US 3419893 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Dec. 31, 1968 c. A. VAHLSTROM PERMUTATION LOCKS Filed June 13, 1966 CARL A. VAHLSTROM ATTORNEYS United States Patent 3,419,893 PERMUTATION LOCKS Carl A. Vahlstrom, New Britain, Conn., assignor to Emhart Corporation, Bloomfield, C0nn., a corporation of Connecticut Filed June 13, 1966, Ser. No. 556,962 7 Claims. (Cl. 70-24) ABSTRACT OF THE DISCLOSURE A lock structure in which a fulcrumed blocking lever is provided which upon pivotal movement in a first direction prevents disengagement of a lock securing element from a lock body. The blocking lever is pivoted on a pivot means intermediate its ends which is releasable from a pivot mounting in the lock body. The blocking means of said lever is on one side of the pivot means and a locking means engages the lever on the opposite side of said pivot means. A single spring engages the blocking lever between the pivot means and the locking means, this single spring means performing the multiple functions of biasing said lever in a second direction out of blocking engagement, biasing said pivot means against its mounting with a relatively strong force, and biasing said blocking lever against said locking means with a relatively light force.
This invention relates to improvements in the permutation lock shown and described in my US. Patent No. 2,853,868.
In that particular permutation lock, two separate and distinct spring means were required to keep the blocking lever in position relative to its fulcrums in the lock case and to bias the blocking lever out of engagement with the shackle locking bolts and into engagement with the control discs. The first spring means was a leaf spring which was positioned between the casing of the lock and the blocking lever directly over the fulcrum points for the latter element. The second spring means was a torsion spring wound about a shaft and acting between the rear wall of the case and the edge portion of a special aperture in the blocking lever through which the spring extended to urge the blocking lever against the control discs and out of engagement with the locking bolts. Aside from the number of parts involved, one of the principal disadvantages of this combination, and of most other permutation locks having'such spring means to bias the blocking lever against the fulcrum points in the relative ease with which unauthorized persons can open the lock through the well-known process of rapping. Also, since the moment arm through which the second spring acts is relatively large, the pressure of the blocking lever against the permutation wheels is relatively great and unscrupulous persons attempting to open the lock can feel the change that takes place in the resistance to the turning movement of the wheels when the combination has been set.
The present invention overcomes this and other disadvantages of my prior permutation lock by providing spring means which urge the blocking lever against the control discs with relatively light force, yet holds the blocking lever against its fulcrum points with a relatively large force, thus making unauthorized opening of the look by feel or rapping virtually impossible.
My improved device does away with the need for separate spring means to retain the blocking lever in operative position and for biasing the blocking lever into engagement with the control discs and out of engagement with the shackle locking bolts. I accomplish this dual result by means of a single, conical, compression spring positioned between the casing of the lock and the blocking lever.
3,419,893 Patented Dec. 31, 1968 My improved device, because it takes the place of two spring means, while retaining the function of both, makes the permutation locks wherein it is found less expensive and easier to manufacture. Also, because there is one less spring, there is less likelihood of mechanical failure.
Further, because my improved device uses a conicalshaped coil spring, with the base of the cone bearing against the inside of the lock case, a greater force is placed on the blocking lever at the point of contact between the spring and the blocking lever than if any other type of spring were used. This greater force per unit of spring length concentrated at a particular point on the blocking lever allows for greater efficiency and maximum utilization of the potential energy of the spring.
Therefore, the primary object of my invention is to provide improved locking means wherein only one spring means is required to position and actuate the blocking lever through its cycle of operation.
A further object of this invention is to provide an improved spring means for a permutation padlock which will prevent the opening of said lock by unauthorized persons not having knowledge of the combination and attempting to open the padlock by feel or by rapping.
Further advantages and objects will become readily apparent from the following description and accompanying drawings wherein:
FIG. 1 is a perspective view of a permutation padlock having therein the improved mechanism.
FIG. 2 is a sectional front elevational view of the improved padlock with a portion of the lock case removed to reveal the working mechanism.
FIG. 3 is a sectional side elevational view taken along the line 33 of FIG. 2.
FIG. 4 is a sectional plan view taken along the line 4-4 of FIG. 2.
FIG. 5 shows a modification of the improved blocking lever.
FIG. 6 shows another modification of the improved blocking lever.
Referring to the drawings in detail, wherein like numerals indicate like elements, there is shown the case 1 of a padlock having operatively connected thereto a securing element in the form of a shackle 2 that is biased toward unlocked or open position by means of a spring 3.
The shackle locking means embodied in the instant invention includes a pair of oppositely disposed locking bolts 4, 5 which are biased in opposite directions by a spring 6 positioned therebetween and retained on a pin 7, into oppositely disposed notches 8, 8a in the legs of the shackle 2.
