Combination lock

An easily assembled combination lock has improved tumbler wheel construction, combination changing apparatus, and a bi-positional lock cover which selects between spring-bolt and dead-bolt operation. The improved tumbler wheels have two-piece construction, an inner drive member having a projection, groove and stop assembly cooperating with adjacent tumbler wheels, and a gate ring having a gate and improved gripping apparatus for frictionally engaging the gate ring with the inner drive member. The inner drive member has multiple ratchet teeth about its periphery and the improved gripping apparatus includes a pair of diametrically opposed gripping straps integral with the gate ring, in tension, and tangentially contacting the periphery of the inner drive member imparting a predetermined frictional resistance to rotation. Two normal modes of tumbler wheel operation are contemplated. Mode selecting structure is included on the lock cover to select between spring-bolt mode of bolt operation and dead-bolt mode of bolt operation merely by changing the orientation of the lock cover relative to the lock mechanism and housing.

This invention relates generally to combination locks and, more 
specifically, to locks which are easily assembled, have a changeable 
combination, and may be selectively operated in more than one mode. 
BACKGROUND OF THE INVENTION 
Lock mechanisms are generally used to maintain the door of an enclosure in 
a closed condition thereby securing the enclosure from unwanted entry and 
the contents of the enclosure from theft. These mechanisms usually have a 
bolt structure carried by the door which engages a latch or recess of the 
door frame portion of the enclosure to maintain the door in a closed and 
locked position. The bolt structure is selectively moveable out of 
engagement with the latch recess by a pre-determined manipulation of the 
lock mechanism. This manipulation may be the insertion and rotation of a 
specially configured key, or may be the pre-determined sequence of 
rotations of a combination dial. 
These enclosures may be safes, storage rooms, vehicles, homes, or offices. 
Depending on the type of enclosure, one of two common modes of bolt 
operation is employed. One of these modes is known as dead-bolt operation 
in which the bolt structure is moved between locked and unlocked positions 
only by manipulation of the lock mechanism. In this mode, in order to 
engage the bolt with the latch recess thereby locking the door of an 
enclosure, a positive manipulation of the lock mechanism is required. 
The other common mode of bolt operation is spring-bolt operation wherein 
the bolt is biased to the locked position by a spring and the bolt is 
configured with a slanted ramp surface by which motion of the door from 
the open to the closed position results in automatic locking of the door. 
Specifically, the motion of the door causes the frame of the door or 
enclosure to engage the slanted surface of the bolt overcoming the bias of 
the spring and causing the bolt to be retracted from the locked to the 
unlocked position. Further motion allows the bolt to be aligned with the 
recess, releasing the bolt to the locked position under the urging of the 
spring such that the bolt automatically extends into the recess or latch 
of the door frame. Spring-lock operation permits locking of the door as it 
closes without requiring positive manipulation of the lock mechanism. 
In the particular application of doors for houses, lock mechanisms have 
been manufactured to function by each of the described modes of bolt 
operation. Once a lock having one of the modes of operation was installed 
in a door, however, it was necessary to completely replace the lock 
mechanism in order to change the mode of bolt operation. Since it is very 
rare for two different lock mechanisms to utilize the same mounting holes 
or bolt locations, it is usually an expensive and destructive process to 
change the lock mechanism of a door in order to change the mode of bolt 
operation. 
One common lock mechanism is the combination lock wherein the exterior 
surface of the door has a circular rotatable dial with numeric indicia 
about its periphery and a stationary marker proximate the dial as a 
reference point. This type of lock mechanism is operated by manipulation 
of the dial in a pre-determined sequence of alternating clockwise and 
counter-clockwise rotations aligning specified numeric indicia with the 
marker. The specified sequence of manipulations permits the bolt to be 
moved to the unlocked position by either a further manipulation of the 
dial or a manipulation of a separate lever or handle. A mechanism utilized 
to accomplish this function is exemplified by U.S. Pat. No. 4,142,388 
entitled "Tumbler Wheels for Combination Locks", issued to Peter J. 
Phillips on Mar. 6, 1979. 
Combination lock mechanisms typically include a number of rotatable tumbler 
wheels, each wheel having a gate member positioned at one point about its 
periphery for receiving and cooperating with a pawl. Each of the tumbler 
wheels further includes a projection on one side and an annular groove 
with a stop on the other side. The projection of one wheel cooperates with 
a groove-and-stop assembly of an adjacent tumbler wheel whereby a 
particular tumbler wheel may rotate a portion of a full revolution 
independently of the adjacent wheel and then the projection engages the 
stop contained within the groove causing simultaneous subsequent rotation 
of the adjacent tumbler wheel. 
The stop, groove and projection, and the gate means have a pre-determined 
angular orientation which dictates one of the rotational manipulations 
required of the combination lock dial. The proper sequence of 
manipulations causes the gate means of each of the multiple tumbler wheels 
to become aligned such that a single pawl member may rotate radially 
inward with respect to the multiple tumbler wheels into the gate members. 
This alignment of the gate means and resulting motion of the pawl places 
the lock in a condiiton which permits unlocking motion of the bolt by a 
further manipulation of the lock mechanism. 
It is also commonly known for combination locks to have a changeable 
combination. Once each of the gate means of the tumbler wheels has been 
aligned as just described, a keyway portion of each tumbler wheel is 
similarly aligned and may receive a specially configured key. For the 
combination lock to have a changeable combination, it is necessary that 
the tumbler wheels have a multi-part construction such that the angular 
orientation of the stop and projection relative to the gate means may be 
changed. Typical tumbler wheels are comprised of an outer gate ring, 
including a gate for cooperation with a pawl, an inner drive ring with a 
projection, stop and groove assembly, and a cam, securing or locking 
mechanism for causing the outer gate ring and the inner drive ring to 
rotate in a unitary manner. 
