US2881612A - Combination lock construction - Google Patents

Description

April 14, 1959 c. N. SMITH ETAL 1 COMBINATION LOCK CONSTRUCTION Filed Sept 19. 1955 5 Sheets-Sheet 1 4 INE/ENTOR S ChwrlesNonws Swill g; Frederic]; elBremer d 3| ATTORNEYS April 14,1959 c. N. SMITH ETAL j 2,88 1,61 2;

COMBINATION LOCK CONSTRUCTION Filed Sept. 19. 1955 5 Sheets-Sheet 2 INVENTORS Chwrbes Norris Smilz m Frederalz J. Bremer '2 ATTORNEYS P 1959 C.'N. YSMITH E TALQ I 7 2,881,612

COMBINATION LOCK CONSTRUCTION Filed Sept." 19. 1955 5 Sheets-Sheet 3 INVEN TORS Charles Norris Smifilz g Frederick dBremer d ATTORNEYS April 14, 1959 c. N. SMITH ETAL COMBINATION LOCK CONSTRUCTION 5 Sheets-Sheet 4 Filed Sept. 19. 1955 INVENTORS Charles Norris J Bremer '52 M} F rederia'k ATTORNEY;

April 14, 1959 c. N; SMITH ET AL 2,881,612

COMBINATION LOCK CONSTRUCTION I 5 Sheets-Sheet 5 Filed Sept. 19. 1955 m w Q a I I m H v L H H MM w l a w d 6 I a m H I I Frederick J Brenner ATTORJVEKQ United States Patent() COMBINATION LOCK CONSTRUCTION Charles Norris Smith, North Canton, and Frederick J. Bremer, Hamilton, Ohio Application September 19, 1955, Serial No. 535,026

13 Claims. (Cl. 70-302) Our invention relates to improvements in combination lock construction and more specifically to a combination lock construction having improved manipulation-proof features. Certain prior constructions of combination locks have included the usual slotted tumblers rotatably mounted on a dial shaft and working in conjunction with a fence for withdrawing certain bolt work when properly set. Further in some cases the dial shaft has been provided with a cam member upon which the fence normally rides, spaced radially from the outer extremity of the tumblers, with the dial shaft and consequently the cam member being axially movable to permit the fence to engage in the tumbler slots when these slots are aligned.

Some of these prior constructions of combination locks have been relatively manipulation-proof in theoretical design, that is, if it were possible to construct these locks exactly according to specification. It is almost impossible, however, to construct these locks exactly according to specification even though each lock were handmade, and the tolerances required for modern mass production of such locks has completely eliminated any consideration of having the locks perfectly uniform and to exact size, that is, to the point of making them manipulation-proof.

Taking, for instance, a combination lock having the usual axially movable dial shaft and a tapered cam member upon which the fence may ride during the setting of the tumblers, because of the usual mass production discrepancies, it is possible for an unauthorized person to measure, the exact point at which the fence strikes the tapered surface of the cam member when the dial shaft is moved between its axial positions. Further, by taking a series of measurements during a set pattern of manipulation of the lock, it is possible to determine when the slots of the various tumblers are aligned so that the combination of the lock can be discovered and access gained to the particular vault or safe to which the lock is attached.

It is desirable, therefore, to provide some means for making the point at which the fence strikes the tapered surface of the cam member when the dial shaft is moved between its axial positions, so that an unauthorized person cannot surreptitiously determine the combination of the particular lock.

It is, therefore, a general object of the present invention to provide a combination lock construction which overcomes the stated difiiculties and disadvantages of the prior constructions and has improved manipulation-resistant qualities.

It is a further object of the present invention to provide a combination lock construction having an axially tapered cam member arranged so that the lever tongue normally rides on a continuously circumferentially extending cam sunface spaced radially outwardly and axially from the entrance to the cam engagement or drive slot and in which contact between the cam and cam engagement or drive slot is masked.

It is still a further object of the present invention to provide a combination lock construction in which the fence connected to the masked-contact lever arm is normally held by the lever arm in a position spaced from the outer peripheries of the tumblers.

It is another object of the present invention to provide a combination lock construction in which separate contact concealment or false engagement indicating means is provided for masking thepoint of engagement of the lever or cam follower tongue with the tapered cam surface as the dial shaft is moved axially outwardly.

It is still another object of the present invention to provide a combination lock construction in which guide means is provided for maintaining the lever arm movable in a predetermined radial path or plane in reference to the cam member and dial shaft, thereby insuring that the false engagement means will mask the engagement of the cam follower tongue with the tapered cam surface. 5

Finally it is an object of the present invention ,to provide a combination lock construction in which the cam member is formed from a non-metallic preferably plastic material, such as nylon, so that the engagement of the false engagement means and the engagement of the lever tongue with the tapered cam surface, are mufiied and thereby, difli cult to discern.

These and other objects are accomplished by the parts, constructions, arrangements, combinations and subcombinations comprising the present invention, the nature of which is set forth in the following general statement, a preferred embodiment of whichillustrative of the best mode in which applicants have contemplated applyingthe principlesis set forth in the following description and illustrated in the accompanying drawings, and which is particularly and distinctly pointed out and set forth in the appended claims forming a part hereof.

The improved manipulation-proof combination lock construction comprising the present invention may be stated generally as being included in a combination lock having the usual slotted tumblers rotatably mounted through lost motion driving connections on an axially movable dial shaft, with said look also having a tapered cam member mounted thereon working in co-operation with the usual fence member for Withdrawing and extending the usual bolt member. The improvements to such a lock include a false engagement means separate from the fence member and engageableupon axial movement of the dial shaft for providing a false engagement which can be confused with the engagement between the tapered cam member and fence member. This false engagement means may be preferably mounted for engagement with the cam member upon axial movement of the dial shaft and also preferably may include a series of axially spaced spring-pressed balls engageable by the cam, with the cam member also preferably being formed with a circumferentially extending groove to further increase the efliciency of the false engagement means.

It should be understood that this false engagement means is something completely separate from the fence member and its usual cam follower tongue, and in its preferred form is something separately engageable by the cam member independent of the engagement of the cam member with the fence member or any attachment thereto. Further, in order for the false engagement means to most effectively mask the engagement of the cam member with the fence member, it is preferable for the cam member to engage at least part of the false engagement means normally at a different time than the time of engagement of the cam member with the fence member.

Finally, to provide for greater efliciency of the false en gagement means, it is preferable to mount the fence mem-' ber radially movable in a guide slot, requiring movement of the fence member and cam follower tongue in a'predetermined plane perpendicular to the axis of the dial shaft, and also to form the cam member of av sound and 3 vibration deadening material, such as nylon, so that even the normal engagement between the cam member and metal fence member is not easily discernible.

By way of example, an embodiment of the combination lock construction of the present invention is illustrated in the accompanying drawings forming a part hereof wherein like numerals indicate similar parts throughout the several views and in which:

Fig l is a rear elevation of the combination lock constructron of the present invention with the rear cover plate thereof removed, the dial shaft and cam member in normal maximum forward position, the bolt member in extended or locking position, and the cam follower tongue nding on the continuous circumferential surface of the cam member maintaining the fence spaced upwardly from the outer peripheries of the tumblers;

Fig. 2, a front elevation of the rear cover plate in a position folded downwardly 180 from a position for assembly with the parts shown in Fig.1;

3, a vertical section, part in elevation, looking in the direction of the arrows 3-3 in Fig. 1 with the rear cover plate in place;

Fig. 4, a front elevation of the combination lock construction illustrating the dial and dial ring thereof;

Fig. 5, a horizontal section, part in elevation, through the dial shaft of the combination lock construction in the position illustrated in Fig. 1, with the rear cover plate in place; 7

Fig. 6, a vertical section, part in elevation, looking in the direction of the arrows 66 in Fig.

