Note: Descriptions are shown in the official language in which they were submitted.
76
BACKGROUND OF THE I~VENTION
This invention relates to padlocks, and r.lore
particularly to the latch mechanism which functions -to lock
and release the padlock shackle.
All padlocks, whether of the permutation -type, the
key operated type, or of the combination permutation and key
operated type, necessarily include a latch mechanism which,
at one time functions to hold the padlock shackle in its
locked position, and at another time functions to release the
shackle for movement to its open position. The latch mech-
anism has become more or less standardized in that a
spring-biased latch bolt slidably carried in a pivoted rocker
engages a notch formed in the padlock shackle. This engage-
ment of the latch bolt in the shackle notch prevents upward
movement of the shackle to its open position.
Means well known and established in the art are
utilized to disengage the latch bolt from the shackle notch
by pivoting the rocker, as in permutation type padlocks, or
by sliding the latch bolt into the rocker, as in key operated
padlocks. Such disengagement permits upward movemen-t of the
shackle to its open position whereupon the la-tch bolt is
slidably returned to its original disposition. Downward move-
ment of the shackle to a locked position involves moving the
shackle against the latch bolt and sliding the latch bolt
back into the rocker until thc shackle notch is aligned with
the latch bolt, whereupon the latch bolt slides into
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engagement with the shackle notch.
As described, after the latch mechanism functions to
unlock the padlock, the spring-biased latch bolt returns to
its original disposition automatically and will then interact
with the shackle to relock the padlock without subsequent
manipulation of the padlock key or the padlock combination
dial. Unfortunately, the advantages afforded by the spring-
biased latch bolt are somewhat offset by -the disadvantage
that such a latch bolt is subject to forceful and man-
ipulative tampering designed to open this type of padlock. A
sharp blow against the padlock casing with simultaneous or
repetitive tapping of the padlock shackle in a particular
manner can cause the latch bolt to move into the rocker
sufficiently to permit upward movement of the shackle, thus
"springing" or opening the padlock.
The present invention is designed to overcome the
tampering aspect of this type of padlock by providing means
to limit or res-trict the sliding movement of the latch bolt
in -the rocker.
SUMMARY OF THE INVENTION
With the above background in mind, it is the object
of this invention to provide a latching mechanism utilizing a
spring-biased latch bolt slidably disposed within a rocker
wherein the latch bolt has limited sliding movement into the
rocker when the padlock shackle is interlocked with the latch
bolt. Specifically, the latch bolt must be prevented from
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sliding into the rocker and disengaging the shackle except
when such disengagement is accomplished through manipulation
of a padlock key.
To this end, a latch bolt having parallel top and
bottom flat surfaces with two spaced-apart shoulder portions
extending upwardly from the top surface is slidably mounted
in a recess in the rocker member. One of the two shoulder
portions is disposed outside of the rocker recess while the
other shoulder portion is disposed in an enlarged portion of
the recess within the rocker. The said other shoulder portion
acts as a fulcrum in cooperation with associated spring means
to urge the top surface of the latch bolt in-to abutment with
the top wall of the recess, whereby said one shoulder portion
disposed outside of the rocker acts as a stop to prevent the
latch bolt from sliding into the rocker recess.
DESCRIPTION OF THE DRAWINGS
Fig. 1 is a front elevational view of a padlock
embodying the teachings of the invention set forth herein.
Fig. 2 is a vertical sec-tional view taken along
lines 2-2 of Fig. 1.
Fig. 3 is a vertical sectional view taken along
lines 3-3 of Fig. 2 showing the latching mechanism in
"locked" position.
Fig. 4 is an exploded perspective view of the
spring-biased latch bolt and rocker assembly comprising the
latch mechanism.
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Fig. 5 is a vertical sectional view similar to Fig.
3 but showing rota-tion of the latch mechanism to an
"unlocked" position and with portions of the disc members
broken away.
Fig. 6 is a view similar to Fig. 5 but with the disc
members completely broken away and showing the shackle
approaching an open position.
Fig. 7 is a fragmentary vertical sectional view
similar to Fig. 6 but showing the shackle moved downwardly
into the padlock body.
Fig. 8 is a view similar to Fig. 7 showing the latch
bolt pivoted by the downward movement of the shackle.
Fig. 9 is a view similar to Fig. 8 showing the latch
bolt slid into the rocker by further downward movement of the
shackle.
DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now -to the drawings and specifically to
Figs. 1, 2 and 3, the reference numeral 10 indicates a
padlock comprising a body member 11 and a shackle 12. The
body member 11 is comprised of a cylindrically shaped shell
14 having a back wall 15 and side wall 16, and a front plate
18 secured to said side wall by a rolled over flange as
indicated at 19. The shackle 12 is u-shaped having a long leg
12a and a short leg 12b extending through side wall openings
16a and 16b, respectively. The short leg 12b has a locking
notch 20 formed therein adjacent its terminus, which terminus
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has a bevel or cam surface 12c, and the long leg 12a has a
guide member 21 secured thereto at its terminus, the
func-tions of which will be described later.
A circular dial 22 having a knurled o~ter wall 23
and the numerical markings indicated by reference numeral 24
has a hollow stem portion 26 extending through an opening 27
in the shell front plate 18 to abutment with and securement
to a first disc member 28. A shaft 29 formed integral with
the back wall 15 extends through the hollow stem 26 thereby
providing an axle about which the dial 22 can be rotated and
has a cap member 30 press fitted thereon. A second disc 31
and a third disc 33 rotatably mounted on shaft 29 can be
rotated by and in coordination with the first disc 28 in a
manner well known in the art to align peripheral notches in
the discs, as indicated by reference numeral 35 in Fig. 5.
Inasmuch as the construction and operation of the dial and
disc assembly is all conventional and, as such, does not con-
stitute a part of the invention disclosed herein, no detailed
description is necessary Eor a complete understanding of said
invention. Aiso mounted on shaft 29 is a disc upsetter 36 and
a compression spring 38, the function of both to be described
later.
Referring to Fig. 2, a journal 40 formed in the back
wall 15 is aligned with a similar journal 41 formed in the
front plate 18, and together they provide bearing surfaces
for a rotatable locking mechanism 44 mounted therein and
disposed between the back wall and front plate. The locking
:
333~37~i
mechanism 44 comprises a housing member or rocker 45, a latch
bolt 46, and-~a spring 48 which, as shown, function as a
unitary element to maintain the padlock in a locked position,
as will now be described.
As shown in Flgs. 3 and 4, the rocker 45 is formed
to provide a recess 50 the~rein having parallel top and bottom
walls, 51 and 52, respectively, defining an opening 53, and a
back wall 54. The top wall 51 is formed to provide an
enlarged portion 55 in the recess 50 remote from said opening
53 defining a ledge 56, and the bottom wall 52 is formed to
provide an upstanding stop member 58 in approxi~ate vertical
alignment with said ledge 56. An arcuate tongue 59 extending
outwardly and downwardly from the rocker 45 in diametric
opposition to the recess opening 53 is disposed adjacent the
peripheries of discs 28, 31 and 33, the purpose for which
will be described later.
The latch bolt 46, best seen in Fig. 4, has parallel
top and bottom flat surfaces 61 and 62 respectively. The top
surface 61 has two spaced-apart shoulder portions extending
upwardly therefrom, one shoulder portion being designated by
the reference numeral 63 and -the other shoulder portion being
designated by the reference numeral 65. The bottom surface 62
has a shoulder portion 66 extending downward]y therefrom
which is connected to the other shoulder portion 65 of the
top surface 61 by a Elat vertical back wall 67. The one
shoulder portion 63 of the top surface 61 is connected to the
bottom wall 62 by an inclined front wall 68.
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37~
Referlng again to Fig. 3 a spring 4~ disposed
between the back wall 54 of the recess 50 and the back wall
67 of the latch bolt 46 urges the latch bolt out of the
recess 50 so tha-t front wall 68 of said latch bolt is
disposed within the locking notch 20 of the shackle 12. This
bias of spring 48 against back wall 67 moves the shoulder
portion 65 of latch bolt 46 into abutment with ledge 56 of
rocker 45 which acts as a fulcrum to pivot the latch bolt 46
upwardly so that the latch bolt top surface 61 abuts -the top
wall. 51 of the rocker recess 50. In this condition, forceful
and manipulative tampering cannot move the latch bolt 46 out
of engagement with lockinq notch 20 since shoulder portion 63
cooperates with the rocker 45 to limit sliding movement of
the latch bolt 46 into the recess 50. Not only is the shackle
12 locked by the latch bolt 46, but latch bolt 46 is locked
by the rocker 45, thus effecting a "double-lock" for the
padlock.