Prior tumbler wheels had extensive multi-part locking devices for securing 
the gate ring to the inner drive ring preventing inadvertent rotation of 
the gate formed as part of the gate ring relative to the inner drive ring 
having the projection, groove and stop. These locking devices are 
expensive to manufacture, are complex to assemble, may be unreliable, and 
required a specially configured key and complex series of key 
manipulations in order to change the lock combination. 
SUMMARY OF THE PRESENT INVENTION 
Accordingly, it is a primary object of the present invention to disclose 
and provide a combination lock that overcomes these disadvantages. More 
particularly, the objects of the present invention include disclosing and 
providing a combination lock that: has a mechanism adapted to utilize 
either a spring-bolt configuration or a dead-bolt configuration and 
function consistently therewith; has all parts interchangeable with either 
a spring-bolt or a dead-bolt; has a lock mechanism which may be switched 
between spring-bolt and dead-bolt modes of bolt operation merely by 
changing the orientation of the lock cover; is simply, easily and 
inexpensively assembled; is formed of simply designed parts not requiring 
expensive materials; has tumbler wheels with only two-piece snap-together 
construction; has a changeable combination, said combination being easily 
changed by a simple rod-shaped pin which may be inserted in any rotational 
orientation into the lock mechanism; has a highly reliable means for 
imparting a predetermined frictional resistance to rotation of the gate 
ring relative to the inner drive member; and has a variable length 
break-away shaft for ease of mounting to any thickness of door. 
Briefly, the present invention comprises an easily assembled combination 
lock having improved tumbler wheel construction, combination changing 
apparatus, and a bi-positional lock cover which selects between 
spring-bolt and dead-bolt operation. According to one feature of the 
invention, the improved tumbler wheels have two-piece construction, an 
inner drive member having a projection, groove and stop assembly 
cooperating with adjacent tumbler wheels, and a gate ring having a gate 
and improved gripping apparatus for frictionally engaging the gate ring 
with the inner drive member. The inner drive member has multiple ratchet 
teeth about its periphery and the improved gripping apparatus includes a 
pair of diametrically opposed gripping straps integral with the gate ring, 
in tension, and tangentially contacting the periphery of the inner drive 
member imparting a predetermined frictional resistance to rotation. 
Two normal modes of tumbler wheel operation are contemplated. In 
combination-dialing mode the inner drive member and the gate ring rotate 
in a unitary manner in response to the gripping apparatus, preserving the 
rotational orientation of the gate relative to the groove, stop and 
projection which is determinant of the lock combination. In 
combination-changing mode the inner drive member rotates relative to the 
gate ring to change their relative orientation and thereby change the 
combination. 
In accordance with the combination changing feature of the invention, a rod 
shaped pin is simply inserted in any rotational orientation through 
apertures in the gate rings causing the rings to be held stationary and 
the frictional resistance to rotation to be overcome, thereby permitting 
rotation of the inner drive member relative to the gate ring changing 
their relative rotational orientation and thereby changing the lock 
combination. 
Each member in tension or strap of the gripping means can be easily 
manufactured by forming a semi-circular cutout in the gate ring proximate 
its central bore. Said cutout leaves an elongated strap integral with the 
gate ring extending between two angularly displaced anchor points at the 
ends of the cutout. Insertion of the inner drive member into the bore of 
the gate ring stretches the strap about the member's periphery thereby 
placing the strap in tension. This tension causes a predetermined 
frictional resistance to rotation therebetween at the point of tangential 
contact. Contact teeth on the strap at that point of contact engage with 
ratchet teeth on the periphery of the inner drive member to cause relative 
rotation to occur in a ratcheting manner and the inner drive member to be 
capable of having only a finite number of rotational orientations relative 
to the gate ring and corresponding to integer number positions of the 
combination lock dial. 
In accordance with another feature of the present invention, an identity of 
lock mechanism parts may be used with either a spring-bolt configuration 
or a dead-bolt configuration of bolt. Mode selecting structure is included 
on the lock cover to select between spring-bolt mode of bolt operation and 
dead-bolt mode of bolt operation merely by changing the orientation of the 
lock cover relative to the lock mechanism and housing. More specifically, 
a cam-like surface is contained on one portion of the lock cover for 
engaging the pawl of the lock mechanism to prevent unlocking motion of the 
bolt without proper manipulation of the lock dial whenever the lock cover 
is mounted in an orientation associated with dead-bolt mode of bolt 
operation. Mounting the lock cover in the other orientation, associated 
with spring-bolt mode of bolt operation, allows unrestricted motion of the 
bolt in the unlocking direction whenever a force on the bolt in the 
unlocking direction overcomes the biasing of the bolt spring in the 
locking direction, such as when the ramp surface of a spring-bolt 
configuration of bolt encounters the latch surface of a door frame or 
enclosure as during closing of the door. 
All of the foregoing is accomplished with simple uniform parts that are 
interchangeable with either a spring-bolt configuration or dead-bolt 
configuration of bolt and which are simply manufactured of inexpensive 
materials and which principally snap together or drop into the lock 
housing permiting rapid, simplified, and inexpensive assembly. 
The present invention can be more fully understood by one skilled in the 
art and additional advantages and features can be recognized from a 
consideration of a detailed description of a preferred exemplary 
embodiment of the invention, and drawings thereof, as foolows:

DETAILED DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT: 
FIGS. 1-12 show a preferred exemplary embodiment of a lock utilizing the 
improvements of the present inventiond. Referring initially to FIG. 11, 
the preferred embodiment comprises a combination lock including a lock 
mechanism 30 encased within a lock housing 10 and a mating lock cover 20. 