Fig. 7, a view similar to Fig. l, with the dial shaft and cam member moved axially to their rearmost position, and with the bolt member in extended position, the cam follower tongue engaged in the cam drive notch, and the fence located in the tumbler notches;

Fig. 8, a view similar to Fig. 7, with the bolt member in retracted or unlocked position, the cam follower tongue engaged in the cam drive notch, the fence located in the tumbler notches, and the cam member rotated to boltretracted position;

, Fig. 9, a vertical section, part in elevation, looking in the direction of the arrows 9--9 in Fig. 7, illustrating the various parts of the combination lock construction, when the dial member is pressed inwardly moving the dial shaft and cam member axially to their rearmost position, with the cam follower tongue engaged in the cam drive notch and the fence located in the tumbler notches, and with the normal position of the dial member being illustrated in dot-dash lines;

Fig. 10, a fragmentary rear elevation of the combinatio lock construction with the rear cover plate partially broken away, the dial shaft and the cam member in their maximum rearward position, the tumbler notches misaligned, and the fence riding on the outer peripheries of the tumblers, and with the first or rearmost positioned false engagement spring-loaded ball member engaged with the cam member tapered surface forwardly adjacent the cam member circumferential groove;

Fig. 11, a sectional view looking in the direction of the arrows 11-11 in Fig. 10 and taken through the cam follower tongue and the first spring-loaded ball member;

Fig. 12, a schematic view illustrating the position of the fence in reference to the outer peripheries of the tumblers, the cam follower tongue in reference to the tapered cam surface, and the false engagement spring-loaded ball members in reference to'the circumferetnial groove formed in the taperedcam surface, when the cam member is in the position illustrated in Figs. 10 and 11;

Fig. 13, a sectional view similar to Fig. 11, but with the cam member moved axially forward to a position wherein the first spring-loaded ball member is engaged in the cam groove;

Fig. 14, a schematic view similar to Fig. 12 illustrating the positioning of the various parts when the cam member is in the position illustrated in Fig. 13;

Fig. 15, a view similar to Fig. 10, but with the cam member moved axially forward and the second rearmost positioned false engagement spring-loaded ball member engaged in the cam groove;

Fig. 16, a sectional view looking in the direction of the arrows 1616 in Fig. 15;

Fig. 17, a schematic view illustrating the position of the various parts when the cam member is in the position illustrated in Figs. 15 and 16;

Fig. 18, a view similar to Fig. 15, but with the cam member moved axially forward to a position wherein the third rearmost false engagement spring-loaded ball member is engaged in the cam groove;

Fig. 19, a sectional view looking in the direction of the arrows 1919 in Fig. 18;

Fig. 20, a schematic view illustrating the position of the various parts when the cam member is in the position illustrated in Figs. 18 and 19;

Fig. 21, a view similar to Fig. 18, but with the cam member moved axially forward to a position wherein the third spring-loaded ball member has just left the cam groove and the fourth or forwardmost spring-loaded ball member has not yet engaged the cam groove, and the cam follower tongue has just engaged the tapered cam surface, but has not begun to raise the fence from the outer peripheries of the tumblers;

Fig. 22, a sectional view looking in the direction of the arrows 22-22 in Fig. 21;

Fig. 23, a schematic view illustrating the position of the various parts when the cam member is in the position illustrated in Figs. 21 and 22; I

Fig. 24, a view similar to Fig. 21, but with the cam member moved axially forward to a position wherein the forwardmost spring-loaded ball member has engaged in the cam groove, the cam follower tongue is engaged with and has moved axially up the tapered cam surface, and the fence has moved to a position spaced upwardly from the outer peripheries of the tumblers;

Fig. 25, a sectional view looking in the direction of the arrows 25-25 in Fig. 24;

Fig. 26, a schematic view illustrating the position of the various parts when the cam member is in the position illustrated in Figs. 24 and 25; and

Fig. 27, a schematic view illustrating the position of the various parts when the cam member has moved axially forward to its forwardmost position or the position illustrated in Fig. 3. 1

The improved manipulation-proof combination lock construction of the present invention, as seen in Figs. 1 through 6, includes a case, generally indicated at 30, mounted on the inner face 31 of a door which may be the door of a safe or the like, and the lock may be used for stopping bolt work, not shown, in a usual manner. Much of the lock construction illustrated is of conventional construction, such as shown, for instance, in Abbott et al. Patent No. 1,956,304. The present improvements are incorporated in this conventional construction, and these improvements comprising the present invention are hereinafter discussed in detail.

The front face 32 of case 30 is provided with an aperture 33 formed therethrough providing a hollow cylindrical portion 34 therein, and the case 30 is positioned on the door, so that the aperture 33 is in axial alignment with a somewhat smaller aperture 35 in the door. A dial ring 36 is mounted on the outer face 37 of the door. The ring 36 is provided with an outwardly opening annular recessed portion 38 which terminates centrally in a hollow cylindrical portion 39, forming a centrally located aperture 40 in dial ring 36, and the aperture 40 is somewhat larger in diameter than the aperture 35 in the door.

A hollow cylindrical tube 41 is located in aperture 33 formed by cylindrical portion 34. One end of tube 41 abuts the inner face 31 of the door, and the tube extends through aperture 33 and into the confines of the case. The outer diameter of tube 41 is less than the diameter of the aperture 33 from the inner face 31 of .the door to the inner end of the cylindrical portion 34, and tube 41 then has a diameter slightly larger than the aperture 33 from the inner end of portion 34 to the inner end of tube 41 extending in case 30. The inner diameters of tube 41 are similarly formed of reduced and increased diameters, thereby forming the small-diameter portion 42 and largediameter portion 43.

An externally threaded dial operating spindle or shaft 44 extends through dial ring aperture 40, door aperture 35 and the small and large diameter tube portions 42 and 43, with the inner end of spindle 44 terminating at a point spaced inwardly from the inner end of tube 41. A dial member 45 is positioned partially received within the recessed portion 38 of dial ring 36 and is provided with a hub portion 46 of slightly smaller diameter than the dial ring aperture 40 and of slightly larger diameter than the door aperture 35. Hub portion 46 is partially telescoped in the dial ring aperture 40.

Dial member 45 is provided on its outer face with the conventional operating knob 47, which is of the usual generally cylindrical knurled construction. Further, as is conventional, the dial ring 36 may have inscribed thereon one hundred equally spaced division lines 48, with each tenth of these division lines being numbered providing a dial numbering from ten to one hundred, as best seen in Fig. 4. Also, as best seen in Fig. 4, a single preferably vertically-extending mark or arrow 49 is formed inscribed on the dial ring 36 above knob 47, with this mark being utilized in conjunction with rotation of the dial for operating the combination of the lock.

An improved cam member, generally indicated at 50, is mounted on the inner end of spindle 44, including generally hollow cylindrical head and tube portions 51 and 52. Portions 51 and 52 are internally threaded and the spindle 44 is threadably received within the tube portion 52. Cam member 50 is secured on spindle 44 by an L-shaped key member 53 received in keyways formed in the cam member 50 and spindle 44, so that the head portion 51 is retained abutting the inner end of the tube 41.

Further, when thus positioned, the tube portion 52 is rotatably received within the large-diameter tube portion 43, so that tube portion 43 forms an internal bearing surface. Cam member 50 is preferably formed from a nonmetallic plastic material, such as nylon, the advantages of which, for use in the present invention, will be hereinafter described.

