Patent Publication Number: US-6209368-B1

Title: Combination lock

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a combination lock that may prevent inadvertent change in the unlocking code. The present invention also relates to a combination lock that has a better rotational positioning effect for each number wheel and that provides a sound for indicating rotation of each number wheel. 
     2. Description of the Related Art 
     Combination locks provide a convenient tool for users, as keys are not necessary. Traditional combination locks have fixed unlocking code when manufactured and are thus easily unlocked by unauthorized individuals. FIG. 6 of the drawings illustrates a conventional lock allowing change in the unlocking code. The lock has a male lock body  1 ′ and a female lock body  2 ′. The female lock body  2 ′ includes a recessed chamber  21 ′ in a first side thereof and a groove  22 ′ in a second side thereof. A stem  23 ′ extends from the first side of the female lock body  2 ′ for mounting an elastic element  24 ′, a number of slide sleeves  25 ′, a number of positioning resilient plates  26 ′, a number of retainer plates  27 ′, a number of number wheels  28 ′, a control slide sleeves  29 ′, and an end cap  20 ′. Each retainer plate  27 ′ has a slit  271 ′ and a number of teeth  272 ′ on a side thereof. Each number wheel  28 ′ has a number of annularly disposed engaging grooves  281 ′. 
     FIG. 7 illustrates a sectional view of the combination lock in FIG.  6 . When change in the unlocking code is required, the control sleeve  29 ′ is actuated to move the retainer plates  27 ′ and slide sleeves  25 . The teeth  272 ′ on each retainer plate  27 ′ disengage from the engaging grooves  281 ′ of the associated number wheel  28 ′, thereby allowing adjustment in the unlocking code by rotating the number wheels  28 ′. 
     Nevertheless, the above-mentioned adjustment can be proceeded even though the combination lock is in a locked status (i.e., the slits  271 ′ of the retainer plates  27 ′ are not aligned with each other). As a result, the user may not know the correct new unlocking code. In addition, the adjustment is inconvenient to the user, as the user has to exert a continuous force to the control sleeve  29 ′ until the new unlocking code is set. In addition, the teeth  272 ′ of each retainer plate  27 ′ may be not completely disengaged from the engaging holes  281 ′ of the associated number wheel  28 ′ and thus result in malfunction of the combination lock, as the correct unlocking code cannot be known. Assembly of the combination lock is time-consuming and inconvenient, as a slide sleeve  25 ′, a positioning resilient plate  26 ′, and a retainer plate  27 ′ are required for each number wheel  28 ′. 
     FIGS. 8 and 9 of the drawings illustrate a positioning plate  3 ′ for a combination lock. The positioning plate  3 ′ includes a recessed section  31 ′ and a channel  32 ′ for holding an elastic element  33 ′ having an end  331 ′ that will produce a sound when impinged by an inner periphery of an associated number wheel  4 ′. It is, nevertheless, found that the elastic element  33 ′ is apt to be disengaged from the positioning plate  3 ′. 
     The present invention is intended to provide a combination lock that mitigates and/or obviates the above problems. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to provide a combination lock to prevent inadvertent change in the unlocking code. 
     It is another object of the present invention to a provide combination lock that has a better rotational positioning effect for each number wheel. 
     It is a further object of the present invention to provide a combination lock that provides a sound for indicating rotation of each number wheel. 
     In accordance with a first aspect of the invention, a combination lock comprises: 
     a male lock body including a rod with a plurality of longitudinally spaced teeth formed thereon; and 
     a female lock body including: 
     a column having a longitudinal slit for releasably receiving the rod of the male lock body, the column including a plurality of pairs of protrusions on two lateral sides thereof, 
     a plurality of sleeves mounted around the column, each said sleeve including a central hole with a notched section through which the rod of the male lock body extends, a periphery defining the central hole of each said sleeve including a pair of grooves for releasably engaging with one of the pairs of protrusions of the column, 
     a plurality of retainer plates mounted around the column, each said retainer plate including a central hole with a notched section through which the rod of the male lock body extends, a periphery defining the central hole of each said retainer plate including a pair of grooves for releasably engaging with one of the pairs of protrusions of the column, 
     a plurality of number wheels mounted around the column, each said retainer plate being releasably engaged with an associated said number wheel to rotate therewith, 
     an elastic element mounted around an end of the column for biasing each said retainer plate to engage with the associated number wheel to rotate therewith; and 
     means for actuating each said retainer plate to disengage from the associated number wheel for allowing a change in unlocking code for the combination lock, the actuating means being operable only when the combination lock is in an unlocked status in which the grooves of each said retainer plate align with the protrusions of the column. 
