Abstract:
A latching mechanism includes an aperture surface through which a threaded rod may pass. Half of the surface of the aperture is smooth and fixed in place relative to a housing. The other half is threaded and formed from an internal module that is slidable within the housing. The internal module is biased by a spring towards the fixed portion of the aperture surface. Flaring tabs on either side of the internal module support the internal module within the housing to ensure that a minimum of contact is established between the housing and the internal module so as to present a smooth latching/unlatching action.

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to a height-adjusting system. In particular, the present invention discloses a height-adjusting system that permits rapid rough adjustments of the extension of a supporting leg, and which further permits fine adjustments to the extensional length of the supporting leg. 
     2. Description of the Prior Art 
     Please refer to FIG.  1 . FIG. 1 illustrates a typical setup for a projector  10 . The projector  10  rests on a flat surface  12 , such as a table, and projects an image onto a screen  14 . As the height of the screen  14  may vary with respect to the projector  10 , a tilt adjust system  18  is provided on the projector  10  to adjust a projection angle θ of the projector  10 , and hence the position of the image on the screen  14 . 
     Please refer to FIG. 2 with respect to FIG.  1 . FIG. 2 is a front view of the tilt adjust system  18  for the projector  10 . The prior art tilt adjust system  18  typically consists of two legs  18 L. Each leg  18 L has a threaded support rod  18 R, a foot  18 F, and a correspondingly threaded bolt  18 B. The support rod  18 R screws into the bolt  18 B. By turning the support rod  18 R (for example, by way of the foot  18 F), a relative distance d between the foot  18 F and the bolt  18 B may be changed, thereby changing the height of the front end of the projector  10  and hence the projection angle θ. 
     The prior art tilt adjust system  18  provides a simple and secure footing for the projector  10 . However, actually changing the projection angle θ can be a somewhat tedious process for the user, as it can involve turning each of the support rods  18 R a great number of times. To facilitate this task, the user may place the projector  10  onto its side, so that the feet  18 F are not in contact with the surface  12 , and hence easier to turn. All of this is inconvenient 
     SUMMARY OF THE INVENTION 
     It is therefore a primary objective of this invention to provide a height-adjusting system for a device, such as a projector, that is easy to use and to adjust, and which provides secure footing for the device. 
     Briefly, the preferred embodiment of the present invention discloses a latching mechanism for a height-adjusting system. The latching mechanism includes a first housing, an internal module slidably disposed within the first housing, and a second housing that locks onto the first housing. The first housing has a bottom surface with a central opening for accepting a height-adjusting rod, a brace mounted on the bottom surface adjacent to the central opening, first and second surfaces respectively disposed on first and second sides of the first housing, and a third surface disposed on a third side of the first housing. The brace has a bracing surface that is substantially aligned with an edge of the central opening, and the bracing surface is adapted to brace the height-adjusting rod. The internal module includes a central portion having a first opening with a contact surface, first and second tabs extending respectively from first and second sides of the central portion, and a third tab extending from a third side of the central portion. The first, second and third tabs are respectively disposed over the first, second and third surfaces. The brace is disposed within the first opening. The bracing surface of the brace faces towards the contact surface on the first opening. Mechanical interaction between the first and second tabs and the first and second surfaces prevents the central portion from contacting the bottom surface so as to provide a smoother latching/unlatching action. When the central portion is in a first position, the contact surface of the first opening presses the height-adjusting rod against the bracing surface to latch the height-adjusting rod into position. When the central portion is in a second position, the contact surface of the first opening is sufficiently spaced from the bracing surface to enable the height-adjusting rod to slide between the bracing surface and the contact surface. The third tab acts as a button that a user may press to move the internal module to the second position so as to unlatch the height-adjusting rod and so quickly change the tilt angle of the projector. Both the contact surface and the height-adjusting rod are threaded, which enables the contact surface to mechanically engage with, and hence latch onto, the height-adjusting rod. When latched into position, the height-adjusting rod may be turned to permit fine adjustments to height. 