A compression spring 54 is positioned surrounding the hollow cylindrical portion 39 of dial ring 36 and also surrounding the hub portion 46 of dial member 45, so that oneend of said spring abuts the inner face 45a of dial member 45 and the other end of said spring abuts the recessed portion 38 of dial ring 36. Thus, dial member 45 may be selectively pressed inwardly toward the outer face 37 of the door and into the dial ring recessed portion 38, with the result that spring 54 is compressed and spindle 44 moves axially rearwardly, moving the cam member 50 rearwardly in reference to tube 41, so that cam member 50 approaches the rear cover plate 55 of case 30. Spring 54, however, normally urges the dial 45, spindle 44 and cam member 50 to their normal outward or forward position, as illustrated in Fig. 5.

A series of preferably three tumbler wheels 56, 57 and 58 is rotatably mounted on the large-diameter tube portion 43, with the forwardmost of said tumblers or tumbler 58 abutting the inner or rearward end of the case cylindrical portion 34. Thus, an outer bearing surface is formed on the tube portion 43. Tumblers 56, 57 and 58 are of conventional construction and each includes a pair of spaced outer ring disc members adjustably engaged with a hub or center member, and each is provided with registering notches or slots formed in the outer ring disc members. These notches are preferably formed at an angle to a radial line on the tumblers, as best seen in Fig. 1, for a purpose to be hereinafter described.

A pin or projection 59 is formed on the front or for ward face of cam member 50 and this pin is engageable with a preferably nylon lever 56a journalled on the tube 41, with the other side of the lever 56a being in position to abut one end of a segmental flange formed on the center member of tumbler 56. Pin 59 is only engageable with this nylon lever 56a upon rotation of cam member 50, when the cam member is in its forwardmost or normal position, as illustrated in Fig. 5, and is disengaged therefrom when the dial member 48 is pressed inwardly moving the cam member 50 to its rearward position.

Thus, a lost-motion drive is provided between the cam member 50 and the tumbler 56. A similar lost-motion drive is provided between each set of adjacent tumblers, that is to say, between tumblers 56 and 57 and between tumblers 57 and 58, and in each case, the drive includes a pin on the tumbler, a preferably nylon lever journalled on the tube 41 and a segmental flange on the next adjacent tumbler.

Further, rotation of the cam member 50 by rotating the dial member 45 causes rotation of the tumblers 56, 57 and 58 only when the cam member 50 is in its normal or forward position, and when the dial member 45 is pressed inwardly moving the cam member 50 axially to its rearward position, the driving connection between cam member 50 and the tumblers 56, 57 and 58 is interrupted, so that further rotation of cam member 50 will not cause rotation of the tumblers.

The improved cam head portion 51 is provided with an axially preferably uniformly tapered outer circumferential surface 60, which tapers downwardly forwardly, that is to say, the rearward face of portion 51 or the face thereof nearest the rear cover plate 55, is of larger diameter than the forward face or the face thereof nearest the tumbler 56. Surface 60 is provided with a continuous circumferentially extending groove 61 formed therein spaced from the rearward face of head portion 51.

A conventional laterally-extending bolt member 62 is slidably received through the side wall 63 of case 30 and is mounted for lateral reciprocation in the conventional slides or guideways 64. A laterally-extending operating lever 65 is pivotally connected to bolt member 62 by, means of the pivot screw 66.

Lever 65 includes a laterally-extending operating arm 67 and a downwardly-extending cam follower tongue 68.- Tongue 68 normally rests on and bears against the outer circumferential cam surface 60 overlying groove 61 when cam member 50 is in its normal forward position, as illus trated in Fig. l. A spring 69 is engaged over the pivot screw 66 and the operating arm 67, urging the operating arm downwardly, and consequently urging the cam follower tongue 68 against the cam member 50.

Cam follower tongue 68 has a thickness greater than the width of groove 61 formed in the cam surface 60, so that when cam 50 is in its normal forward position, tongue 68 spans the width of groove 61, with the back surface of tongue 68 or the surface thereof nearest the rear cover plate 55 preferably positioned substantially in vertical alignment with the back surface of cam member 50, as best seen in Fig. 3.

Further, the cam head portion 51 is provided with a radially-extending lever operating notch or slot 70, preferably opening forwardly of head portion 51 and radially outwardly through the cam surface 60, with notch 70 extending from the forward face of head portion 51 rearwardly to a point spaced forwardly from the cam circumferential groove 61 and the forward face of tongue 68.

Notch 70 is positioned such that when the dial member 45 is pressed inwardly toward the outer face 37 of the door, thereby moving the spindle 44 and the cam member 50 axially rearwardly toward the back cover plate 55, the cam follower tongue 68 will overlie the circumferential area within which notch 70 is formed. Thus, when cam member 50 is rotatedto a position in which notch 70 underlies tongue 68, tongue 68 may be received therein provided certain other conditions exist, as will he hereinafter described. As illustrated in Figs. 1, 3 and 6, the lower end 71 of tongue 68 is tapered both laterally and forwardly in a generally tangential plane to the outer circumferential tapered cam surface 60, so that when cam member 50 is in its normal forward position and the tongue 68 bears against the cam surface 60 spanning the groove 61 formed therein, the lower end 71 will generally follow the contour of the tapered surface 60, as illustrated in Fig. 3.

The case 30 is provided with a lever arm guide yoke, generally indicated at 72, mounted partially on the case top wall 73 and partially on the rear cover plate 55. The top wall portion 74 of yoke 72 is preferably formed of nylon and is positioned overlying the tumblers 56, 57 and 58 and overlying a portion of the cam head portion 51, so that the rearward end of yoke wall portion 74 is spaced forwardly from the rear cover plate 55. The rear cover plate portion 75 of yoke 72 is mounted on the forward or inner face of rear cover plate 55 and extends forwardly to approximately the plane of the rear face of cam member 50 and is thereby spaced rearwardly from the rearward end of wall portion 74 providing a lever operating arm guide slot 76.

Guide slot 76 is in alignment with the operating arm 67 overlying a portion of the cam follower tongue 68 and receiving a portion of the operating arm 67 therein when the cam 50 is in its normal forward position and the cam follower tongue 68 is riding on the tapered surface 60 spanning the groove 61. The width of guide slot 76 is slightly greater than the width of operating arm 67, so that the operating arm is guided in its upward and downward travel when the cam member 50 is moved between its normally forward and rearward position, with the lower rearward edge of yoke case wall portion 74 being formed in an arcuate configuration for easier entrance of operating arm 67.

A fence 77 is mounted on the rout face of the lever operating arm 67 and extends forwardly normally overlying and spaced from the tumbler 56, 57 and 58 when the cam member 50 is in its normal forward position, as illustrated in Figs. 1 and 3. When cam member 58 is moved to its rearmost position, and the notches formed in the tumblers are not aligned, fence 77 rides on and bears against the outer peripheries of the tumblers, maintaining the cam follower tongue 68 spaced upwardly from the tapered cam surface 60, and cam notch 7%, as illustrated in Fig. 10, but when the notches of the tumblers are in alignment with the fence 77, the fence may be received therein permitting the cam follower tongue 68 to be received in the cam notch 70 to withdraw the bolt 62 in a conventional manner, the operation of which will be hereinafter more fully described.

The case top wall 73 is provided with a downwardly projecting abutment portion 78, which portion prevents the lever operating arm 67 and consequently the bolt member 62 from moving laterally when the cam member 50 is in its normal forward position and the cam follower tongue 68 is riding on the tapered surface 60 spanning the groove 61, or when the cam member 50 is in its rearward position, but the fence 77 is riding on the outer peripheries of the tumblers 56, 57 and 58. The rear cover plate 55 is provided with the conventional aperture 79 formed therein so that a key used for changing combinations may be inserted therethrough without removal of the rear cover plate 55. The combination of the lock may be changed by rotating the outer ring disc members of the tumblers about the center members thereof in the conventional .manner.

