Patent Publication Number: US-10786048-B2

Title: Cord lock

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a divisional of U.S. patent application Ser. No. 16/003,243, filed on Jun. 8, 2018, the disclosure of which is herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cord lock for securing a cord in a set position. In particular, the invention relates to a cord lock utilizing a cam mechanism that locks the cord in position by rotation of the cam. 
     2. The Prior Art 
     Cord locks are commonly used to secure a cord in a certain position, such as on draw-string bags. The standard cord locks usually use a spring mechanism that presses an element against the cord to prevent it from sliding. The cord lock has a mechanism for compressing the spring to allow the cord to slide to a desired position. While these devices work well in situations where only a low amount of force is exerted on the cord, they cannot be used to secure a cord where higher amounts of force are exerted, because the spring mechanism is not strong enough to keep the cord in place if the force exceeds a certain amount. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a cord lock that secures the cord in position even when subjected to a high amount of force. 
     This object is accomplished by a cord lock having 
     a housing having two side walls, a top surface, a bottom surface, a front, a back, an interior cavity and an opening extending between the front and the back for receiving a cord, and an actuator having a top surface, a bottom surface and two legs extending from the bottom surface, the legs being configured to slide within the interior cavity of the housing. A spring is disposed between the top surface of the housing and the bottom surface of the actuator to bias the actuator in a raised position relative to the housing. There is a cam disposed in the interior cavity of the housing. The cam has a front surface, a back surface, a top and a bottom. The bottom of the cam is rotatably connected to the housing and the top of the cam is rotatably connected to the legs of the actuator. In a resting position, the upward force of the uncompressed spring presses the top of the cam against the housing such that when a cord is extended through the opening, the cam locks the cord in place between the cam and the housing. Depressing the actuator compresses the spring and rotates the cam. This opens up enough space in the housing to allow the cord to slide freely to a new position. Releasing the actuator allows the spring to return to its uncompressed position, which forces the cam back into the locking state on the cord. 
     To increase the grip of the cam on the cord, the top of the cam is equipped with teeth that can dig into the cord in the locked position. Lateral pressure on the cord causes the teeth to grip more deeply into the cord, so pulling on the cord will not release it from the cam, particularly in a direction where the cam is then pressed more firmly against the top of the cavity in the housing. 
     In order to keep the spring in place, the top of the housing has a protrusion that extends into an interior of the spring. This prevents the spring from sliding laterally within the housing during use. 
     To connect the cam to the housing and actuator, the cam has side walls with protrusions that extend into corresponding apertures in the side walls of the housing and in the legs of the actuator. The cam is mounted so that the bottom of the cam is offset from the top of the cam, so that the cam is arranged oblique to a vertical axis of the cord lock. In particular, the bottom of the cam is arranged offset from the vertical axis along which the spring is compressed. This way, downward pressure on the actuator causes the bottom of the cam to rotate about the protrusions extending into the side walls of the housing, and causes the top of the cam to move in an arc downward into the cavity, guided by the cooperating protrusions and apertures in the legs of the actuator. The protrusions in the legs are elongated to accommodate the arc along which the top of the cam travels. This rotational motion of the cam opens up a passage in the housing to allow the cord to slide freely therethrough. Releasing the actuator moves the cam back into the starting locked position, preventing any further movement of the cord. This rotational motion of the cam also means that pulling on the cord causes the cam to rotate to an even more locked position against the top of the housing, so that the harder the cord is pulled, the more tightly it is locked in place. 
     In one embodiment, the actuator has two side walls extending from its bottom surface. The side walls are located on an outside edge of the actuator such that a slot is formed on each side of the actuator between a corresponding one of the legs and each of the side walls. The side walls of the housing fit within these slots when the actuator is inserted into the housing. This arrangement stabilizes the actuator and prevents any lateral movement as it slides up and down the housing. 
     In an alternative embodiment of the invention, the cord lock can be configured as a double cord lock—with two sets of each of the elements described above, to lock two cords in the housing simultaneously. In this embodiment, the housing has a second interior cavity and there is a second one of the actuators configured to slide within the second interior cavity. A second spring is mounted between the second actuator and the housing, and a second one of the cams is rotatably connected to the legs of the second actuator and to the side walls of the housing. 
     Preferably, the two actuators are mounted on opposite ends of the housing and are positioned so that the springs are compressed by pressing the actuators toward each other. This way, the two cords can be released in a single action, using only one hand. 
