring two libs and that the second 
piece 10b has shoulders 101f with a curved surface which serve as a seat 
for each of the dials 50. 
The leaf springs 60 accommodated in the second piece 10b may consist of 
individual springs for each dial 50, but it is preferable to manufacture 
the springs with a common base plate as shown in FIG. 4. The elastic means 
shown in FIG. 4 comprises a common base 60a of a metallic material with 
each leaf spring 60b being formed integrally with the base 60a. Such an 
elastic means is preferable in that the entire elastic means with a 
plurality of leaf springs can be manufactured through a single stamping 
operation of a metallic material sheet and a bending operation common to 
the leaf springs to be formed. Also it is quite easy to assemble the 
elastic means into the second piece. 
In FIGS. 5(A) and 5(B), there are shown dials 50a and 50b which are 
different from the dial 50 as shown in FIG. 2 in that in FIG. 2 the 
central slit 502 forming the key bore is extended perpendicular to the 
axis of the dial operation lever 401. On the other hand, each of the dials 
50a and 50b in FIGS. 5(A) and 5(B) has, respectively, a central slit 502a 
(502b) arranged not at a right angle to the longitudinal axis of the dial 
operation lever 401a (401b), but rather slanted at some other angle. If 
all of the dials for each combination lock were the same, there would be 
only one common unlocking dial combination for the lock and thus such lock 
could not be a "combination lock". Therefore, the dials each formed with 
the central slit in various angular arrangements relative to the axis of 
its operation lever, namely the dials 50, 50a and 50b should be provided 
and those are employed in combination for each combination lock having an 
inherent unlocking dial combination selected from a large number of 
possible combinations. 
In the illustrated embodiment, the dials are selected from three kinds, 
namely dials 50, 50a and 50b but it is to be noted that a number of the 
dial kinds may be increased or decreased depending on the number of 
grooves to be formed in the peripheral surface of the dial. 
The invention will now be further explained as to how to set a desired 
unlocking dial combination and assemble the combination lock. 
The manufacturer or user inserts the leaf spring assembly 60 in the second 
piece 10b 10 so that the base 60a of the assembly 60 is disposed on a flat 
bottom in the second piece 10b. In the case of the illustrated combination 
lock with five dials to be selected from three kinds of dials (50, 50a and 
50b), he then selects five dials among the three kinds to provide a 
desired dial operation lever arrangement for unlocking and inserts them in 
the first piece 10a to attain the lever arrangement, wherein all key slits 
(502, 502a and 502b) of the dials aligns with one another and with the 
slit 101b for the key bore at the end wall of the first piece 10a or 
housing 101. Thereafter, he applies the second piece 10b accommodating the 
leaf spring assembly 60 on the first piece 10a accommodating the dials in 
order and inserts the fixing pin or the like element in the holes 101c and 
101d to fit the same therein to assemble the combination lock. This 
combination lock is now in the unlocking state to allow insertion of the 
second body 20 having key-like projection 201 as shown in FIG. 1 into the 
first body 10 through the key bore 101b opening in the end wall of the 
first body 10 and formed by the slits in the dials. If at least one of the 
dial operation levers 401, 401a and 401b is actuated to cause angular 
movement of the concerned dial when the key-like projection 201 of the 
second body 20 has been fully inserted in the first body 10, such rotation 
of the dial causes non-alignment of its slits 502, 502a, or 502b with the 
slit 101b formed in the end wall of the first body 20 to prevent 
withdrawal of the second body 20 from the first body 10, namely the 
combination lock is then in its locking state. 
According to the combination lock of the invention, the specific or 
inherent unlocking dial combination thereof can be memorized not as 
numeral figures or the like code but as a positional combination of the 
dial operation levers and thus the user may operate his combination lock 
for locking or unlocking, even in a darkened situation without relying on 
a code as is conventionally used dials but depending on feeling with his 
finger.