A false engagement ball cage 89 is mounted on the inner or front face of the rear cover plate 55 and is provided with preferably four spaced spring-loaded or springpresscd balls 81, 82, 83 and 84 mounted therein. As illustrated in Fig. 9, each of the spring-loaded balls is mounted in the cage 80 in a conventional manner of mounting spring-loaded balls, so that each ball extend; a maximum predetermined distance from face 801: of cage and is normally resiliently urged to such extended position by a usual spring 84a. Thus, as shown in Fig. 9, ball 84 may be depressed into ball cage 80 by an outside force, until the top edge of ball 84 is in alignment with cage surface 80a, by compressing spring 84a, but ball 84 may not be urged to extend from cage surface 80a beyond a predetermined distance, as shown.

Cage 80 is formed in a generally arcuate configuration and is positioned so that the spring-loaded balls engage the cam tapered surface 60 and the groove 61 formed therein as the cam member 50 is moved between its nor mal forward and rearward positions and vice versa. Thus, the contour of the ball cage 80 and the positioning of the spring-loaded balls therein positions these balls at circumferentially spaced points along a portion of the circumference of the cam 5%.

These spring-loaded balls are further positioned in ball cage 80 at unequal distances from the front face of the rear cover plate 55, that is, axially spaced in reference to the longitudinal axis of cam member 50, so that ball 81 is nearest the front face of rear cover plate 55, ball 84 is farthest from rear cover plate 55 and balls 82 and 83 are at spaced distances therebetween. Still further, these spring-loaded balls are positioned at an axial position with reference to the longitudinal axis of cam member 50 and with the axial position of cam follower tongue 68 such that the first engagement of tongue 68 with the cam tapered surface 60, as the cam member 50 is moved from its rearward position axially toward its normal forward position, will occur at some point either during the engagement of one of these spring-loaded balls in the cam groove 61 or immediately after one of the balls has disengaged from groove 61 and before the next adjacent ball engages with groove 61.

In the particular embodiment illustrated in the drawings, the positioning of the spring-loaded balls in reference to the cam member 50 and the movement thereof, is such that upon moving the cam member axially between its rearward position and its normal forward position, the engagement of the cam follower tongue 68 with the cam tapered surface 60, occurs immediately after the third spring-loaded ball 83 has disengaged from or snapped out of the cam groove 61 and immediately prior to the engagement or snapping in of the fourth springloaded ball 84 into said groove.

It should be understood, however, that the engagement of the cam follower tongue 68, with the cam tapered surface 60, may be arranged to occur at any desired time, that is, prior to the engagement of any of the springloaded balls with the cam groove 61, simultaneous with the engagement of any one ball with said groove, intermediate the disengagement of one ball and the engagement of the next ball with said groove, or after the last ball has disengaged from said groove, without departing from the principles of the present invention.

It is preferred, however, that the engagement of the tongue with the cam tapered surface should occur simultaneous with the engagement of one of the balls with the groove or intermediate the disengagement of one ball and the engagement of the next ball with the groove. Further, in the event that the production tolerances become prohibitive or it is desired to minimize production costs, it is possible with the use of a plurality of spring-loaded balls to allow the positioning of these balls in reference to the cam tapered surface to vary over a wider range, since as described above, as long as the engagement of the cam follower tongue 68 with the cam tapered sure face 60 occurs in relatively close proximity to the engagement of any one of the spring-loaded balls with the cam groove 61, the advantages of the present invention will be provided.

In the general operation of the combination lock -illustrated in the drawings, which general operation is conventional to certain prior constructions of locks, when the lock is in locked position with the bolt member 62 extended, the notches of the tumblers 56, 57 and 58 are in misaligned position, as illustrated in Fig. 1. Further, cam member 50 is in its forward position and the cam follower tongue 68, on the operating lever 65, is resting on the tapered cam surface 60, spanning and overlying the cam groove 61. Finally, the cam follower tongue 68 retains the fence 77 spaced upwardly from the outer peripheries of the tumblers 56, 57 and 58.

The dial member 45 is turned alternately in opposite directions to set the predetermined combination of the lock by means of the knob 47 in the conventional manner. When the combination has been properly set, the notches of tumblers 56, 57 and 58 are in aligned position, with the openings of said notches underlying the fence 77.

The dial member 45 is then pressed inwardly against the pressure of spring 54, and thereby moves the spindle 44 rearwardly, moving the cam member 50 to its rearward position. When the cam is in this position, the cam pin 59 is disengaged from any driving connection between cam 50 and the first tumbler 56, so that any further rotation of dial member 45 will not rotate any of the tumblers and change their positions.

When dial member 45 is pressed inwardly, the cam follower tongue 68 moves down the tapered cam surface 60, so that when cam member 50 is in its rearward position, the cam follower tongue 68 is in circumferential alignment with cam notch 70. During this rearward movement of cam member 50, fence 77 moves downwardly into the opening portion of the notches in tumblers 56, 57 and 58, and if cam notch 70 is in radial alignment with cam follower tongue 68, the cam follower tongue will engage partially into cam notch 70, otherwise cam follower tongue 68 will rest against the tapered cam surface 60 in circumferential alignment with cam notch 7 0.

With dial member 45 retained in its inwardly-pressed position, maintaining the cam member 50 in its rearward position, the dial member 45 is rotated in a clockwise direction looking at the face of the dial member or in a counterclockwise direction looking at the rear of the case 30, as shown in Figs. 7 and 8. This rotation of dial member 45 rotates cam member 50 and if cam notch 70 is not in radial alignment with cam follower tongue 68, when cam member 50 is rotated to a position for such radial alignment between said notch and tongue, said tongue will then engage partially into said notch, in the position illustrated in Fig. 7.

Continued rotation of cam member 50 causes the cam follower tongue 68 to further engage in cam notch 70 and causes cam member 50 to move operating lever 65 and consequently bolt member 62 from locked or boltextended position to unlocked or bolt-retracted position, said unlocked position being illustrated in Fig. 8. The resiliency of spring 69 urging operating lever 65 downwardly or urging it to rotate in a counterclockwise direction, as seen in Figs. 7 and 8, around the pivot screw 66, causes the cam follower tongue 68 and the fence 77 to engage in the cam and tumbler notches, respectively, when cam member 50 is rotated to unlocked position.

Since fence 77 is mounted on the end portion of operating lever 65 and since operating lever 65 is rotating around pivot screw 66 during the unlocking operation, fence 77 must move downwardly in an arcuate path determined by the constant radial distance of fence 77 from' pivot screw 66. Thus, with the notches in tumblers 56, 57 and 58 being positioned opening and extending at an angle to a radial line of said tumblers, the fence 77 is permitted to easily and conveniently enter ,or leave said notches.

In relocking the lock, the dial member 45 is merely rotated in a counterclockwise direction, looking at the face-of said dial, .or a clockwise direction, looking-at the rear of case 30, as viewed in Figs. 7 and 8, and such row tion rotates cam member 50, causing said cam member to move operating lever 65 and bolt member 62 to the right, as seen in Figs. 7 and 8. This rotation is con tinued until cam follower tongue 68 is disengaged from cam notch 70, at which time, spring 54 urges dial member 45 and cam 50 to their normal forward positions,

present invention, to determine the combination and unlock the lock by carrying out procedures of manipulation that have been evolved, further provided that the lower longitudinal face of fence 77 is at a slight angle to the longitudinal axis of tumblers 56, 57 and 58, or that the outer peripheries of the tumblers are slightly misaligned or have different dimensions in reference to each other, Such conditions may exist in almost all combination locks that have been built in mass production due to variations in the size and assembly of parts. As before stated, these slight errors are unavoidable if a combination lock is to be mass produced, even though the most modern production equipment and controls are used.