     In this embodiment, the cams are mounted so that the bottom of the cams are arranged adjacent one another near the center of the cord lock and offset from a longitudinal center on the same side, and the tops of the cams are located remote from one another, such that the cams grip the cords tighter when the cords are pulled in the same direction. 
     In another embodiment of the invention, a different actuating and spring mechanism is used to actuate the cam. In this embodiment, the cord lock has a housing having two side walls, a top surface, a bottom surface, a front, a back, an interior cavity and an opening extending between the front and the back for receiving a cord, and a cam disposed in the interior cavity. The cam has a channel therethrough, an actuating hook and a gripping portion. A post extends through the channel in the cam and is rotatably connected to the side walls of the housing by extending through apertures in the housing. A spring is connected to the post for biasing the cam in a locked position, such that a cord extending through the opening is pressed against the housing by the gripping portion of the cam. An actuator is provided for actuating the cam. The actuator has a cross-bar configured for arrangement in the actuating hook, and a handle arranged opposite the cross-bar, such that pressing the lever moves the cam out of the locked position to release the cord from the housing. 
     To support the actuator on the housing, the housing has protrusions extending from the side walls, and the side walls of the actuator rest on the protrusions when the cross bar is arranged in the actuating hook. These protrusions form a pivot point for the handle when it is pressed to release the cam. 
     Preferably, the spring is a torsion spring extends around the post. In this embodiment, the channel has a slot that is configured for accommodating an end of the torsion spring. The other end of the torsion spring is biased against the housing, so that the tension between the two ends of the spring keeps the cam in the locked position unless the lever is moved, which then overcomes the spring force of the spring to release the cam. 
     In order to increase the locking of the cord, the gripping portion of the cam contains a plurality of teeth, which dig into the cord when the cam is in the locked position. 
     The present invention provides a novel way of locking the cord, by using a cam element that can withstand greater lateral forces because lateral forces only cause the cam to rotate and lock the cord in even tighter to the cord lock. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
       In the drawings, wherein similar reference characters denote similar elements throughout the several views: 
         FIG. 1  shows a cross sectional view of a traditional cord locking device according to the prior art; 
         FIG. 2  shows one embodiment of the cord lock according to the invention with the cam removed; 
         FIG. 3  shows a side view of the cord lock; 
         FIG. 4  shows a front view of the cord lock; 
         FIG. 5  shows an exploded view of the cord lock; 
         FIG. 6  shows a cross-sectional view along lines A-A of  FIG. 4 ; 
         FIG. 7  shows the cross-sectional view of  FIG. 6  with a cord inserted therein; 
         FIG. 8  shows a perspective view of a second embodiment of the cord lock according to the invention; 
         FIG. 9  shows a front view of the cord lock of  FIG. 8 ; 
         FIG. 10  shows a rear view of the cord lock of  FIG. 8 ; 
         FIG. 11  shows a cross-sectional view along lines B-B of  FIG. 10 ; 
         FIG. 12  shows a third embodiment of the cord lock according to the invention; 
         FIG. 13  shows an exploded view of the components of the cord lock of  FIG. 12 ; 
         FIG. 14  shows a front view of the cord lock of  FIG. 12 ; a 
         FIG. 15  shows a cross-sectional view along lines C-C of  FIG. 14 ; and 
         FIG. 16  shows the view of  FIG. 15  in a released position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now in detail to the drawings and, in particular,  FIG. 1  shows a prior art cord lock  1 , which has a housing  2  and an actuator  3  that is held in a biased position by a spring  4 . A cord  100  extends through a hole in the housing, and the biased force of actuator  3  keeps cord  100  in position. The problem with this arrangement is that it is relatively easy to overcome the force of the spring, as lateral force on the cord runs perpendicular to the spring force. 
     One embodiment of the cord lock according to the invention is shown in  FIGS. 2-7 . Here, cord lock  10  comprises a housing  11  having an interior cavity  12 , side walls  13  and a front  14  with an opening  15 . An actuator  20  is positioned on the top of housing  11 , and has legs  21  that slide within side walls  13  of housing  11 . Side walls  22  of actuator  20  slide up and down in an indentation  18  in the outside of side walls  13 , so that side walls  13  of housing  11  fit within a groove  23  of actuator  20 , to keep actuator  20  in position on housing  11 . A spring  30  is mounted on a post  16  of housing  11 , and rests against the underside of actuator  20 . In a resting position, spring  30  biases actuator  20  in a raised position. Spring  30  is a compression spring that can be compressed by pressing downward on actuator  20 . 