     In accordance with a second aspect of the invention, a combination lock comprises: 
     a male lock body including a rod with a plurality of longitudinally spaced teeth formed thereon; and 
     a female lock body including: 
     a column having a longitudinal slit for releasably receiving the rod of the male lock body, the column including an engaging section, 
     a plurality of resilient sleeves mounted around the column, each said sleeve including a central hole through which the rod of the male lock body extends, 
     a plurality of retainer plates mounted around the column, each said retainer plate including a central hole through which the rod of the male lock body extends, 
     a plurality of number wheels mounted around the column, each said retainer plate being releasably engaged with an associated said number wheel to rotate therewith, 
     an elastic element mounted around an end of the column for biasing each said retainer plate to engage with the associated number wheel to rotate therewith; 
     an actuating ring mounted around the column and including a central hole with a notched section through which the rod of the male lock body extends, a periphery defining the central hole of the actuating ring including a recessed section for engaging with the engaging section of the column to thereby prevent rotation of the actuating ring, the actuating ring further including a push section on a side thereof, the push section bearing against an adjacent said retainer plate, the actuating ring further including a projection formed on the other side thereof, and 
     a turn cap rotatably mounted around the column, the turn cap including a central hole with a notched section through which the rod of the male lock body extends, a periphery defining the central hole of the turn cap including an inclined slide groove having two recessed ends for releasably engaging with the projection of the actuating ring, thereby retaining the actuating ring in place, the projection of the actuating ring being slidable along the inclined slide groove upon rotation of the turn cap such that the actuating ring moves longitudinally to actuate the retainer plates to disengage from the number wheels, thereby allowing change in unlocking code of the combination lock. 
     A stopping portion may be formed adjacent to one of the recessed ends of the inclined guide groove. 
     In accordance with a third aspect of the invention, a combination lock comprises: 
     a male lock body including a rod with a plurality of longitudinally spaced teeth formed thereon; and 
     a female lock body including: 
     a column having a longitudinal slit for releasably receiving the rod of the male lock body, the column further including an engaging section, 
     a plurality of resilient sleeves mounted around the column, each said sleeve including a central hole through which the rod of the male lock body extends, a periphery defining the central hole of one of said sleeves including a recessed section for engaging with the engaging section of the column, each said sleeve further including a bulge on an outer periphery thereof, and 
     a plurality of number wheels mounted around the column, each said number wheel receiving an associated said sleeve therein, 
     whereby the bulge of each said sleeve generates a sound when an associated said number wheel is rotated. 
     The bulge may further include an opening therein. 
     Each number lock further includes a compartment with an inner periphery for receiving the associated said sleeve. The inner periphery includes a plurality of alternatively disposed convex portions and retaining grooves, wherein the bulge is releasably retained in one of the retaining grooves. 
     Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a combination lock in accordance with the present invention; 
     FIG. 2 is a partial perspective view of the combination lock in accordance with the present invention; 
     FIG. 3 is a sectional view of the combination lock in accordance with the present invention; 
     FIG. 4 is a sectional view similar to FIG. 3, illustrating change in the unlocking code; 
     FIG. 5 is a sectional view illustrating engagement between a number wheel and an associated resilient sleeve; 
     FIG. 6 is an exploded view of a conventional combination lock; 
     FIG. 7 is a sectional view of the combination lock in FIG. 6; 
     FIG. 8 is an exploded perspective view of a number wheel and an associated positioning sleeve of another combination lock; and 
     FIG. 9 is a sectional view illustrating engagement between the number wheel and the positioning sleeve in FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 through 5 and initially to FIGS. 1 through 3, a combination lock in accordance with the present invention generally includes a male lock body  1  and a female lock body  2 . The male lock body  1  includes a rod  11  with a number of longitudinally spaced teeth  12  formed thereon. The female lock body  2  includes a column  21  with a longitudinal slit  212  having an opening  211  in an end face of the column  21  through which the rod  11  is inserted into the longitudinal slit  212 . A number of pairs of protrusion  215  are formed on lateral sides of the column  21 . A flat engaging section  213  is formed on the other end of the column  21  opposite to the opening  211 . The female lock body  2  further includes an elastic element  22 , a number of resilient sleeves  23 , a number of retainer plates  24 , a number of number wheels  25 , an actuating ring  26 , and a turn cap  27 . 