Assuming, for purposes of description, that the lower longitudinal face of fence 77 angles slightly upwardly from its point of connection to operating arm 67 on the operating lever 65 and in reference to the longitudinal I axis of tumblers 56, 57 and 58, a person attempting to manipulate the lock would start by pressing the dial member 45 inwardly causing the cam member 50 to move to its rearward position. The manipulator would then allow the dial member 45 to move outwardly and by use of the sense of feel and conventional depth gauges, determine at what point in the outward movement of dial member 45 the cam follower tongue 68 engaged with the tapered cam surface 60.

The manipulator would then rotate the dial member 45 predetermined increments repeating the above measuring operation at each position until a point was found when the cam follower tongue 68 engaged the tapered cam surface 60 at a point earlier than the first measurement taken, that is, when the cam follower tongue 68 engaged at a lower point on the tapered cam surface 60. This occurrence would indicate that at that position, the fence 77 is engaged with the notch of tumbler 56, which engagement would permit the fence 77 and thus, the cam follower tongue 68 to move downwardly a greater distance when the cam member 50 is moved to its rearward position by pressing in dial member 45. In this way, the position of the notch in tumbler 56 would be determined.

It is apparent that, with fence 77 angling slightly upwardly in reference to the longitudinal axis of tumblers 56, 57 and 58, when the notches of both tumblers 56 and 57 are in alignment with fence 77, the cam follower tongue 68 would be permitted to move downwardly a still greater distance when the cam member 50 is moved to its rearward position by pressing in the dial member 45. Further this occurrence could be determined by a manipulator by measuring the point at which the cam follower tongue 68 engaged the tapered cam surface 60, as the dial member 45 was permitted to move outwardly moving the cam member 50 toward its forward position. Thus, in this manner, the proper positioning of each of the tumblers 56, 57 and 58 for alignment of the notches thereof with fence 77 could be determined, and a skilled manipulator can ultimately manipulate the lock to place it in unlocked position.

However, the improvements of the present invention hide or mask the point at which the cam follower tongue 68 engages the tapered cam surface 60 when cam member 50 is moved from its rearward to its normal forward position; This masking is accomplished by the arrange ment, or construction, configuration and composition of cam member 50, the false engagement means, and the guide yoke 72. In the present embodiment the false engagement means is in the form of ball cage 80, and springloaded, balls 81, 82, 83 and 84 and the yoke 72 guide the upward and downward movement of operating arm 65 and consequently cam follower tongue 68.

It should be understood that the false engagement means can include members other than balls mounted in relation to the dial member 45, spindle 44 or cam member 50, which produce a definite feel of engagement when the cam member 50 is moved from its rearward to its normal forward position, and which mask or make it impossible to identify the point at which the cam follower tongue 68 engages the cam member 50, thereby making manipulation of the lock impossible. It is preferred, however, that the false engagement means he in the form of the spring-loaded balls 81, 82, 83 and 84 mounted in the ball cage 80 and bearing against the tapered cam surface 60, as illustrated in the drawings. One of the principal advantages of using spring-loaded balls is that it is relatively easy to maintain close tolerances in the positioning of these balls in reference to the cam member 50, both radially and longitudinally of the cam member, in mass production, thereby resulting in reduced production costs as compared to the use of other types of false engagement means.

Referring to Figs. through 27, the positions of the various parts of the lock are shown in sequence as the dial member 45 and consequently the cam member 50 are moved from their rearward positions to their normal forward positions. Certain pertinent positions are shown in each case in a view looking at the back of case 38 with the rear cover plate 55 broken away, in section showing the position of the fence 77 in relation to the outer peripheries of the tumblers 56, 57 and 58, cam follower tongue 68, earn 50 and various sections through the ball cage 80, and a diagrammatic View showing the relation of the outer peripheries of the tumblers 56, 57 and 58, fence 77 and cam follower tongue 68, the cam member 54) and the spring-loaded balls 81, 82, 83 and 84.

.As illustrated in Figs. 10, 11 and 12, the dial member 45 has been pressed inwardly placing the cam member 50 at its maximum rearward position, so that the fence 77 is resting on the outer peripheries of the tumblers 56, 57 and 58, thereby retaining the cam follower tongue 68 spaced upwardly from the tapered cam surface 60 and overlying the circumferential area of cam 50 having the cam notch 70 formed therein. Further, the first or the rearmost spring-loaded ball 81 is in a position just engaging the tapered cam surface 60 forwardly of the cam groove 61, while the other spring-loaded balls 82, 83 and 84 are forwardly of ball 81 and are therefore not as yet engaged with cam member 59.

In Figs. 13 and 14, the cam member 59 is shown moved forwardly to a point where the first or rearmost spring-loaded ball 81 has snapped into or engaged with the cam groove 61. The fence 77 is still resting on the outer peripheries of tumblers 56, 57 and 58 retaining the cam follower tongue 68 spaced upwardly from the tapered cam surface 60. The second spring-loaded ball 82 in this position has started to engage the tapered cam surface 60, while the third and fourth spring-loaded balls 83 and 84 are still spaced forwardly and not in engagement with said tapered cam surface.

As shown in Figs. 15, 16 and 17, the cam member 50 has been moved forwardly until the second spring-loaded ball 82 has snapped" into or engaged the cam groove 61 and the first spring-loaded ball 81 has moved out of engagement with cam groove 61 and is resting on the tapered cam surface 60 rearwardly of said cam groove. The fence 77 is still resting on the outer peripheries of the. tumblers 56, 57 and 58 retaining the cam follower tongue '68 spacedupwardlyfrom the tapered cam sur- 1 2 face 60, while, the third spring-loaded ball 83* is just. engaging with the tapered cam surface 60 forwardly ofthe cam groove 61 and the fourth spring-loaded ball 84 is still out of engagement with any portion of cam 50.

As cam 50 is moved forwardly, another increment, as illustrated in Figs. 18, 19 and 20, the third spring-loaded ball 83 has snapped into or is engaged in the cam groove 61, while the first and second spring-loaded balls 81 and 82 are riding on the tapered cam surface 60 rear wardly of said groove. Further, fence 77 is still resting on the outer peripheries of tumblers 56, 57 and 58 retaining the cam follower tongue 68 spaced upwardly from the tapered cam surface 60, with the fourth spring-loaded ball 84 just engaged with the tapered cam surface 60 forwardly of the cam groove 61. I

As illustrated in Figs. 21, 22 and 23, the cam member 58 has been moved forwardly until the third springloaded ball 83 has begun to move out of cam groove 61 and the first and second spring-loaded balls 81 and 82 are bearing against the tapered cam surface 60 rear wardly of cam groove 61, while the fourth spring-loaded ball 84 has not as yet snapped into or fully engaged with cam groove 61. In this position, fence 77 is still resting on the outer peripheries of tumblers 56, 57 and 58, but the cam follower tongue 68 has just engaged the tapered cam surface, 60 at a point forwardly of and partially overlying the tapered cam groove 61.

As cam member 50 is moved further forwardly, as illustrated in Figs. 24, 25 and 26, the fourth spring-loaded ball 84 snaps into or engages with cam groove 61, while the first three spring-loaded balls 81, 82 and 83 are bearing against, the tapered cam surface 60 rearwardly of cam groove 61. Further, in this position, the cam follower tongue 68 has begun to move upwardly on the tapered cam surface 68 and is resting thereon, thereby raising the fence 77 from the outer peripheries of turnblers 56, 5'7 and 58.

Finally, as illustrated in Figs. 1, 3 and 27, earn member 50 has moved to its normal forward position, with cam follower tongue 68 resting on the tapered cam surface 60 spanning the cam groove 61 and thereby retaining fence 77 spaced upwardly from the outer peripheries of tumblers 56, 57 and 58. The second, third and fourth spring-loaded balls 82, 83 and 84 are engaged with the tapered cam surface 60 rearwardly of cam groove 61, with the first or rearmost spring-loaded ball 81 engaged slightly over the back or rearward edge of cam member 50.