As shown, any movement of the shackle 12 upwardly
will cause locking notch 20 to apply upward pressure against
latch bolt 46 thereby urging rotation of rocker 45 in a
clockwise direction. However, such rotation will move the
tongue 59 into abutment with the peripheral portions of discs
28, 31 and 33 thereby preventing further ro-t~tion of the
rocker 45, and thereby maintaining the interlocking relation-
ship between shackle notch 20 and ].atch bolt 46.
Manipulation of dial 22 through a correct combin-
ation has, in a wel.l known manner and as shown in Fig. 5,
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rotated the discs 28, 31 and 33 to align peripheral notches
in the discs, as indicated by reference numeral 35. Movement
of shackle 12 upwardly moves shackle notch 20 upwardly
aqainst latch bolt 46 causing clockwise rotation of the
locking mechanism 44, such rotation bèing permi-tted since the
aligned notches 35 allow tongue 59 to move past the periphery
of discs 28, 31 and 33. This is an "unlocked" position of the
locking mechanism 44 and permits the shackle short leg 12b to
be moved upwardly and Ollt of locking engagement with the
latch bolt 46. As shown, the disc upsetter 36 has a short
lever arm 81 and a long lever arm 82 which bracket the
shackle guide 21, and the upward movement of shackle 12 also
moves shackle guide 21 upwardly against the upsetter short
lever arm 81 thereby rotating upsetter 36 counter-clockwise.
As shown in Fig. 6, continued movement of the
shackle 12 upwardly continues the rotation of upsetter 36
causing the cam surface 83 to act against the tongue .S9
thereby rotating the rocker in a counter-clockwise direction
and back to its orisinal locking engagement disposition.
Af~er the tongue 59 has been cammed out of the aligned
notches 35 of the discs 28, 31 and 33 as described, further
movement of the shackle 12 upwardly and out of the body
member 11 will further rotate upsetter 36 and, as will now be
explained, cause rotation of disc 33.
As seen in Fiy. 2, compression spring 38 places an
axial thrust on upsetter 36 urging it into contact with disc
33. This contact or frict:ional engagement causes disc 33 to
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76
be rotated along with rotation of upsetter 36 except when
disc 33 is otherwise engaged, as by the tongue 59. Rotàtion
of disc 33 by upsetter 36 is independent of discs 28 and 31
and, accordingly, such rotation moves the notch of disc 33
out o~ alignment with the notches of discs 28 and 31.
Referrlng now to Figs. 7, 8 and 9, there is shown,
in sequence, the action between the shackle leg 12b and the
latch bolt 46 as the shackle 12 is moved downwardly from the
open position to a locked position. As shown in Fig. 7, down-
ward movement of the shackle 12 places shackle leg 12b into
abutment with the inclined wall 68 of latch bolt 46.
Continued downward movement of shackle 12 pivots the latch
bolt 46 downwardly about the fulcrum formed by shoulder por-
tion 65 and ledge 56, to the position shown in Fig. 8,
wherein the bottom surface 62 of the latch bolt abuts the
bottom wall 52 of the recess 50. Continued downward movement
of shackle 12 causes the shackle cam surface 12c to act
against the latch bolt inclined wall 68 and slide the latch
bolt 46 into the recess 50 of the rocker 45 as shown in Fig.
9. As also seen in Fig. 9, the downward movement of the
shackle 12 has moved the shackle guide 21 downwardly against
upsetter arm 82 thereby rotating upsetter 36 clockwise
towards return to i-ts initial position. Further downward
movement of shackle 12 aligns the locking notch 20 with the
recess 50 and permits movement of the spring-biased latch
bol-t 46 into locking engagement with said locking notch, as
shown in Fig. 3.
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While I have described my invention in terms of a
permutation type lock it is, of course, equally applicable to
a key operated lock. There are many styles of key operated
lever arrangements that can be utilized to manipulate the
latching mechanism 4~ to remove the làtch bolt 46 from ]ock-
ing engagement with the locking notch 20, but since they are
not necessary to the invention, nor to understanding the
invention, they are considered the equivalent of the permu-
tation style of unlocking the padlock. Whether permutation
type, key type, or a combination of these, the invention is
directed to improving the security of a padlock whose shackle
is held in a locked position by a spring-biased bolt member.
Having described by invention in terms of a prefer-
red embodiment, it should be obvious that modifications are
possible within the teachings described herein without
departing from the scope of the invention as hereafter
claimed.
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