Abstract:
An adjustable key-locked clamp for securing car stereo equipment against a mounting surface. A single rotary lock fixes the adjustable clamping member and secures the clamp to its base. A key is required to release the clamping member and remove the device from its base. Thus, without the key, it is very difficult to remove the car stereo equipment.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of car stereo equipment. More specifically, the invention comprises an adjustable key-locked clamp for securing car stereo equipment against a mounting surface. A single rotary lock fixes the adjustable clamping member and secures the clamp to its base. 
     2. Background 
     Modern car stereos often employ large power amplifiers. The bulk of these devices—along with their heat dissipation requirements—require that they be mounted in the vehicle&#39;s trunk. They are typically screwed to the trunk floor or wall. FIG. 1 shows a typical installation of amplifier  12 . It is shown mounted to the bottom wall of an automotive trunk  10 . Amplifier  12  is typically mounted using screws or adhesive strips. 
     Unfortunately, as high-quality amplifiers are expensive, theft has become a problem. It is therefore desirable to create a securing device which will deter the theft of these components. It is also desirable to make such a device adjustable, since power amplifiers come in many different shapes and sizes. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Accordingly, several objects and advantages of the present invention are: 
     1. To provide a device for securing a power amplifier to an automobile, so that only a user with a key can remove it; 
     2. To provide an adjustable locking device which can be used to secure many different sizes and shapes of power amplifiers; and 
     3. To use a single mechanism to both fix the adjustable component in place and lock the clamp to the power amplifier. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is an isometric view, showing a power amplifier mounted in the trunk of a car. 
     FIG. 2 is an isometric view with a cutaway, showing the base and foot components. 
     FIG. 3 is an isometric view with a cutaway, showing the housing attached to the foot. 
     FIG. 4 is an isometric view with a cutaway, showing housing with the adjustable sliding member in position. 
     FIG. 5 is an isometric view with a cutaway, showing additional internal components. 
     FIG. 6 is an isometric view, showing the pressure plate in greater detail. 
     FIG. 7 is an isometric view with a cutaway, showing the complete assembly in the unlatched position. 
     FIG. 8 is an isometric view with cutaways, showing the complete assembly in the latched position. 
     FIG. 9 is an isometric view, showing the invention clamping an amplifier in place. 
     REFERENCE NUMERALS IN DRAWINGS 
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     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows amplifier  12  positioned within automobile trunk  10  (automobile trunk  10  is obviously a simplified representation). Amplifier  12  is typically secured by screws, hook-and-pile fastener strips, or bonding tape. In the event of a robbery, any of these securing methods may be easily defeated. The present invention seeks to remedy this problem. Base  14  is bolted in place immediately adjacent amplifier  12 . As shown, it is typically bolted to the floor panel of trunk  10 . 
     FIG. 2A shows base  14  in greater detail. It is secured by placing bolts through mounting holes  16 . These bolts may be installed and removed using conventional tools. However, as will be made clear in the following, the invention does not allow an unauthorized user to access the securing bolts. 
     Base  14  has four undercut slots  18 . The reader will observe that these are in the shape of the letter “L.” They carry through the body of base  14  and out the front wall. They do not carry out the rear wall. Foot  22  is designed to lock into base  14 . Foot  22  has four cleats  26  descending from its lower surface. The reader will observe that these cleats  26  are sized and positioned to snugly engage the undercut slots  18  in base  14 , when foot  22  is pushed onto base  14  in the direction indicated by the arrow. Because undercut slots  18  do not go all the way through to the rear wall of base  14 , foot  22  will come to a hard stop when the user slides it onto base  14 . It is important to realize that the only way to disengage foot  22  from base  14  is by sliding foot  22  in the reverse of the direction indicated by the arrow. 
     FIG. 2B shows foot  22  with a portion cut away in order to reveal some of its internal details. Foot  22  has two latch cavities  28 . These line up with two latch receptacles  20  in base  14  (when foot  22  is locked into base  14 ). Two latches  24  are positioned within latch cavities  28 . Although these fit snugly within latch cavities  28 , they are free to move up and down. Each latch  24  is configured so that when it is pressed down as indicated, the lower portion protrudes beyond the bottom surface of foot  22  and down into latch receptacle  20  on base  14 . Thus, when the two latches  24  are extended downward, foot  22  is prevented from sliding relative to base  14 . In this situation, foot  22  is locked to base  14 . 
     Springs are placed under each latch  24  within each latch cavity  28 . These springs bias each latch  24  upward, so that foot  22  is not normally locked to base  14 . Only when latches  24  are pressed downward are the two components locked together. As such springs are well known to those skilled in the art, they have not been illustrated. 