More specifically, lock housing 10 has single piece construction and is 
formed with a base portion 11 and four sidewall portions 12. One of those 
sidewall portions 13 includes a rectangular U-shaped cutout 16 for forming 
a bolt aperture when lock housing 10 is combined with lock cover 20 as 
particularly shown in FIGS. 1, 2, 6, and 9. 
Referring to FIG. 1, lock housing 10 further includes a jounal sleeve 17 
projecting upwardly from base 11 and disposed centrally within the lock 
housing 10. Journal sleeve 17 has a cylindrical bore 18 extending 
therethrough and adapted to receive a driver 70 as will be later 
described. Journal sleeve 17 is further provided with a substantially 
cylindrical exterior surface 79 which, in addition to bore 18, serves as a 
journal surface and about which multiple tumbler wheels 60 may be mounted 
and rotated as will be later described. The exterior surface 79 of the 
journal sleeve 17 is provided with two diametrically opposed aligning 
grooves 78 for cooperation with guides 39 of multiple spacers 38 which 
will be later described. The portion of the exterior surface 79 of journal 
sleeve 17 proximate the base 11 is further provided with a cylindrical 
collar 19 having a diameter greater than the external diameter of journal 
sleeve 17 and serving as a support for the first of multiple tumbler 
wheels 60 mounted thereon as, again, will be described in more detail. 
A pair of mounting apertures 15 are provided in opposing corners of lock 
housing 10 for receiving fastening means, particularly mounting screws 24 
for mounting lock cover 20 to the lock housing 10. Said mounting apertures 
15, particularly shown in FIG. 2, may be cast in the lock housing 10 and 
adapted to receive self-tapping machine screws as are known in the art. 
Lock cover 20 is adapted to mate with lock housing 10 to form an enclosure 
having an internal chamber substantially the shape of a rectangular solid. 
FIGS. 6 and 9 show lock cover 20 attached to lock housing 10 by fastening 
means, particularly machine screws 24 extending through mounting apertures 
21 of lock cover 20 and into mounting apertures 15 of lock housing 10. The 
mounting apertures 21 and 15 of the lock cover and lock housing are 
arranged such that the lock cover may be mounted with respect to the lock 
housing in more than one orientation. FIG. 6 shows the lock cover 20 
mounted to the lock housing 10 in a first orientation and FIG. 9 shows the 
same lock cover 20 mounted to the same lock housing 10 in a second 
orientation in which lock cover 20 has been rotated 180 degrees. 
Referring to FIGS. 6, 9, and 10, lock cover 20 is further provided with 
mode selecting means 27. Mode selecting means 27 includes the provision of 
spring bolt indicia 22 and dead bolt indicia 23 on the exterior surface of 
lock cover 20 and the provision of mode selecting structure 28 on the 
interior surface of lock cover 20 as particularly shown in FIG. 10. Mode 
selecting structure 28 may selectively engage lock mechanism 30 in a 
manner which will be later described, said engagement being determined by 
the orientation of the lock cover 20 relative to the lock housing 10 and 
identified by the proximity of either the spring bolt indicia 22 or the 
dead bolt indicia 23 with the bolt means 40 extending through bolt 
aperture 16 in lock housing 10. 
The combined structure of the lock, including lock mechanism 30 having bolt 
means 40, contained within lock housing 10 and lock cover 20, may be 
mounted to the door of an enclosure to maintain the door of the enclosure 
in a closed and locked position thereby securing the contents of the 
enclosure from theft and preventing unwanted entry into the enclosure. In 
order to accomplish this function, the assembled lock as shown in FIGS. 6 
and 9 is mounted to the interior surface of the door proximate an edge 
thereof such that the bolt means 40 may extend beyond the edge of the door 
to engage a latch or recess carried by the door frame of the enclosure 
whenever the door is in a closed and locked condition. A pair of mounting 
flanges integral with housing 10 and having apertures 77 is shown in FIG. 
6 and facilitates the mounting of the lock mechanism to the interior 
surface of the door using mounting screws 36 as shown in FIG. 11. 
The particular type of lock mechanism contained within the lock housing 10 
in this preferred exemplary embodiment is a combination lock mechanism 30. 
Accordingly, the door of the enclosure is further provided on its exterior 
surface with a face plate 33 and a combination lock dial 31 containing 
numeric indicia 32 alignable with a reference point appearing on face 
plate 33. A shaft 34 attached to dial 31 extends through the door into the 
bore 18 of journal sleeve 17 wherein it is operably connected to driver 
70. As shown in FIG. 11, shaft 34 is provided with break-away portions of 
its extended length such that the shaft 34 may be easily adjusted for 
various door widths which it must penetrate and still leave sufficient 
shaft length having keyway grooves 35 to operably connect with the keyway 
guide 72 of driver 70. Mounting screws 36 extend from face plate 33 on the 
exterior surface of the door through the door and through the mounting 
flange apertures 77 on the interior surface of the door at which point 
mounting nuts 37 secure the combined face plate 33, combination lock dial 
31, and lock mechanism 30 contained within lock housing 10 to the door of 
the enclosure such that bolt means 40 extends beyond the edge of the door 
to engage the door frame of the enclosure. 