     It is an advantage of the present invention that by pressing the third tab as a button, the user may quickly latch and unlatch the height-adjusting rod, and so quickly change the extensional height of the height-adjusting rod. This would correspond to quick, rough adjustments to the height of the device, such as the tilt of a projector. Changing the projection angle is thus made both easier and quicker. Additionally, the action of the latching device is made smooth by the first and second tabs, as the internal module contacts the housing primarily only at the first and second tabs. Finally, as noted above, fine adjustments to the height of the device are possible by turning the height-adjusting rod. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective view of a typical set-up for a projector. 
     FIG. 2 is a front view of a projector shown in FIG.  1 . 
     FIG. 3 is a front view of a projector utilizing a height-adjusting system according to the present invention. 
     FIG. 4 is a perspective view of a present invention height-adjusting system. 
     FIG. 5 is a perspective view showing internal structure of a height-adjusting system according to the present invention. 
     FIG. 6 is a top perspective view of a first housing of the present invention. 
     FIG. 7 is a top perspective view of the internal structure of a latching mechanism according to the present invention. 
     FIG. 8 is a perspective view of a projector utilizing latching mechanisms according to the present invention. 
    
    
     DETAILED DESCRIPTION 
     Please refer to FIG.  3 . FIG. 3 is a front view of a projector  20  utilizing height-adjusting systems  30  according to the present invention. Each height-adjusting system  30  includes a height-adjusting rod  40  and a latching mechanism  50 . The height-adjusting rod  40  passes through the latching mechanism  50 , and mechanical interaction between the height-adjusting rod  40  and the latching mechanism  50  keeps the height-adjusting rod  40  firmly secured into position with respect to the latching mechanism  50 . However, when a button  50 B on the latching mechanism  50  is depressed, the height-adjusting rod  40  mechanically disengages from the latching mechanism  50  and may slide freely through the latching mechanism  50 . In this manner, a distance D between a foot  42  of the height-adjusting rod  40  and a bottom surface  22  of the projector  20  may be changed. The projection angle of the projector  20  is thereby adjusted. The foot  42  may have a relatively soft, gripping bottom surface (such as soft rubber) so as to prevent scratching to any surface upon which the foot  42  rests, as well as to prevent sliding of the projector  20 . 
     Please refer to FIG.  4 . FIG. 4 is a perspective view of the height-adjusting system  30 . The latching mechanism  50  includes a second housing  57  locked onto a corresponding first housing  58  by way of a snap mechanism  59 . Together, the corresponding shapes of the second housing  57  and the first housing  58  present a first opening  51  (not visible in FIG.  4 ), a second opening  52 , and a third opening  53 . The button  50 B protrudes through the third opening  53 . 
     Please refer to FIG. 5 with respect to FIG.  4  and FIG.  3 . FIG. 5 is a perspective view of the height-adjusting system  30  with the second housing  57  removed so as to enable viewing of the internal structure of the latching mechanism  50 . The first housing  58  has a first side  58 F, a second side  58 S, a third side  58 T and a fourth side  58 R. An internal module  60  lies slidably disposed within the first housing  58 . A central portion  62  of the internal module  60  has a first opening  64 . The height-adjusting rod  40  passes through the first opening  64 . The internal module  60  can slide in a forward and backward direction, as indicated by arrow FB, within the first housing  58 . A spring  90 , disposed between the fourth side  58 R and the central portion  62  of the internal module  60 , tends to push the internal module  60  towards the third side  58 T. When pushed towards the third side  58 T, mechanical interaction between the internal module  60  and the height-adjusting rod  40  secures the height-adjusting rod  40  into position. Pressing on the button  50 B overcomes the mechanical biasing of the spring  90 , and pushes the internal module  60  towards the fourth side  58 R; doing so disengages the height-adjusting rod  40  from the internal module  60  so that the height-adjusting rod  40  may freely slide through the first opening  64 . The first housing  58  has a notch  58 N that engages with a corresponding hook  57 H on the second housing  57  to enable the second housing  57  to lock onto the first housing  58 . The first housing  58  also has a mounting fixture  58 M that enables the latching mechanism  50  to be mounted onto a device, such as the projector  20 . 