The control mechanism for said locking bolts is preferably of the permutation type and is supported by a frame 9 which is received in cavity 10 of the case of the padlock 1. Said frame 9 is secured to said case 1 by means of a blind rivet 11.
The permutation mechanism includes a plurality of permutation wheels 12 carried on a shaft 13, said shaft being longitudinally shiftable in bearings 14, 15 in the frame 9. The shaft carries a disc 17 which is affixed to one end thereof outside of said frame 9 and is urged toward the normal position by means of a spring 16 wound around said shaft and acting between the disc 17 and the outside wall of the frame 9. Each of the wheels 12 is operatively engaged with a lock controlling element 18 in the form of a disc which is rotatably mounted on the shaft 13 and is cut away at one side thereof to provide a fiat surface 18a on the periphery of said disc. For proper operation of a device of this type, it is imperative to provide means for holding the permutation wheels 12 in set position. For this purpose, a series of notches are cut on the periphery of each of the permutation wheels and a series of spring members 19, one for each permutation wheel, are mounted on the wall of the frame 9 and are biased into the individual notches as the permutation wheels are turned.
A blocking lever 20 having a pair of control disc engaging fingers 22 and a blocking finger 25 is pivotally mounted intermediate its ends on side walls 21, 21 of the frame 9. The fingers 22 extend between the permutation wheels 12 and are disposed immediately adjacent the control discs 18. The blocking finger 25 is insertable between the ends of the locking bolts 4, (see FIG. 4) to retain said bolts in locking position in the notches 8, 8a. The blocking lever 20 is retained in operative position and is actuated by a single, conical-shaped, coiled compression spring 23. The spring 23 is disposed between the Wall of the cavity in the padlock case 1 and the blocking lever 20. In the embodiment shown in FIG. 3, the base of the conical-shaped spring 23 merely rests against the wall of the cavity 10 while the apex of the spring is seated in a specially designed cup 24 mounted in a hole in said blocking lever 20. In the embodiment shown in FIG. 4, a seat 32 for the base portion of the spring is cut into the wall of the cavity 10 to positively locate the spring.
FIG. 5 shows a modified securing means for retaining the conical-shaped spring in operative engagement with the blocking lever A recess 27 is punched into the blocking lever 20' and the apex of the spring 23 is directly inserted therein when the improved padlock is assembled.
In FIG. 6 a further modification is shown for retaining the spring 23 in operative engagement with the blocking lever 20". Here a stud 28 is formed on the blocking lever 20", and when the improved padlock is assembled the apex of the coil spring is inserted over said stud.
At one side of the blocking lever 20 there is provided an arcuately curved extension 26 which is disposed in the space between the disc 17 and the side of the case 9 and which is designed to enter that space and prevent movement of the shaft 13 when the blocking lever is in locked condition.
The operation of the improved permutation lock mechanism is as follows:
When the mechanism is in locked position, the blocking lever 20 is held by the compression spring 23 in contact with the control discs 18, so that blocking finger of said lever is positioned between the locking bolts 4, 5 and interferes with the inward movement of said locking bolts out of the notches 8, 8a in the shackle 2 thereby retaining the shackle in locked position. It will be evident that any attempt to pull the shackle 2 outwardly while the locking bolts 4, 5 are engaged in notches 8, 8a, will tend to cam said locking bolts into tighter engagement with the finger 25.
When it is desired to unlock the shackle 2, the control discs 18 are properly positioned by rotating their respective permutation wheels 12 until the proper combination appears on said wheels. All of the fiat sides of the control discs will then be aligned and will be adjacent to the cooperating fingers 2222 at the lower end of the blocking lever 20. The shackle is then depressed to permit the locking bolts 4 and 5 to move apart under the influence of the spring 6 and out of interlocking engagement with the blocking finger 25, whereupon the spring 23 will force the end of the blocking lever inwardly and pivot it about its fulcrums 21-21 to swing the blocking finger 25 outwardly from between the locking bolts 4, 5. When the shackle is released, it is projected into unlocked or open position by the spring 3 which is designed to overcome the force exerted by the spring 6.