     A camming fin  30  is located on the top of each latch  24 . Camming fins  30  are acted upon by other components to force latches  24  downward—as will be explained subsequently. 
     FIG. 3 shows foot  22  with housing  32  attached and extending upward. Housing  32  is shown as a cutaway in order to illustrate its thin-walled nature. In actuality, housing  32  covers all of foot  22 . The rear portion of housing  32  is open. This open area is bordered on each side by a retaining flange  58  (because of the cutaway view, only one side is illustrated). 
     FIG. 4 shows foot  22 , with housing  32  attached, placed on base  14 . Clamp  34  is positioned to slide up and down along the rear portion of housing  32 . The forward portion of clamp  34  has four pin bosses  36 . These pin bosses mount two freely rotating pins  38 . A wheel  40  is formed on both ends of each pin  38 . As clamp  34  is moved up and down, wheels  40  roll along retaining flange  58 . 
     Clamp  34  is freely adjustable. However, in order for the invention to function properly, it must be possible to lock clamp  34  in a desired position. A locking member is needed. Each side wall of housing  32  also has a retaining rib  56 , positioned to hold this locking member in place within housing  32 . 
     FIG. 5 illustrates the locking member itself—pressure plate  42 . The forward surface of pressure plate  42  has cam boss  44 . Cam groove  60  is cut across cam boss  44 . FIG. 6 illustrates pressure plate  42  in greater detail. The rear face of pressure plate  42  has a plurality of pin grooves  64 . Pin grooves  64  are sized to fit snugly over pins  38 . Returning to FIG. 5, the reader will observe that if pressure plate  42  is forced rearward (indicated by the arrow), pin grooves  64  will engage pins  38 , and wheels  40  will be pressed against the two retaining flanges  58 . If pressure plate  42  is restricted from moving up and down, clamp  34  will be locked in vertical position by the action of pressure plate  42 . 
     FIG. 7 illustrates the mechanisms for forcing pressure plate  42  rearward, and for forcing latches  24  downward. Lock  48  is secured within lock mount  46 . Lock  48  is of the typical drum variety. When a key is inserted in the slot shown, it is possible to rotate lock  48  through a 45 degree arc. The shaft of lock  48  has two significant features rigidly attached thereto. Rotary cam  50  is positioned immediately below the cylinder. Latch plate  54  is at the lower end of the lock shaft. The reader will observe that bearing  52  is provided to stabilize the lock shaft (Bear in mind that housing  32  is still shown as a ½ cutaway). 
     As lock  48  is rotated in the direction indicated, rotary cam  50  engages cam groove  60  and forces pressure plate  42  against pins  38 . Simultaneously, latch plate  54  is rotated and bears against the camming fin  30  on the top of each latch  28 . The two latches  28  are oriented oppositely so that the rotary motion of latch plate  54  forces both latches downward. 
     It is important to realize that rotary cam  50  never completely disengages from cam groove  60 , even in the fully unlocked position. This is significant, because this feature is what prevents pressure plate  42  from moving vertically when the mechanism is in the unlocked position. 
     FIG. 8 illustrates lock  48  rotated to the fully locked position. The reader will observe that the interaction of rotary cam  50  and camming slot  60  has forced pressure plate  42  against pins  38 . The reader will also observe that the rotation of latch plate  54  has forced the two latches  24  fully downward. Thus, clamp  34  is locked in position and foot  22  is locked to base  14 . A single turn of lock  48  has fixed the position of the adjustable clamp  34  and locked the unit in place on base  14 . It cannot be removed without the key. 
     FIG. 9 shows the invention in use. In this view, housing  32  is shown with no cutaway. With the key in the unlocked position, the user slides foot  22  onto base  14 . Net, the user lowers clamp  34  until it rests against amplifier  12 . Then the user turns lock  48  to the locked position—as shown. Clamp  34  is thereby locked in place. In addition, foot  22  is locked onto base  14 . The result is that amplifier  12  may not be removed without the key to lock  48 . 
     SUMMARY, RAMIFICATIONS, AND SCOPE 
     Accordingly, the reader will appreciate that the proposed invention allows a user to secure a variety of amplifiers against theft. The invention has further advantages in that it uses a single mechanism to both fix the adjustable component in place and lock the clamp to the power amplifier. 
     Although the preceding description contains significant detail, it should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiment of the invention. As an example—even though the invention has been illustrated as mounting to a horizontal surface, it could easily be mounted to a vertical surface so as to lock an amplifier or other component in a different orientation. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given.