The combination lock mechanism 30 of the present invention particularly 
includes bolt means 40 having two alternative configurations and 
permitting two alternative modes of bolt operation. Two bolt 
configurations are contemplated for use with the present invention, a 
spring-bolt configuration 41 and a dead-bolt configuration 43. Either of 
these bolt configurations is generally referred to as bolt means 40. The 
bolt means is formed of a solid structure contained within lock housing 10 
and movable such that a bolt portion may selectively translate into and 
out of bolt aperture 16 to selectively protrude external of the lock 
housing and engage the door frame of the enclosure. A bolt spring 45 is 
provided for biasing the bolt means 40 to cause the bolt portion to extend 
outward of the lock housing 10 such that it moves from the position shown 
in FIG. 3 to the position shown in FIG. 2, engaging the door frame of the 
enclosure. Specifically, bolt spring 45, as particularly shown in FIG. 2, 
is mounted between the spring biased surface 46 of the bolt structure and 
the corresponding spring biased surface 14 of the lock housing. Referring 
to FIG. 5, the bolt structure further includes spring channel walls 47 
having the shape of a rectangular solid when in cooperation with a 
sidewall 12 and edge of the base 11 of the lock housing to form a 
longitudinally elongated chamber for containing the bolt spring 45 in an 
operative condition. 
The dead-bolt configuration 43 of bolt means 40 specifically contemplates 
that the portion of the bolt structure extending outwardly of the lock 
housing through bolt aperture 16 has the shape of a rectangular solid 
which engages the door frame of the enclosure in a manner which most 
securely prevents unwanted entry into the enclosure. 
The spring-bolt configuration 41 of bolt means 40 is similar to the 
dead-bolt configuration 43 with the additional provision of a ramp surface 
42 angularly disposed with respect to the otherwise rectangular solid 
surface of the protruding portion of the bolt extending beyond bolt 
aperture 16. Ramp surface 42 is inclined at an acute angle with respect to 
the axis of translational motion of the bolt, protracting and retracting 
with respect to the lock housing 10. In this manner, ramp surface 42 may 
cooperate with a latch surface of the door frame of the enclosure to 
translate motion of the door in a closing direction into motion of the 
bolt means 40 into a retractive direction into the lock housing 10 until 
such time as the ramp surface 42 has passed over an outward extending 
portion of the latch surface of the door frame and is no longer in 
occlusion therewith such that, in response to bolt spring 45, the bolt 
means 40 may once again protract outward of the lock housing 10 and into 
engagement with the door frame thereby maintaining the door in a locked 
condition. This spring-bolt configuration 41 permits locking of the door 
of the enclosure in an automatic manner simply by closing the door. On the 
other hand, the dead-bolt configuration 43 requires a positive 
manipulation of the lock mechanism to translate the bolt from the unlocked 
to the locked position. 
Accordingly, the lock mechanism 30 may be selectively operated in two 
alternative normal modes of bolt operation. The selection of the mode of 
bolt operation is accomplished by the rotational orientation of the lock 
cover 20 with respect to lock housing 10. The first mode of bolt operation 
is referred to as dead-bolt mode and is typically associated with the use 
of a dead-bolt configuration 43 of bolt means 40. The second mode of bolt 
operation is referred to as spring-bolt mode and is typically associated 
with the use of a spring-bolt configuration 41 of bolt means 40. The 
matching of the bolt configuration with the mode of bolt operation is not 
required by the present invention and thus a spring-bolt configuration 41 
may be used with a dead-bolt mode of bolt operation and a dead-bolt 
configuration 43 may be used with a spring-bolt mode of bolt operation. 
These combinations are in addition to the contemplated combinations of a 
spring-bolt configuration 41 with a spring-bolt mode of bolt operation and 
a dead-bolt configuration 43 with a dead-bolt mode of bolt operation. 
Essentially, the dead-bolt mode of bolt operation permits motion of the 
bolt means 40 from the locked position to the unlocked position only when 
the proper combination has been dialed. The spring-bolt mode of bolt 
operation permits motion of the bolt means 40 from the locked to the 
unlocked position either when the proper combination has been dialed or 
when a retracting force is applied to the bolt itself overcoming bolt 
spring 45 such as when ramp surface 42 engages the door latch surface 
during closing of the door. 
Bolt means 40 is further provided with pawl post 48 having a cylindrical 
shape and adapted to receive and mount pawl 50. Additionally, bolt means 
40 is provided with pawl spring stop 49, as particularly shown in FIG. 10, 
for anchoring one end of pawl spring 51 as will be further described. 
Pawl 50 is provided as particularly shown in FIGS. 2, 3, 10, and 11. Pawl 
50 is particularly adapted for mounting upon pawl post 48, such that the 
pawl may rotate about the post such that a tumbler wheel engaging portion 
of the pawl may rotate radially inward and outward with respect to the 
multiple tumbler wheels 60 to engage the respective gate means 85. 
Accordingly, pawl 50 is provided with a cylindrical bore 53 for sliding 
over and rotating about pawl post 48 and is further provided with a pawl 
spring stop 52 which, as shown in FIG. 11, has the shape of a pin. 
Pawl spring 51 is provided for mounting about pawl post 48 and engaging the 
pawl spring stop 49 of bolt means 40 and the pawl spring stop 52 of pawl 
50 for rotationally biasing the pawl 50 relative to pawl post 48. 