When it is desired to lock the said mechanism, either of the two methods may be used. In the first method the permutation wheels 12 are rotated to the proper preselected combination. This causes a corresponding movement of the control discs 18 bringing all the flat surfaces 18:: into alignment immediately adjacent the fingers 22 of blocking lever 20. As the last of the permutation wheels are rotated to bring all the flat surfaces 18a of the discs 18 into alignment, spring 23 pivots blocking lever 20 about its fulcrum 2121 to move blocking finger 25 outwardly, away from locking bolts 4, 5. Locking bolt 4 is then biased outwardly under the influence of spring 6 into the shackle receiving shaft 29; locking bolt 5 is retained in position by surface 31 of shackle 2 pressing up against the nose portion 30. The shackle 2 is then moved downwardly to telescope the shackle into the locking mechanism. Locking bolt 4 will first be cammed back out of shaft 29 as the shackle descends thereby compressing spring 6, the bolt will then snap into notch 8 under the biasing action of spring 6 as notch 8 comes into position. Locking bolt 5 will snap into notch 8a also under the biasing action of spring 6 as notch 8a comes into position. The permutation wheels are then arbitrarily rotated. This causes the discs 18 to correspondingly rotate, bringing the arcuate surfaces to bear against the blocking lever 22. The resultant camming action urges the blocking lever to pivot about its fulcrums 2121 and moves the blocking finger 25 into engagement with looking bolts 4, 5 to prevent them from moving out of engagement with notches 8, 8a thereby securing the shackle 2 in the lock mechanism and preventing its removal.
In the second method the permutation wheels are rotated to any number combination while the shackle is outside the lock mechanism. The rotation of the permutation wheels causes a corresponding rotation of the control discs 18 bringing the arcuate surfaces to bear on the blocking lever fingers 22. The resultant camming action caused by the spring 23 and the arcuate surfaces of control discs 18 urges blocking lever 20 toward locking bolts 4, 5. Locking bolt 5, because of its engagement with surface 31 of shackle 2, blocks the path of blocking lever 20. This causes blocking lever 20 to be lifted off its fulcrum 2121 and into pressing engagement with locking bolt 5. As the shackle 2 descends and the notches 8, 8a align themselves with locking bolts 4, 5 the pressure of blocking lever 20 and spring 6 urges the locking bolts 4, 5 into engagement with the notches 8, 8a and locks them in position, thereby securing the shackle 2 in the lock mechanism and preventing its removal.
What is claimed is:
1. In a locking device, the combination comprising a lock body;
a securing element movablelinto and out of engagement with said body;
a pivotal mounting in said body;
a blocking lever releasably but pivotally mounted thereon in said body on a pivot means intermediate its ends, said blocking lever having means on one side of said pivot means which upon pivotal movement of said blocking lever in a first direction will prevent disengagement of said securing element from said lock body;
a locking means immediately adjacent said blocking lever on the opposite side of said pivot means for moving and holding said blocking lever in said first direction of pivotal movement; and
a single spring means engaging said blocking lever between said pivot means and said locking means, said spring means exerting a bias on said lever in a direction to normally hold said releasable pivot means on said mounting and to urge said blocking lever in a second direction of pivotal movement opposite to said first direction; said single spring means holding said lever on said pivotal mounting with a relatively strong force, and biasing said blocking member against said locking means with a relatively light force.
2. The locking device as defined in claim 1 wherein said lock body has at least one spring urged locking bolt to operatively engage said securing element when said securing element is in engagement with said lock body, said blocking lever operatively engaging said locking bolt when said lever is pivotally moved in said first direction to prevent retracting movement of said locking bolt and thereby prevent disengagement of said securing element from said lock body.
3. The locking device defined in claim 1 wherein said single spring means comprises a helical compression spring biased between a portion of said lock body and said blocking lever; and means to retain said spring in operative position between said blocking lever and said portion of said lock body.
4. The locking device defined in claim 1 wherein said single spring means comprises a conically shaped, coiled compression spring biased between a portion of said lock body and said blocking lever, and means to retain said spring in operative position between said blocking lever and said portion of said lock body.
5. The locking device defined in claim 3 wherein said last mentioned retaining means comprises a recess cut in said blocking lever and a cup inserted in said recess, said helical spring being accepted directly into said cup when said locking device is in assembled relationship.
6. The locking device defined in claim 3 wherein said last mentioned retaining means comprises a cup-shaped recess formed in said blocking lever, said helical spring being accepted directly into said cup-shaped recess when said blocking lever is positioned in said lock body.
7. The locking device defined in claim 3 wherein said last mentioned retaining means comprises a pin formed on said blocking lever, said spring being accepted on said pin when said locking device is in assembled relationship.
References Cited UNITED STATES PATENTS 2,114,073 4/1938 Denerich -25 2,183,168 12/1939 Pond 70-25 2,183,792 12/1939 Eden 70-25 2,853,868 9/1958 Vahlstrorn 70-24 MARVIN A. CHAMPION, Primary Examiner.
EDWARD J. MCCARTHY, Assistant Examiner.
Disclaimer 3,419,893.-0(17Z A. Vahlstrmn, New Britain, Conn. PERMUTATION LOCKS. Patent dated Dec. 31, 1968. Disclaimer filed Feb. 23, 1977, by the assignee, E'mhart Industries, Inc. Hereby enters this disclaimer to claims 1, 2, 3 and 7 of said patent.
[Ofiicial Gazette May 3, 1.977.]