     The elastic element  22  is mounted around the other end of the column  21  and includes an end attached to a respective adjacent resilient sleeve  23 . Each resilient sleeve  23  is made of flexible material and includes a central hole  231  with a notched section  2311  through which the rod  11  extends. A periphery defining the central hole  231  includes a recessed section  232  for engaging with the flat engaging section  213  of the column  21 . The periphery defining the central hole  231  further includes a pair of grooves  235  for engaging with one pair of the protrusions  215  of the column  21 , thereby preventing rotation of the resilient sleeve  23 . Each resilient sleeve  23  further includes two diametrically disposed bulges  233  on an outer periphery thereof, each bulge  233  having an opening  234  therein. The openings  234  increase flexibility of the bulges  233 . 
     Each retainer plate  24  is substantially circular and includes a central hole  241  with a notched section  2411  through which the rod  11  extends. A periphery defining the central hole  241  includes an engaging section  242  which will be described later. The periphery defining the central hole  241  further includes a pair of grooves  243  for engaging with one pair of the protrusions  215  of the column  21 . More specifically, the protrusions  215  assure alignment of the notched sections  2411  of the retainer plates  24  for allowing longitudinal movement of the retainer plate only when the number wheels  25  are in their unlocking position. The protrusion  215  also prevents rotation of the resilient sleeves  23  and the actuating ring  26 . 
     An outer periphery of each number wheel  25  includes a plurality of annularly arranged numbers (generally 0-9) that are spaced by a notch or groove  251 . Each number wheel  25  includes a central hole (not labeled). A periphery defining the central hole includes an engaging section  252  with a plurality of teeth  253  (spaced by grooves  254 ) that are arranged corresponding to positions of the grooves  251 , wherein a groove  254  engages with the recessed section  242  of an associated retainer plate  24  to allow the retainer plate  24  to rotate together with the number wheel  25 . Each number wheel  25  further includes a compartment communicated with the central hole thereof, the compartment being defined by an inner periphery consisting of alternatively disposed convex portions  255  and retaining grooves  256 . Two diametrically disposed retaining grooves  256  receive the end portions of the bulges  233  of an associated resilient sleeve  23 . Thus, when the number wheel  25  is rotated from a number (e.g., 3) to another (e.g., 4), the bulges  233  generate a sound as a result of impact of the bulge  233  by the convex portions  255 . 
     The actuating ring  26  includes a central hole  261  with a notched section  2611  through which the rod  11  extends. A periphery defining the central hole  261  includes a recessed section  262  for engaging with the flat engaging section  213  of the column  21 . The periphery defining the central hole  261  further includes a pair of grooves  265  for engaging with one pair of the protrusions  215  of the column  21 . Formed on a side of the actuating ring  26  is includes a push section  263  that bears against an outermost retainer sleeve  24 . The other side of the actuating ring  26  includes a projection  264  that will be described later. 
     The turn cap  27  includes central hole  271  with a notched section  2711  through which the rod  11  extends. A periphery defining the central hole  271  includes a recessed section  276  for engaging with the flat engaging section  213  of the column  21 . The periphery defining the central hole  271  further includes an inclined slide groove  272  having two recessed ends  273  and  274  and a stopping portion  275 . The inclined slide groove  272  may engage with the projection  264  of the actuating ring  26  such that rotation of the turn cap  27  causes movement of the projection  264  along the inclined slide groove  272  to the stopping portion  275  and thus positioned by the recessed end  274 . In addition, the actuating ring  26  is moved longitudinally to disengage each retainer plate  24  from the engaging section  254  of the associated number wheel  25 , thereby allowing change in the unlocking code. 