More specifically, pawl 50 is comprised of an arm 54 having a cylindrical 
bore 53 at one end which is adapted to receive pawl post 48, and a head 55 
at the other end. Head 55 has two portions which are alignable with the 
rotational portions of the lock mechanism to permit unlocking of the bolt 
means 40. The first portion is the tumbler wheel engaging surface 56 
which, in the preferred embodiment, is a longitudinally elongated cam 
follower type surface which contacts the periphery of each of the three 
tumbler wheels 60. The second portion of pawl head 55 is driver engaging 
surface 57 which is similarly a cam follower type of surface for engaging 
the periphery of driver 70. Driver 70, as will be more fully described, 
includes cutout 74 similar to the gate means 85 which, when not in 
alignment with the driver engaging surface 57 of pawl 50, prevents the 
pawl from rotating radially inward with respect to the multiple tumbler 
wheels 60. The assembled pawl 50, pawl spring 51, and bolt means 40 is 
shown in FIG. 10. Pawl spring 51 is a coil spring adapted to bias pawl 50 
such that the outward extension of the pawl head 55, rotates radially 
inward with respect to the multiple tumbler wheels 60. In response to the 
biasing of pawl spring 51, pawl 50 may move from the ghosted position of 
FIG. 4 to the solid position of FIG. 4 whenever the gate means 85 of each 
of the multiple tumbler wheels 60 and the driver 70 are mutually aligned. 
Accordingly, misalignment of the gate means 85 of any one of the three 
tumbler wheels 60 or the driver 70 maintains pawl 50 in its radially 
outward position particularly shown in FIG. 2 which prevents the lock 
mechanism 30 from causing an unlocking motion of bolt means 40. 
Pawl 50 further includes a mode selecting structure engaging surface 58 for 
selectively engaging the pawl engaging surface 29 of mode selecting 
structure 28 contained on lock cover 20. The cooperation between the pawl 
50 and the mode selecting structure 28 contained on lock cover 20 is 
particularly shown in FIG. 3. The ghosted position of pawl 50 shown in 
FIG. 3 is associated with those times when the gate means 85 of any one of 
the multiple tumbler wheels 60 or the cutout 74 of the driver 70 is 
misaligned with the head 55 of pawl 50. When the lock cover 20 is oriented 
in the position associated with the dead-bolt mode of bolt operation, the 
mode selecting structure 28 is positioned as shown in FIG. 3 and the pawl 
engaging surface 29 of that structure may contact the mode selecting 
structure engaging surface 58 of head 55 of pawl 50 which prevents 
translational motion of the pawl from left to right which accompanies 
unlocking motion of bolt means 40, the direction shown by arrow 59 in FIG. 
3. In this configuration, an externally supplied force on the portion of 
the bolt means 40 protruding from lock housing 10 in the direction of 
arrow 59 is not capable of translating bolt means 40 from the locked 
position shown ghosted in FIG. 3, to the unlocked position, shown solid in 
FIG. 3. It is only when the proper combination has been dialed and the 
gate means 85 and cutout 74 are aligned that head 55 of pawl 50 may rotate 
radially inward into the gate means 85 and cutout 74 permitting the mode 
selecting structure engaging surface 58 to rotate out of engagement with 
the mode selecting structure 28 and thereby make the bolt means 40 capable 
of translating to the bolt unlocked position, shown solid in FIG. 3, in 
response to a further, clockwise in FIG. 3, manipulation of the lock dial 
31. 
During spring-bolt mode of bolt operation, the lock cover 20 is mounted in 
a reverse orientation such that the mode selecting structure 28 is in the 
position shown by FIG. 2, out of engagement with head 55 of pawl 50. In 
this mode of bolt operation, a force in the direction of arrow 59 on bolt 
means 40 may overcome the biasing of bolt spring 45 and cause the bolt 
means 40 to be translated from the locked position to the unlocked 
position, left to right as seen in FIG. 3. It is only when each of the 
gate means 85 of the multiple tumbler wheels 60 and the cutout 74 of 
driver 70 are aligned that the bolt means 40 may be translated from the 
locked position to the unlocked position by a further manipulation of the 
lock mechanism, specifically a further rotation of lock dial 31 in a 
clockwise direction as seen in FIG 3. 
Rotatably mounted about journal sleeve 17 are multiple tumbler wheels 60 
which may be interspaced by spacers 38 and a driver 70, as particularly 
shown in FIGS. 1-5 and 11. 
The improved multiple tumbler wheels 60 of the present invention have a 
two-part construction wherein means for provided for two normal modes of 
operation. The preferred embodiment includes three identical tumbler 
wheels 60 each having an inner drive member 61 and an outer ring or gate 
ring 80. The inner drive member 61 is substantially an annular ring having 
a cylindrical bore 62 of a size sufficient that the inner drive member 61 
may be mounted about the external surface 79 of journal sleeve 17 and 
freely rotatable with respect thereto. The annular ring of inner drive 
member 61 has a first side 63 shown in FIG. 7 and a second side 64 shown 
in FIG. 8. First side 63 is provided with an eccentrically located 
projection 67 which protrudes perpendicularly from the first side 63 of 
inner drive member 61. The second side 64 of inner drive member 61 
includes an annular groove 65 of a size and depth sufficient to receive 
the projection 67 of an adjacently mounted inner drive member 61 such that 
when one of the inner drive members rotates with respect to the other one, 
the projection 67 on the first side 63 of the first inner drive member 
rotates in the circular path provided by groove 65 on the second side 64 
of the second, adjacent inner drive member. Groove 65 is provided with a 
stop 66 which may engage a projection 67 of an adjacent inner drive member 
as it travels in groove 65 to cause the two inner drive members to rotate 
in unison subsequent to one of the two inner drive members rotating less 
than a full revolution independent of the other inner drive member. This 
function is illustrative of the first of two normal modes of contemplated 
operation of the three tumbler wheels of the preferred embodiment. Said 
mode is referred to as a combination dialing mode and in this mode, the 
inner drive member 61 of each tumbler wheel 60 may rotate independently of 
adjacently mounted inner drive members 61 for less than a full rotation in 
any one direction until such time as a further rotation causes the 
projection 67 of one of the inner drive members 61 to rotate within groove 
65 into contact with stop 66 of the adjacent inner drive member 61. 