     A cam  40  is connected to both the housing  11  and actuator  20 . As shown in  FIG. 5 , cam  40  has protrusions  41 ,  42  on each of its side walls  43 . Protrusions  42  extend through apertures  17  in housing  11 , and protrusions  41  extend through apertures  26  in actuator  20 , to rotatably connect cam  40  to housing  11  and actuator  20 . When the cord lock  10  is fully assembled, cam  40  is arranged so that the bottom is offset from the top, leading to an oblique arrangement of cam  40  in housing  11 , as can be seen in  FIGS. 6 and 7 . In a resting position as shown in  FIG. 6 , the pressure of spring  30  keeps actuator  20 , and consequently cam  40 , in a fully raised position, where cam  40  is essentially completely blocking opening  15 . The offset orientation of cam  40  means that the lateral motion of actuator  20  up and down causes cam  40  to rotate about the pivot points created by projections  41  and  42 . This arrangement, as shown in  FIG. 7 , allows a cord  100  to be locked in place in cord lock  10 . The upward pressure on cam  40  keeps cord  100  firmly in place. Teeth  44  dig into cord  100  and keep it from slipping. Any lateral force to the right as shown by the arrow only causes cam  40  to rotate toward a more vertical position and secure cord  100  even more firmly in place. To release cord  100 , the user must press down on actuator  20 , which then causes cam  40  to rotate counter-clockwise to achieve a more horizontal position, and open up space in opening  15  for cord  100  to slide free. 
     An alternative embodiment of the cord lock is shown in  FIGS. 8-11 . Here, cord lock  80  is essentially two of cord locks  10  from  FIGS. 2-7  that are put together into a single unit. As shown in  FIG. 8 , cord lock  80  comprises a housing  81  with two interior cavities  82  that house cams  90 , which are rotatably connected to housing  81  and actuators  110  in the same manner as described with respect to  FIGS. 2-7 . Apertures  84 ,  85  in housing  81  accommodate corresponding protrusions in cam  90  to rotatably hold cam  90  in place. Actuators  110  each have legs  111  that extend into housing  81  to connect with the top portion of cams  90 . Compression springs  95  keep cams  90  in a biased position, to hold two cords simultaneously in position in cord lock  80 . Cams  90  are positioned so that the tops of cams  90  face away from each other, and they rotate in opposite directions upon pressing of actuators  110 , as shown in  FIG. 11 . This allows actuators  110  to be pressed simultaneously by squeezing them together, which can be done by a single hand. As with the first embodiment, cams  90  can be equipped with teeth  96  for better gripping of the cords. 
     Another embodiment of the invention is shown in  FIGS. 12-16 . Here, cord lock  200  is formed from a housing  210  having an interior cavity  220  in which a cam  230  is rotatably mounted on a post  240 . Post  240  extends through channel  231  in cam  230 , and through apertures  222 ,  223  in housing  210  to mount cam  230  to housing  210 . Channel  231  has a cutout  234  for accommodating the end  251  of torsion spring  250 , which extends around post  240  and keeps cam  230  in a biased position in cavity  220  of housing  210 . This biased position is shown in  FIG. 15 , where teeth  233  of cam  230  are shown abutting the top of housing  210 . A cord (not shown) can be extended between teeth  233  and the top of housing  210  maintained there under pressure by spring  230 . Attempts to pull a cord to the right only cause cam  230  to rotate into an even further locked position and prevent all movement of a cord. 
     To enable adjustment of the cord, an actuator  260  is connected to cam  230 , by placing bar  262  of actuator  260  underneath hook  232  of cam  230 . Then, edges  264  of actuator  260  rest on protrusions  225  of housing  210 . Protrusions  225  act as pivot points for actuator  260 , so that pressing down on handle  261  of actuator  260 , causes actuator  260  to rotate around protrusions  225 , raising bar  262 , and thereby causing cam  230  to rotate to an open position, as shown in  FIG. 16 . This allows a cord to be adjusted or removed, before releasing actuator  260  and cam  230  back into the resting biased position shown in  FIG. 15 . 
     Accordingly, while only a few embodiments of the present invention have been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.