     Please refer to FIG. 6 with reference to FIG.  4 . FIG. 6 is a top perspective view of the first housing  58 . The first housing  58  has a bottom surface  58 B. The bottom surface  58 B has a central opening  58 C, through which the height-adjusting rod  40  passes. The central opening  58 C should be just large enough to permit the height-adjusting rod  40  to pass freely through the central opening  58 C. A brace  59  is mounted onto the bottom surface  58 B adjacent to the central opening  58 C. The brace  59  has a bracing surface  59 B. The bracing surface  59 B has a concave shape that substantially conforms to the surface shape of the height-adjusting rod  40 , and which is aligned with the perimeter of the central opening  58 C. When disposed through the central opening  58 C, the height-adjusting rod  40  runs along the bracing surface  59 B, contacting the bracing surface  59 B. The bracing surface  59 B presents a smooth surface for the height-adjusting rod  40 , so that the height-adjusting rod  40  may slide easily against the bracing surface  59 B. To present such a surface, the bracing surface  59 B is ideally made from a hard, smooth plastic, such as the industrial-standard plastic nylon66. The first housing  58  has a first surface  59 F on the first side  58 F, and a similar second surface  59 S on the second side  585 . The first and second surfaces  59 F and  59 S, together with conformal surfaces on the second housing  57 , form the first and second openings  51  and  52 . Similarly, a third surface  59 T on the third side  58 T combines with a conformal surface on the second housing  57  to form the third opening  53 . 
     Please refer to FIG. 7 with respect to FIG.  6  through FIG.  3 . FIG. 7 is a top perspective view of the internal structure of the latching mechanism  50 . As noted earlier, the internal module  60  is slidably disposed within the first housing  58 . The internal module  60  is disposed within the first housing  58  with the brace  59  disposed within the first opening  64  of the central portion  62  of the internal module  60 . The first opening  64  has a shape that is conformal to the shapes of the brace  59  and the height-adjusting rod  40 . The brace  59  helps to prevent excessive wobbling of the internal module  60  within the latching mechanism  50 , and can act as a limiting means to prevent the internal module  60  from moving to far towards the fourth side  58 R. Of particular importance as regards the design of the internal module  60  is a contact surface  60 B presented by the internal surface of the first opening  64 . The contact surface  60 B is conformal with the surface shape of the height-adjusting rod  40 , and together with the bracing surface  59 B of the brace  59 , is capable of pinching the height-adjusting rod  40 . With the spring  90  biasing the internal module  60  forward towards the third surface  58 T, the contact surface  60 B is brought closer towards the bracing surface  59 B. The height-adjusting rod  40  is thus pinched, or clamped, between the two surfaces  59 B and  60 B. In particular, the height-adjusting rod  40  is threaded. The contact surface  60 B is similarly threaded. When pinched between the bracing surface  59 B and the contact surface  60 B, the threaded surface of the height-adjusting rod  40  mechanically engages with the threaded surface of the contact surface  60 B to securely latch the height-adjusting rod  40  into position. While so latched, rotating the height-adjusting rod  40  clockwise or counter-clockwise permits fine adjustments to the distance D between the projector  20  and the feet  42 . Alternatively, pressing on the button  56 B against the bias of the spring  90  causes the internal module  60  to slide back towards the fourth side  58 R. The contacts surface  60 B is then spaced farther apart from the bracing surface  59 B, and the height-adjusting rod  40  is no longer pinched between the two surfaces  59 B and  60 B. This permits the threaded surface of the height-adjusting rod  40  to mechanically disengage from the correspondingly threaded surface of the contact surface  60 B, and so slide freely through the openings  58 C and  64 . Of course, the second housing  57  also has a central opening  57 C through which the height-adjusting rod  40  passes. Note that only the contact surface  60 B is threaded, whereas the bracing surface  59 B is smooth. This is important, enabling the height-adjusting rod  40  to easily slide up and down when disengaged from the contact surface  60 B (i.e., when the button  50 B is pressed). Only one of the surfaces  59 B,  60 B should be threaded; the other should be smooth. It is thus certainly possible to make the contact surface  60 B smooth and the bracing surface  59 B threaded. The central portion  62  of the internal module  60  may be thought of as having two distinct positions (as measured relative to a forward point): a first position SOL in which the internal module  60  is pushed as far forward as possible towards the third side  58 T so as to secure the height-adjusting rod  40  into place, and a second position  50 U in which the internal module  60  is pushed towards the fourth side  58 R so as to unlatch the height-adjusting rod  40  from the contact surface  60 B. 