Inner drive member 61 is further defined by a peripheral edge 68. 
Peripheral edge 68 further includes an annular groove 69 proximate the 
first side 63 of the inner drive member 61. As best seen in FIGS. 1 and 
11, groove 69 is particularly configured to mate with ridge 82 of outer 
ring 80, as will be more fully described. Additionally, peripheral edge 68 
is provided with ratchet teeth 98 extending about the periphery of inner 
drive member 61 proximate its second side 64. These ratchet teeth 98 
cooperate with gripping means 90 of outer ring 80 in a manner which will 
be more fully described. 
The second part of each of the multiple tumbler wheels 60 is outer ring or 
gate ring 80. Outer ring 80 has an inner bore 81 having a ridge 82 
extending about its interior and adapted such that the bore 81 of outer 
ring 80 may be mounted about the peripheral edge 68 of inner drive member 
61. Ridge 82 within bore 81 fits into groove 69 on peripheral edge 68 and 
cooperates to prevent axial translation of outer ring 80 relative to inner 
drive member 61. This groove and ridge construction permits outer ring 80 
to have only rotational motion relative to inner drive member 61. In this 
manner, outer ring 80 may be snapped onto the periphery of inner drive 
member 61 to form multiple tumbler wheels 60 as shown in FIGS. 7 and 8. 
Outer ring 80 has a periphery 83, numeric indicia 84 positioned on one side 
of outer ring 80 proximate its periphery 83, and includes gate means 85 
located at one point on the periphery of outer ring 80. Gate means 85 is 
operably formed of a cutout 86 from the peripheral edge 83 of outer ring 
80. The periphery 83 with gate means 85 together act as a cam surface 
which cooperates with the tumbler wheel engaging surface 56 of pawl 50. 
Gate means 85 functions to permit the head 55 of pawl 50 to rotate about 
pawl post 48 radially inward with respect to the tumbler wheel whenever 
the gate means 85 is in alignment with the head 55 of pawl 50. Outer ring 
80 further includes orienting means 87 which, in the preferred embodiment, 
is comprised of a single orienting aperture 88 having a predetermined 
angular orientation relative to gate means 85 and positioned proximate 
periphery 83 of outer ring 80. Orienting aperture 88 has an axis eccentric 
to the axis of tumbler wheel 60 and is adapted to receive a combination 
changing pin 89 under predetermined conditions which will be more fully 
described. 
Gripping means 90 are included in outer ring 80 for cooperation with inner 
drive member 61. It is specifically contemplated by the present invention 
that gripping means 90 impart a predetermined resistance to relative 
rotation of outer ring 80 relative to inner drive member 61 and that when 
said predetermined resistance to relative rotation has been overcome, that 
relative rotation occurs in an integer or ratcheting manner such that 
outer ring 80 may have only a finite number of rotational positions 
relative to inner drive member 61. It is notable that indicia 84 may 
numerically identify said finite number of rotational orientations, or be 
a whole number multiple thereof, and may correspond with the numeric 
indicia 32 on combination lock dial 31. 
It is specifically contemplated that gripping means 90 impart a 
predetermined frictional resistance to rotation of outer ring 80 relative 
to inner drive member 61 in order to provide two normal modes of operation 
for the tumbler wheels 60. The first of said modes of operation is a 
combination-dialing mode wherein the two parts of each of the tumbler 
wheels 60 rotate in a unitary manner in response to the frictional 
resistance to rotation provided by gripping means 90. The second 
contemplated mode of operation is referred to as combination-changing mode 
wherein inner drive member 51 rotates independently of outer ring 80 
thereby altering the relative rotational orientation of the two parts. It 
is this relative rotational orientation, the rotational juxtaposition of 
stop 66 and projection 67 relative to cutout 86 of gate means 85 that 
determines one of the sequence of combination lock dial manipulations 
necessary to unlock the lock mechanism 30. 
In the preferred embodiment, gripping means 90 comprises a pair of 
diametrically opposed gripping straps, first strap 91 and second strap 92. 
Each of these gripping straps 91 and 92 is a member in tension 93, each 
tensioned between first and second angular positions 94 and 95 of outer 
ring 80. Each of the gripping straps 91 and 92 has a tangential contact 
point 96 which may include one or more contact teeth 97 for engaging the 
multiple ratchet teeth 98 on the periphery of inner drive member 61. It 
has been found that rather than using a cantilevered construction of 
resilient material, a more predictable and reliable resistive force is 
created by using a member in tension 93. Each of the members in tension 93 
may be easily manufactured in an outer ring 80 formed or cast of a 
resilient material by providing a cutout 99 in outer ring 80 centered 
about each of the diametrically opposed contact teeth 97 forming the first 
and second grip straps 91 and 92. It may be seen in FIG. 2, that this 
arcuate cutout 99 causes an inward portion of outer ring 80 to extend 
between first and second angular positions 94 and 95. When the outer ring 
80 is snapped onto the periphery of inner drive member 61 to form a 
tumbler wheel 60, the peripheral edge 68, having a diameter slightly 
larger than the unstressed circumference of bore 81, causes the contact 
teeth 97 at the tangential contact point 96 to be repositioned radially 
outward from their unstressed position thereby stressing that tangential 
portion and creating a member in tension 93. The member in tension 93, 
having a tangential contact point 96 on the peripheral edge 68 of inner 
drive member 61 imparts a predetermined radially inward force which 
thereby creates a predetermined frictional resistance to rotation between 
tangential contact point 96 and the contacted portion of peripheral edge 
68 of inner drive member 61. The contact teeth 97 positioned at that 
tangential contact point 96 engage ratchet teeth 98 of inner drive member 
61 thereby causing the rotation of outer ring 80 relative to inner drive 
member 61 to occur in a ratcheting manner whenever the frictional 
resistance to rotation provided by gripping means 90 is overcome. 