Thus, the false engagement means, shown in the present embodiment of the form of spring-loaded balls 81, 82, 83 and 84 mounted in ball cage 88, prevents an unau thorized person attempting to manipulate the lock from determining when the cam follower tongue 68 engages the tapered cam surface 60, and therefore such manipulator is prevented from determining the position of the notches in the tumblers 56, 57 and 58. Although, as before stated, other forms of false engagement means may be used engageable with any of the dial member 45, spindle 44 or cam member 50, it is preferred to use resilient means such as the spring-loaded balls 81, 82, 83 and 84 in combination with a cam groove 61 formed in a tapered cam surface 60, since not only do these spring-loadedballs create a definite feel of engagement when they engage the tapered cam surface 60 and snap into cam groove 61, but also this snapping of these spring-loaded balls into the cam groove causes a definite jump in the inward movement of cam member 50, spindle 44 and dial member 45, so that it is impossible to accurately measure definite distances of partial inward movement of the dial member.

The guide yoke 72. serves the purpose of guiding operating lever 65 in its upward and downward movement in a definite path and consequently the cam follower tongue 68, is so guided. The spring-loaded balls 81, 82, 83 and 84 thus may be set .at predetermined positions in rela,-.

tion to cam follower tongue 68, so that the engagement of cam follower tongue 68 with the tapered cam surface 60 will always occur at some point intermediate the engagement of adjacent spring-loaded balls or simultaneous with the engagement of a particular spring-loaded ball. In any such event, the positioning of the spring-loaded balls in relation to the upward and downward movement of the cam follower tongue may be set at a predetermined relationship so that the cam follower tongue will engage the tapered cam surface at some point intermediate the engagement of the first spring-loaded ball and the disengagement of the last spring-loaded ball with the cam groove, despite the positioning of the tumbler notches, the angularity of the fence, and the uniformity or nonuniformity of the outer peripheries of the tumblers. The wall portion 74 of guide yoke 72 is preferably formed from a non-metallic plastic material such as nylon, to reduce wear and reduce the noise of operation while at the same time the self-lubricating qualities of nylon are utilized.

The cam member 50 is also preferably formed of a non-metallic plastic material, such as nylon, again because of the wearing and also the sound and feel deadening qualities of nylon. Although metallic spring-loaded balls 81,82, 83 and 84 are used snapping in and out of the cam groove 61, and although the cam follower tongue 68'rests on the tapered cam surface 60 during the' se'tting of the combination of the lock, a nylon cam, because 'of its excellent wearing qualities, will far outlast the" usefulness of the metallic parts in the lock. Also, withthe' use of a nylon cam member 50, the engagement of' anything with the tapered cam surface 60, such as the metal cam follower tongue 68, is much more difficult to discern, due to the sound and feel deadening qualities of nylon. I

Although it is preferred that the tapered cam surface 60 of'cam member 50 have a uniform taper of about the degree of taper shown, it should be understood that other degrees of taper and non-uniform tapers may be used without departing from the principles of the present invention.

Finally, it should be understood that although forming the-cam member 50 from material, such as nylon, provides certain advantages as pointed out above, this cam member may be formed of other materials, including metal, and many of the advantages and improvements of the present invention including manipulation-proofness would still be provided.

In the foregoing description, certain terms have been usedfor brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example and the scope of the present invention is not limited to the exact details of construction shown.

' Having now described the invention, the construction, operation and use of a preferred embodiment thereof, the advantageous new and useful results obtained thereby, the new and useful construction and reasonable mechanical equivalents thereof, obvious to those skilled in the art, are set forth in the appended claims.

, We claim:

1. In a combination lock of the kind having a housing, a locking member movably mounted on said housing, an elongated, manually-rotatable, dial shaft extending into 'said housing, longitudinally movable between normal and second positions, a'disk-like cam secured to said shaft within 'saidhousing for rotation and longitudinal movement with said shaft, said cam having a gate in the periphery thereof, a movable fence associated with said locking member for controlling movement thereof, said fence being 'formedto initially engage the cam during movement of'the earn from said second to normal position and to interlock with the gate of said cam when the latter is in said second longitudinal position and is rotated to a predetermined position with respect to said fence, whereby continued rotation of said cam in one direction shifts said fence and said locking member to an unlocked position, the walls defining said gate being formed to move said fence to a position released from said cam when said cam is rotated in the opposite direction, a plurality of tumblers interconnected by lost motion driving connections and being operably mounted within said housing and about the axis of said shaft, and a lost motion driving connection between said cam and one of said tumblers, said tumblers blocking movement of said fence from said released position except when they are shifted to a predetermined set position in which said fence is permitted to move to a position interlocked with said cam; the improvement of which comprises peripheral groove means formed circumferentially in the cam, and resilient means spaced longitudinally with respect to the dial shaft and circumferentially with respect to the cam respectively sequentially engaging the cam and cam groove means as the dial shaft is moved longitudinally from second to normal position thereby indicating false engagements with the cam as the cam carried by the dial shaft is shifted longitudinally from said second to normal position which masks the initial engagement of the fence with the cam.

2. In a combination lock of the kind having a case, a longitudinally movable spindle rotatably mounted extending partially into the case, dial means mounted on the spindle outside of the case, generally cylindrical cam means having a drive notch formed therein mounted on the spindle within the case, said dial and cam means being rotatable and longitudinally movable with the spindle, a series of tumbler wheels having outwardly opening notches formed therein rotatably mounted on the spindle and interconnected in lost motion driving connection to each other and to the cam means when the spindle is in its normal position of longitudinal movement, said cam means driving connection being interrupted when the spindle is moved from its normal to a second longitudinal position, movable bolt means having a cam follower tongue and a fence operably connected thereto, the fence being received in the tumbler wheel notches when said notches are aligned at a predetermined position and permitting the cam follower tongue to engage the cam means drive notch when the spindle is moved from its normal to said second longitudinal position and rotated thereby retracting the bolt means, the fence resting on the'tumbler wheels maintaining the cam follower tongue disengaged from the cam means when the tumbler wheel slots are not aligned at said predetermined position and when the spindle is then moved from its normal to said second longitudinal position, and the cam follower tongue resting on the cam means and maintaining the fence spaced from the tumbler Wheels when the spindle is in its normal position; the improvements including a tapered outer peripheral surface formed on the cam means, the cam follower tongue being engaged by said tapered surface when the spindle and cam means are moved from said second longitudinal position to normal position and when the tumbler wheel notches are not aligned at said predetermined position, the cam follower tongue initially engaging said tapered surface after partial movement of the cam means from second to normal position and remaining engaged with said surface after such initial engagement and during the remaining movement of the cam means to normal position, false engagement means including engageable elements mounted on the lock independent of the cam follower tongue and independent of said engagement of the cam follower tongue with the cam means, certain of said false engagement elements being operably connected to and movable with the movable spindle, and at least certain of said engageable elements moving to positions of engagement with each other normally at a different time than said engagement of the cam follower tongue with the cam means upon longitudinal movement of the spindle, Whereby separate false engagement indications are given establishing confusion with the indication of said engagement of the cam follower tongue with the cam means.

3. The combination lock construction defined in claim 2 in which the false engagement means includes elements mounted for engagement with the cam means normally at a different time than said engagement of the cam follower tongue with the cam means upon longitudinal movement of the spindle and cam means.

4. The combination lock construction defined in claim 2 in which the false engagement means includes resilient means mounted for engagement with the cam means normally at a different time than said engagement of the cam follower tongue with the cam means upon longitudinal movement of the spindle and cam means.