     The central portion  62  of the internal module  60  further comprises a first tab  66 F and a second tab  66 S. The first tab  66 F, extending from a first side  60 F of the central portion  62 , is disposed within the concave cavity formed by the first surface  59 F. Similarly, the second tab  66 S, extending from a second side  60 S of the central portion  62 , is disposed within the concave cavity of the second surface  59 S. The first tab  66 F and the second tab  66 S are of particular importance for the smooth operation of the latching mechanism  50 . The first and second tabs  66 F and  66 S contact their respective surfaces  59 F and  59 S to prevent the central portion  62  from contacting the bottom surface  58 B of the first housing  58 . That is, the first tab  66 F and the second tab  66 S keep the internal module  60  raised off from the bottom surface  58 B. Consequently, when the internal module  60  slides forwards or backwards, friction is induced only from the relatively smaller surface contact points between the tabs  66 F and  66 S and their respective surfaces  59 F and  59 S, and not between the central portion  62  and the bottom surface  58 B. This presents considerably less friction than if the entire central portion  62  were in contact with the bottom surface  58 B. The action of the latching mechanism  58  thus presents a smoother and easier action for a user. Of course, conformal surfaces on the second housing  57 , which coincide with the first and second surfaces  59 F and  59 S to form the openings  51  and  52 , also work with the first and second tabs  66 F and  66 S to prevent the central portion  62  of the internal module  60  from contacting the second housing  57 . A third tab  66 T extends from a third side  60 T of the central portion  62 , and is disposed within and through the concave cavity of the third surface  59 T to present the button  50 B. Ideally, the third tab  66 T should not contact the third surface  59 T, nor should the third tab  66 T contact the conformal surface on the second housing  57  that forms the third opening  53 . That is, the third surface  59 T should not contact the third opening  53 . Finally, a fourth tab  66 R extends from a fourth side  60 R of the central portion  62 , and is disposed within a concave fourth surface  59 R of the first housing  58 . The spring  90  is wound around the fourth tab  66 R, and so is capable of being compressed between the fourth side  60 R of the central portion  62  and the fourth side  58 R of the first housing  58 , and thus biases the internal module  60  forward towards the third side  58 T of the first housing  58 . 
     With reference to FIG. 8, it should be noted that it is not strictly necessary for the latching mechanism  50  to be mounted externally to a device. A projector  90  is built with the latching mechanisms  50  mounted within the housing  92  of the projector  90 . Respective buttons  50 B extend out through the housing  92  and may be depressed by a user so as to quickly adjust the extensional height H of feet  94 . Note that height-adjusting rods  40  thus pass through both top and bottom surfaces of the housing  92 . 
     In contrast to the prior art, the present invention provides a quick-release mechanism in the form of a button that a user may depress to quickly unlatch and adjust a height-adjusting rod. The latching mechanism is formed by two surfaces, one moveable and connected to the button, the other fixed to a first housing. One of the surfaces is threaded, as is the height-adjusting rod. These interacting threaded surfaces latch the height-adjusting rod into position, and enable fine adjustments of the height-adjusting rod by simply rotating the height-adjusting rod clockwise or counter-clockwise. Two support tabs ( 66 F and  66 S) are utilized to present a smooth action for the latching mechanism by keeping the central portion of the internal module from contacting the first or second housings. Quick rough adjustments to the height of a device, such as for a projection tilt angle, are possible by depressing the button to unlatch the height-adjusting rod and so allow the unlatched height-adjusting rod to move freely through the latching mechanism. Fine adjustments are possible by rotating the latched height-adjusting rod in the manner of a screw-like device. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.