The previously mentioned combination changing mode of operation is 
accomplished by inhibiting the rotation of outer ring 80 relative to lock 
housing 10 by the insertion of a combination changing pin 89 through 
orienting aperture 88 in outer ring 80 of each of the tumbler wheels 60 
and through one of the orienting apertures 25 and 26 of lock cover 20. The 
inner drive members 61 of the multiple tumbler wheels 60 may then be 
rotated relative to their respective outer rings 80 in response to 
rotational manipulations of the combination lock dial 31. 
Gripping means 90 must impart a predetermined resistance to relative 
rotation that falls within two bounds. The lower bound is the minimum 
frictional resistance necessary to prevent inadvertent rotation of outer 
ring 80 relative to inner drive member 61 during normal, combination 
dialing useage of lock mechansim 30. The upper bound is that the maximum 
frictional resistance to rotation must not be so great that when operating 
in the combination changing mode in a manner which will be more fully 
described, that projection 67 extending within an adjacent groove 65 and 
contacting stop 66 is not sheared or damaged. Accordingly, any number of 
gripping members may be used to comprise gripping means 90 so long as the 
net frictional resistance to rotation is within the bounds. In bench 
testing the preferred embodiment, these lower and upper bounds of 
frictional resistance to rotation to be imparted by gripping means 90 was 
measured to be 20 and 40 inch-ounces of torque, respectively. 
A driver 70 is provided for communicating the rotational motion of the 
combination lock dial 31 into rotation of tumbler wheels 60. In the 
preferred embodiment, driver 70, as shown in FIGS. 1 and 11, has a hollow 
shaft 71 with a circular flange 73 at one end together forming a hollow 
cylinder which is open at the other end. Hollow shaft 71 has an interior 
cylindrical bore which is provided with keyway guides 72. Said bore is 
particularly configured to receive shaft 34 connected with combination 
lock dial 31 such that the keyway guides 72 of the bore engage the keyway 
grooves 35 of shaft 34 causing the dial 31, shaft 34, and driver 70 to 
rotate in a unitary manner. 
Flange 73 on driver 70 has a peripheral edge which includes a cutout 74 
which together act as a cam surface when placed in contact with the driver 
engaging surface 57 of the head 55 of pawl 50. Cutout 74 of driver 70 
operates similar to gate means 85 of each of the multiple tumbler wheels 
60 in that the cutout must be aligned with the head 55 of pawl 50 in order 
to permit unlocking motion of bolt means 40 whenever the lock mechanism is 
in the dead bolt mode of bolt operation. Additionally, cutout 74 is 
further provided with a pawl driving surface 75 which, when the pawl 50 
has been rotated radially inward due to alignment of each of the gate 
means 85 of the multiple tumbler wheels 60 and the cutout 74 of the driver 
70 with the head 55 of the pawl 50, permits a further rotation of dial 31 
to engage the driver engaging surface 75 of pawl 50 and overcome the bolt 
spring 45 causing unlocking motion of bolt means 40. 
Flange 73 of the driver 70 is also provided with a projection 76 similar to 
the projections 67 of the inner drive members 61. Projection 76 is adapted 
to protrude into the groove 65 and contact the stop 66 of an adjacently 
mounted tumbler wheel 60. In this manner, rotation of dial 31 causes 
projection 76 to move in a circular manner within groove 65 of the first 
adjacent tumbler wheel 60 until it encounters stop 66 contained within 
that groove 65. Further rotation in the same directon causes the 
projection 76 of driver 70, due to its contact with stop 66 of the 
adjacent inner drive member 61, to rotate that adjacent tumbler wheel 60 
while the projection 67 of that adjacent tumbler wheel rotates within the 
groove 65 of the next adjacent tumbler wheel. This cooperation continues 
for the projections 67 and grooves 65 of each of the three tumbler wheels 
60 shown in the preferred embodiment. Accordingly, three complete 
rotations of the combination lock dial 31 in any one direction will cause 
each of the projections 67 to be in contact with the stop 66 of the 
adjacent inner drive member 61 such that driver 70 and all three tumbler 
wheels 60 continue to rotate in a unitary manner. Subsequent alternating 
clockwise and counterclockwise rotations in reducing numbers of complete 
revolutions cause each of the inner drive members 61 to acquire an 
independent rotational orientation relative to lock housing 10 and, 
depending on the relative rotational orientation of the stop 66 and 
projection 67 of inner drive member 61 relative to the gate means 85 of 
its respective outer gate 80, each of these rotational orientations 
coincides with a numeric indicia 32 being aligned on lock dial 31 with the 
reference point on face plate 33. Accordingly, the predetermined sequence 
of dial manipulations causes each of the gate means 85 and the cutout 74 
of driver 70 to be aligned with head 55 of pawl 50 thereby permitting 
unlocking operation of bolt means 40 in accordance with the 
combination-dialing mode of tumbler wheel operation. 