5. In a combination lock of the kind having a case, a longitudinally movable spindle rotatably mounted extending partially into the case, dial means mounted on the spindle outside of the case, generally cylindrical cam means having a drive notch formed therein mounted on the spindle within the case, said dial and cam means being rotatable and longitudinally movable with the spindle, a series of tumbler wheels having outwardly opening notches formed therein rotatably mounted on the spindle and interconnected in lost motion driving connection to each other and to the cam means when the spindle is in its normal position of longitudinal movement, said cam means driving connection being interrupted when the spindle is moved from its normal to a second longitudinal position, movable bolt means having a cam follower tongue and a fence operably connected thereto, the fence being received in the tumbler wheel notches when said notches are aligned at a predetermined position and permitting the cam follower tongue to engage the cam means drive notch when the spindle is moved from its normal to said second longitudinal position and rotated thereby retracting the bolt means, the fence resting on the tumbler wheels maintaining the cam follower tongue disengaged from the cam means when the tumbler wheel slots are not aligned at said predetermined position and when the spindle is then moved from its normal to said second longitudinal position, and the cam follower tongue resting on the cam means and maintaining the fence spaced from the tumbler Wheels when the spindle is in its normal position; the improvements including a tapered outer peripheral surface formed on the cam means, the cam follower tongue-being engaged by said tapered surface when the spindle and cam means are moved from said second longitudinal position to normal position and when the tumbler wheel notches are not aligned at said predetermined position, the cam follower tongue initially engaging said tapered surface after partial movement of the cam means from second to normal position and remaining engaged with said surface after such initial engagement and during the remaining movement of the cam means to normal position, and false engagement means independent of the cam follower tongue including a series of longitudinally spaced resiliently pressed members engageable with the cam means at longitudinally spaced in-. tervals as the cam means is moved from its second longitudinal position to its normal position.

6. The combination lock construction as defined in claim 5 in which the resiliently pressed members are spring-pressed balls mounted on the case.

i 7. In a combination lock of the kind having a case, a longitudinally movable spindle rotatably mounted extending partially into the case, dial means mounted on the spindle outside of the case, generally cylindrical cam means having a drive notch formed therein mounted on the spindle within the case, said dial and cam means being rotatable and longitudinally movable with the spindle, a series of tumbler wheels having outwardly opening notches formed therein rotatably mounted on the spindle and interconnected in lost motion driving connection to each other and to the cam means when the spindle is in its normal position of longitudinal movement, said cam means driving connection being interrupted when the spindle is moved from its normal to a second longitudinal position, movable bolt means having a cam follower tongue and a fence operably connected thereto, the fence being received in the tumbler wheel notches when said notches are aligned at a predetermined position and permitting the cam follower tongue to engage the cam means drive notch when the spindle is moved from its normal to said second longitudinalposition and rotated thereby retracting the bolt means, the fence resting on the tumbler wheels maintaining the cam follower tongue disengaged from the cam means when the tumbler wheel slots are not aligned at said predetermined position and when the spindle is then moved from its normal to said second longitudinal position, and the cam follower tongue resting on the cam means and maintaining the fence spaced from the tumbler wheels when the spindle is in its normal sition; the improvements including a tapered outer periph-,- eral surface formed on the cam means, the cam follower tongue being engaged by said tapered surface when the spindle and cam means are moved from said second longitudinal position to normal position and when the tumbler wheel notches are not aligned at said predetermined po,- sition, the cam follower tongue initially engaging said tapered Surface after partial movement of the cam means from second to normal position and remaining engaged with said surface after such initial engagement and during the remaining movement of the cam means to normal sition, false engagement means independent of the cam follower tongue and independent of said engagement of the cam follower tongue with the cam means, said false engagement means including a circumferentially extending groove formed in the tapered cam surface of the cam spaced axially from the ends of the cam means and opens ing radially outwardly of the tapered outer peripheral surface, and said false engagement means also including re silient means mounted for engagement with the groove and tapered cam surface as the cam means is moved from its second longitudinal position to its normal position, whereby the false engagement means provides separate engagement indications establishing confusion with the indication of engagement of the cam follower tongue with the cam means.

8. In a combination lock of the kind having a case, a longitudinally movable spindle rotatably mounted ens tending partially into the case, dial means mounted on the spindle outside of the case, generally cylindrical cam means having a drive notch formed therein mounted on the spindle within the case, said dial and cam means being rotatable and longitudinally movable with the spindle, a series of tumbler wheels having outwardly opening notches formed therein rotatably mounted on the spindle and interconnected in lost motion driving connection to each other and to the cam means when the spindle is in its normal position of longitudinal movement, said cam means driving connection being interrupted when the spindle is moved from its normal to a second longitudinal position, movable bolt means having a cam follower tongue and a fence operably connected thereto, the fence being received in the tumbler wheel notches when said notches are aligned at a predetermined position and permitting the cam follower tongue to engage the cam means drive notch when the spindle is moved from its normal to said second longitudinal positionand rotated thereby retracting the bolt means, the fence resting on the tumbler wheels maintaining the cam follower tongue disengaged from the cam means when the tumbler wheel slots are not aligned at said predetermined position and when the spindle is then moved from its normal to said second longitudinal position, and the cam follower tongue resting on the cam means and maintaining the fence spaced from the tumbler wheels when the spindle is in its normal position; the improvements including a tapered outer peripheral surface formed on the cam means, the cam follower tongue being engaged by said tapered surface when the spindle and cam means are moved from said second longitudinal position to normal position and when the tumbler wheel notches are not aligned at said predetermined position, the cam follower tongue initially engaging said tapered surface after partial movement of the cam means from second to normal ,position, and remaining engaged with said surface after such initial engagement and during the remaining movement of. the cam means to normal position, false engagementmeans independent of the cam follower tongue and independent of said engagement of the cam follower tonguewith the cam means, said false engagement means including a circumferentially extending groove formed-in the tapered cam surface of the camspaced axially from the ends of the cam means and opening radially outwardly of the tapered outer peripheral surface, and said false engagement means also including a series of longitudinally spaced springpressed balls engageable with the cam groove and tapered cam surface at longitudinally spaced intervals as the cam means is moved from its second longitudinal position to its normal position.

9. In a combination lock of the kind having a case, a longitudinally movable spindle rotatably mounted extending partially into the case, dial means mounted on the spindle outside of the case, generally cylindrical cam means having a drive notch formed therein mounted on the spindle within the case, said dial and cam means being rotatable and longitudinally movable with the spindle, a series of tumbler wheels having outwardly opening notches formed therein rotatably mounted on the spindle and interconnected in lost motion driving connection to each other and to the cam means when the spindle is in its normal position of longitudinal movement, said cam means driving connection being interrupted when the spindle is moved from its normal to a second longitudinal position, movable bolt means having a cam follower tongue and a fence operably connected thereto, the fence being received in the tumbler wheel notches when said notches are aligned at a predetermined position and permitting the cam follower tongue to engage the cam me'ans drive notch when the spindle is moved from its normal to said second longitudinal position and rotated thereby retracting the bolt means, the fence resting on the tumbler wheels maintaining the cam follower tongue disengaged from the cam means when the tumbler 'wheel slots are not aligned at said predetermined position and whenthe spindle is then moved from its normal to said second longitudinal position, and the cam follower tongue resting on the cam means and maintaining the fence spaced from the tumbler wheels when the spindle is in its normal position; the

improvements including a tapered outer peripheral surface formed on the cam means, the cam follower tongue being engaged by said tapered surface when the spindle and cam means are moved from said second longitudinal position to normal position and when the tumbler wheel notches are not aligned at said predetermined position, the cam follower tongue initially engaging said tapered surface after partial movement of the cam means from second to normal position and remaining engaged with said surface after such initial engagement and during the remaining movement of the cam means to normal position, false engagement means independent of the cam follower tongue including a series of longitudinally spaced spring-pressed balls mounted on the case and engageable with the cam means at longitudinally spaced intervals as the cam means is moved from its second longitudinal position to its normal position for masking said initial engagement of the cam follower tongue with :18 the cam means, and guide means mounted on theme and engageable with the cam follower tongue for requiring movement of the tongue in a predetermined plane perpendicular to the axis of the spindle.