     As illustrated in FIGS. 2 and 3, each resilient sleeve  23  and associated retainer plate  24  and number wheel  25  are mounted around the column  21  to form a unit, wherein the engaging section  242  of the retainer plate  24  engages with one of the groove  254  of the number wheel  25  so as to rotate together. The actuating ring  26  and the turn cap  27  are mounted to an end of the column  21 , wherein the inclined slide groove  272  receives the projection  264  of the actuating ring  26 . As illustrated in FIG. 2, when the grooves  243  of each retainer plate  24  align with the projections  215  of the column  21 , the notched section  2411  of each retainer plate  24  is aligned with the longitudinal slit  212  of the column  21 . Namely, the combination lock is in an unlocked position. When the grooves  243  of one of the retainer plates  24  do not align with the projections  215  of the column, the notched section  2411  of the retainer plate  24  is not aligned with the longitudinal slit  212  of the column  21 . Namely, the combination lock is in a locked position and the retainer plate  24  is not movable longitudinally. In addition, the protrusions  215  on two sides of the column  21  have different sizes such that the notched section  2411  is in the unlocking position only when the correspondingly sized grooves  243  of each retainer plate  24  are aligned with the protrusions  215 . 
     Referring to FIG. 4, when the user intends to change the unlocking code, the number wheels  25  are rotated to the unlocking code in which the recessed sections  243  of each retainer plate  24  align with the protrusions  215  of the column  21 . The turn cap  27  is then turned to cause the projection  264  of the actuating ring  26  to slide along the inclined slide groove  272  until it is stopped by and retained in the recessed end  273 . The push section  263  of the actuating ring  26  urges the retainer plates  24  to move longitudinally such that the engaging section  242  of each retainer plate  24  disengages from the engaging section  252  of the associated number wheel  25 , thereby allowing change in the unlocking code. After such change, the turn cap  27  is turned in the reverse direction such that the projection  264  of the actuating ring  26  slides along the inclined slide groove  272  until it is stopped by the stopping section  275  and retained in the recessed end  274 . The retainer plates  24  are moved longitudinally under the action of the elastic element  22  such that the engaging section  242  of each retainer plate  24  re-engages with the engaging section  252  of the associated number wheel  25 . 
     It is noted that the turn cap  27  is not rotatable when the recessed sections  243  of one of the retainer plates  24  are not aligned with the protrusions  215 , since the retainer plate  24  is stopped by the protrusions  215  of the column  21  and thus not rotatable. Thus, change in the unlocking code can be proceeded only when the combination lock is in its unlocking position. 
     Referring to FIG. 5, because each resilient sleeve  23  includes a recessed section  232  for engaging with the flat engaging section  213  of the column  21  and because the grooves  235  of each resilient sleeve  23  engage with an associated pair of protrusions  215  on the column  21 , the resilient sleeve  23  is not rotatable relative to the column  21 . The bulges  233  on each resilient sleeve  23  are impinged by the associated number wheel  25  and thus generate a sound to provide indication of position of the number wheel  25 . In addition, the bulge  233  may be retained in the retaining grooves  256 . The openings  234  increase resiliency of the bulges  233 . 
     According to the above description, it is appreciated that the combination lock of the present invention has the following advantages: 
     (1) Change in the unlocking code can be proceeded only when the combination lock is in its unlocked status. The correct unlocking code can be recognized. 
     (2) Change in the unlocking code can be proceeded without continuously holding the turn cap, as the actuating ring  26  is provided with a projection  264  for engaging with recessed end  273  of the turn cap  27 . 
     (3) the total number of elements of the combination lock of the invention is less than that for conventional combination locks and thus is more convenient to assembly procedure and reduces the malfunction possibility. 
     (4) The resilient sleeve  23  of the invention is integrally formed and includes the advantages of positioning function, sound generation, and easy assembly. This prevents the disadvantage of easy disengagement of the elastic element in FIG.  8 . 
     Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.