The combination-changing mode of tumbler wheel operation may be initiated 
whenever said multiple gate means 85 are in alignment with head 55 of pawl 
50 as when the proper combination has been dialed. In this condition, the 
orienting apertures 88 of each of the outer rings 80 of the multiple 
tumbler wheels 60 are also in alignment with each other and with an 
orienting aperture 25 or 26 on lock cover 20. When in this condition, a 
simple rod-shaped combination changing pin 89 may be inserted in any 
rotational orientation through these apertures 25 or 26, and 88, to 
restrict rotation of each of the outer rings 80 relative to lock housing 
10. Further manipulation of the lock mechanism dial 31 by cooperation of 
the projection 76 of driver 70 with the stop 66 of the adjacent inner 
drive member 61, similarly the projection 67 of that inner drive member 61 
with stop 66 of its adjacent inner drive member 61, and similarly for each 
additional inner drive member 61, causes each of said inner drive members 
61 to overcome the resistance to relative rotation between that inner 
drive member 61 and its respective outer gate ring 80 to produce relative 
rotation therebetween such that each of the inner drive members 61 may 
acquire a new rotational orientation relative to its respective outer ring 
80. By dialing the newly desired sequence of combination dial 
manipulations, the new combination, the combination of the lock is changed 
and each of the tumbler wheels 60 acquires a rotational orientation of its 
outer ring 80 relative to its inner drive member 61 in accordance with 
that new combination. Subsequently, the combination changing pin 89 may be 
removed and the lock will resume functioning in the combination-dialing 
mode, operating to allow motion of bolt means 40 in the unlocking 
direction whenever the new combination has been properly dialed. 
Referring particularly to FIG. 11, the elements of the preferred embodiment 
may be easily assembled during manufacture by the following sequence. 
First, lock housing 10 may be provided and positioned base 11 down such 
that the subsequent parts may be dropped into it. Bolt spring 45 may be 
dropped into the bottom of lock housing 10 such that one end thereof is 
proximate bolt spring mounting means 14. Selection may be made between 
spring-bolt configuration 41 and dead-bolt configuration 43 for the 
desired bolt means 40. Pawl spring 51 may be dropped onto pawl post 48 of 
bolt means 40. Pawl 50 may be similarly positioned on pawl post 48 and 
rotated such that the pawl spring 51 is tensioned between pawl spring stop 
52 of pawl 50 and pawl spring stop 49 of bolt means 40 such that the pawl 
50 is biased to rotate radially inward relative to the journal sleeve 17 
of the lock housing 10. Together the bolt means 40, the pawl spring 51 and 
the pawl 50 assemble as shown in FIG. 10. This assembly may then be 
inserted into lock housing 10 such that the bolt 40 protrudes through bolt 
aperture 16. Bolt spring 45 is positioned relative to the bolt means 40 
such that the other end of the spring is proximate the spring biased 
surface 46 of the bolt means 40 and the spring 45 extends therebetween in 
an operative condition, as particularly shown in FIG. 2. 
Once the bolt means 40, bolt spring 45, pawl spring 51 and pawl 50 have 
been inserted into lock housing 10, each of multiple tumbler wheels 60 and 
spacers 38 may be dropped onto the exterior surface 79 of journal sleeve 
17. More particularly, each tumbler wheel 60 is assembled by snapping an 
inner drive member 61 into the interior of bore 81 of the respective outer 
ring 80 thereby engaging ridge 82 with groove 69, each with a 
predetermined rotational orientation which specifies one of the sequence 
of combination dial manipulations necessary to unlock the lock mechanism 
30. The numeric indicia 84 on outer ring 80 serves to identify that 
portion of the sequence of dial manipulations associated with that 
particular tumbler wheel by identifying that indicia 84 proximate the 
projection 67 of the respective inner drive member 61. 
A first tumbler wheel 60 is positioned about the exterior surface 79 of 
journal sleeve 17 such that its first side 63 is down or adjacent base 11 
of lock housing 10. The tumbler wheel 60 may be then dropped or slid down 
journal sleeve 17 into contact with collar 19. A first spacer 38 may be 
oriented such that the spacer guides 39 align with the aligning grooves 78 
on the exterior surface 79 of journal sleeve 17 and the spacer 38 may be 
slid or dropped down journal sleeve 17 into contact with the first tumbler 
wheel 60. This sequence of assembly repeats for the second and third 
tumbler wheels 60 and spacers 38, respectively. Driver 70 may be inserted 
such that the hollow shaft 71 is inserted into the bore 18 of journal 
sleeve 17 simply by dropping or sliding the driver 70 into said journal 
sleeve 17. 
One of two modes of bolt operation are selected, either spring-bolt mode or 
dead-bolt mode, and lock cover 20 is rotationally oriented such that 
either the spring-bolt indicia 22 or the dead-bolt indicia 23 is 
positioned proximate the bolt aperture 16 of lock housing 10 with the bolt 
portion of bolt means 40 extending therethrough in accordance with said 
selection. Lock cover 20 may then be fitted onto lock housing 10 and 
fastened thereto by the insertion of fastening means, specifically screws 
24, through the mounting apertures 21 of lock cover 20 and into the 
mounting apertures 15 of lock housing 10. 
The assembled lock mechanism 30 within lock housing 10 and lock cover 20 
may then be fastened to the door of an enclosure using mounting screws 36 
and mounting nuts 37 which extend through mounting flanges 77 of lock 
housing 10. Similarly, face plate 33 may be attached to the opposite side 
of the door. Shaft 34 may be inserted through an aperture of the door and 
into contact with the interior of the hollow shaft 71 of driver 70. Dial 
31 may then be press fit onto the end of shaft 34 thereby completing the 
assembly of the lock mechanism. 
Having thus disclosed a preferred exemplary embodiment of a combination 
lock having two part tumbler wheel construction, simple assembly, and 
changeable combination features in accordance with the present invention, 
it should be apparent to those skilled in the art that the present 
invention accomplishes the objectives and attains the advantages discussed 
herein and that various modifications, adaptations, and variations can be 
made within the scope and spirit of the present invention which is limited 
only as defined by the following claims.