10. In a combination lock of the kind having a case, a longitudinally movable spindle rotatably mounted extending partially into the case, dial means mounted on the spindle outside of the case, generally cylindrical cam means having a drive notch formed therein mounted on the spindle within the case, said dial and cam means being rotatable and longitudinally movable with the spindle, a series of tumbler wheels having outwardly opening notches formed therein rotatably mounted on the spindle and interconnected in lost motion driving con-' nection to each other and to the cam means when the spindle is in its normal position of longitudinal movement, said cam means driving connection being interrupted when the spindle is moved from its normal to a second longitudinal position, movable bolt means having a cam follower tongue and a fence operably connected thereto, the fence being received in the tumbler wheel notches when said notches are aligned at a predeter-' mined position and permitting the cam follower tongue to engage the cam means drive notch when the spindle is moved from its normal to said second longitudinal position and rotated thereby retracting the bolt means, the fence resting on the tumbler wheels maintaining the cam follower tongue disengaged from the cam means when the tumbler wheel slots are not aligned at said predetermined position and when the spindle is then moved from its normal to said second longitudinal position, and the cam follower tongue resting on the cam means and maintaining the fence spaced from the tumbler wheels when the spindle is in its normal position; the improvements including a tapered outer peripheral surface formed on the cam means, the cam follower tongue being engaged by said tapered surface when the spindle and cam means are moved from said second longitudinal position to normal position and when the tumbler wheel notches are not aligned at said predetermined position, the cam follower tongue initially engaging said tapered surface after partial movement of the cam means from second to normal position and remaining engaged with said surface after such initial engagement and during the remaining movement of the cam means to normal position, the cam means tapered surface being uniformly tapered and being formed of nylon, false engagement means independent of the cam follower tongue including a circumferentially extending groove formed in the cam means tapered surface spaced axially from the ends of the cam means and opening radially outwardly of the tapered outer peripheral surface, the cam follower tongue being formed of metal, a guide yoke engageable with the cam follower tongue and having a guide slot formed therein requiring movement of the tongue in a predetermined plane perpendicular to the axis of the spindle, at

least one of the surfaces of said guide slot being formed" of nylon, and said false engagement means also including a series of longitudinally spaced spring-pressed balls engageable with the cam groove and tapered camsurface at longitudinally spaced intervals as the cam means is moved from its second longitudinal position to its normal position to mask the initial engagement of the cam follower tongue with the cam means.

11. In a combination lock of the kind having a case, a longitudinally movable spindle rotatably mounted extending partially into the case, dial means mounted on the spindle outside of the case, generally cylindrical cam means having a drive notch formed therein mounted on the spindle within the case, said dial and cam means being rotatable and longitudinally movable with the spindle, a series of tumbler wheels having outwardly opening notches formed therein rotatably mounted on the spindle and interconnected in lost motion driving con- 19 motion to each other and to the cam means when the spindle is in its normal position of longitudinal movement, said cam means driving connection being interrupted when the spindle is moved from its normal to a second longitudinal position, movable bolt means having acam follower tongue and a fence operably connected thereto, the fence being received in the tumbler wheel notches when said notches are aligned at a predetermined position and permitting the cam follower tongue to engage the cam means drive notch when the spindle is moved from its normal to said second longitudinal position and rotated thereby retracting the bolt means, the fence resting on the tumbler wheels maintaining the cam follower tongue disengaged from the cam means when the tumbler wheel slots are not aligned at said predetermined position and when the spindle is then moved from its normal to said second longitudinal position, and the cam follower tongue resting on the cam means and maintaining the fence spaced from the tumbler wheels when the spindle is in its normal position; i

the improvements including a tapered outer peripheral surface formed on the cam means, the cam follower tongue being engaged by said tapered surface when the spindle and cam means are moved from said second longitudinal position to normal position and when the tumbler. wheel notches are not aligned at said predetermined position, the cam follower tongue initially engaging said tapered surface after partial movement of the cam means from second to normal position and remaining engaged with said surface after such initial engagement and during the remaining movement of the cam means to normal position, false engagement means including engageable elements mounted on the lock independent of the cam follower tongue and independent of said engagement of the cam follower tongue with the cam means, certain of said false engagement elements being operably connected to and movable with the movable spindle, and at least certain of said engageable elements moving to positions of engagement with each other normally at a different time than said engagement of the cam follower tongue with the cam means upon longitudinal movement of the spindle, whereby separate false engagement indications are given establishing confusion with the indication of saidengagement of the cam follower tongue with the cam means, and spaced guide means mounted on the case and engageable with the cam follower tongue for requireing movement of the tongue in a predetermined plane perpendicular to the axis of the spindle.

12. The combination lock construction defined in claim 11 in which the spaced guide means includes a guide yoke mounted on the case and having a guide slot formed therein engageable with the cam follower tongue.

13. In a combination lock of the kind having a case, a longitudinally movable spindle rotatably mounted extending partially into the case, dial means mounted on the spindle outside of the case, generally cylindrical cam means having a drive notch formed therein mounted on the spindle within the case, said dial and cam means being rotatable and longitudinally movable with the spindle, a series of tumbler wheels having outwardly opening notches formed therein rotatably mounted on the spindle and interconnected in lost motion driving connection to each other and to the cam means when the spindle is in its normal position of longitudinal movement, said cam means driving connection being interrupted when the spindle is moved from its normal to a; second longitudinal position, movable bolt means having a cam follower tongue and a fence operably connected thereto, the fence being re ceived in the tumbler wheel notches when said notches are aligned at a predetermined position and permitting the cam follower tongue to engage the cam means drive notch When the spindle is moved from its normal to said second longitudinal position and rotated thereby retracting the bolt means, the fence resting on the tumbler wheels maintaining the cam follower tongue disengaged from the cam means when the tumbler wheel slots are not aligned at said predetermined position and when the spindle is then moved from its normal to said second longitudinal position, and the cam follower tongue resting on the cam means and maintaining the fence spaced from the tumbler wheels when the spindle is in its normal position; the improvements including a tapered outer peripheral surface formed on the cam means, the cam follower tongue being engaged by said tapered surface when the spindle and cam means are moved from said second longitudinal position to normal position and when the tumbler Wheel notches are not aligned at said predetermined position, the cam follower tongue initially engaging said tapered surface after partial movement of the cam means from second to normal position and remaining engaged with said surface after such initial engagement and during the remaining movement of the cam means to normal position, the cam means being formed of nylon, false engagement means independent of the cam follower tongue and independent of said engagement of the cam follower tongue with the cam means, said false engagement means including a circumferentially extending groove formed in the cam means tapered surface spaced axially from the ends of the cam and opening radially outwardly of the tapered outer peripheral surface, the cam follower tongue being formed of metal, said false engagement means also including resilient means mounted for engagement with the cam groove and surface normally at a different time than said engagement of the cam follower tongue with the cam means upon longitudinal movement of the spindle, whereby separate false engagement indications are given cstablishing confusion with the indication of said engagement of the cam follower tongue with the cam means, and guide means engagea'ble with the cam follower tongue for requiring movement of the tongue in a predetermined plane perpendicular to the axis of the spindle.

References Cited in the file of this patent UNITED STATES PATENTS 79,388 Pillard June 30, 1868 237,950 Bernhardt Feb. 22, 1881 304,203 Joerden Aug. 26, 1884 550,655 Stone Dec. 3, 1895 1,956,304 Abbott et al Apr. 24, 1934 2,775,113 Behrens Dec. 25, 1956 2,775,115 Bremer Dec. 25, 1956

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