Abstract:
A rotary motion mechanism including a rotatable element geometrically lockable at two points (e.g., limits) of travel, and a linear motion element linked to the rotatable element, the linear motion element being adapted to move in response to a linear motion imparted thereto and to cause rotation of the rotatable element.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to mechanisms for transferring linear motion to rotary motion.  
       BACKGROUND OF THE INVENTION  
       [0002]     Many devices are known for transferring linear motion to rotary motion. For example, the linkage in an internal combustion engine between the pistons and the crankshaft transfers the linear reciprocating motion of the pistons to the rotary motion of the crankshaft. Some mechanisms that transfer linear to rotary motion, such as in the example of the linkage in the engine, are dedicated to continuous motion. Other mechanisms, instead of providing continuous motion, constrain the motion between limits of travel. Some push-pull or toggle mechanisms are examples of such mechanisms. However, the known mechanisms lack the ability to geometrically lock at the limits of travel.  
       SUMMARY OF THE INVENTION  
       [0003]     The present invention seeks to provide an improved mechanism for transferring linear motion to rotary motion, wherein the rotary motion is constrained between two points of travel, and wherein there is geometrical locking at the points of travel.  
         [0004]     There is thus provided in accordance with a preferred embodiment of the present invention a rotary motion mechanism including a rotatable element geometrically lockable at two points (e.g., limits) of travel, and a linear motion element linked to the rotatable element, the linear motion element being adapted to move in response to a linear motion imparted thereto and to cause rotation of the rotatable element.  
         [0005]     In accordance with a preferred embodiment of the present invention the two points of travel are defined by structure formed in the rotatable element.  
         [0006]     Further in accordance with a preferred embodiment of the present invention the structure comprises a plurality of grooves adapted for receiving therein a portion of the linear motion element, wherein one of the grooves defines a first point of travel of the rotatable element when the portion of the linear motion element is received therein, and another of the grooves defines a second point of travel of the rotatable element when the portion of the linear motion element is received therein.  
         [0007]     Still further in accordance with a preferred embodiment of the present invention the rotatable element is rotatable about a pivot and at least two of the grooves are offset from the pivot.  
         [0008]     In accordance with a preferred embodiment of the present invention the linear motion element is adapted to cause the rotatable element to rotate when the portion of the linear motion element is not positioned in the grooves that define the points of travel.  
         [0009]     Further in accordance with a preferred embodiment of the present invention the plurality of grooves comprises a groove that is not one of the grooves that define the points of travel.  
         [0010]     Still further in accordance with a preferred embodiment of the present invention the linear motion element is adapted to cause the rotatable element to rotate when the portion of the linear motion element is positioned in the groove that is not one of the grooves that define the points of travel.  
         [0011]     Additionally the grooves comprise at least three grooves formed generally in a clover shape in the rotatable element.  
         [0012]     In accordance with a preferred embodiment of the present invention the rotatable element comprises a hook.  
         [0013]     Further in accordance with a preferred embodiment of the present invention the linear motion element comprises a link arm coupled with the rotatable element.  
         [0014]     Still further in accordance with a preferred embodiment of the present invention the link arm comprises a first pin at one end thereof that engages a slot formed in the linear motion element, and a second pin at a second end thereof receivable in any of the grooves formed in the rotatable element.  
         [0015]     Additionally in accordance with a preferred embodiment of the present invention the first pin is constrained to travel in a first channel, and the second pin is constrained to travel in a second channel.  
         [0016]     There is also provided in accordance with a preferred embodiment of the present invention a mechanical system including a rotatable element geometrically lockable at two points of travel, a linear motion element linked to the rotatable element, the linear motion element being adapted to move in response to a linear motion imparted thereto and to cause rotation of the rotatable element, and a linkage apparatus adapted to move the linear motion element in the linear motion. The system may include an element actuable by rotation of the rotatable element. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:  
         [0018]      FIGS. 1A-1E  are simplified front view illustrations of a rotary motion mechanism, constructed and operative in accordance with a preferred embodiment of the present invention, wherein the mechanism is progressively rotated from a first point of travel to a second point of travel, and the mechanism is geometrically locked in place at both points of travel; and  
         [0019]      FIGS. 2A-2E  are simplified pictorial illustrations of the rotary motion mechanism, corresponding respectively to  FIGS. 1A-1E . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     Reference is now made to  FIGS. 1A-1E  and  2 A- 2 E, which illustrate rotary motion mechanism  10 , constructed and operative in accordance with a preferred embodiment of the present invention.  
         [0021]     The rotary motion mechanism  10  may include a rotatable element  12 . Although the invention is not limited to the example illustrated in the figures, the rotatable element  12  may comprise a pivot  14  about which the rotatable element  12  may rotate, and two or more recesses or grooves offset from the pivot  14 . In the illustrated embodiment, three grooves  16 ,  17  and  18  are formed generally in a clover shape in the rotatable element  12 . The rotatable element  12  may comprise a hook  20 .  
         [0022]     The rotary motion mechanism  10  may include a linear motion element  22 . Although the invention is not limited to the example illustrated in the figures, the linear motion element  22  may comprise a tongue  24  that protrudes from a body  26  that pivots about a pivot  28 . A groove or slot  30  may be formed in body  26 .  
         [0023]     The linear motion element  22  may comprise a link arm  32 , which is preferably coupled with the rotatable element  12 . Although the invention is not limited to the example illustrated in the figures, the link arm  32  may comprise a bar with a first pin  34  at one end thereof that engages slot  30  of the linear motion element  22 , and another second pin  36  at another end thereof that engages any of the grooves  16 ,  17  or  18 . First pin  34  may be constrained to travel in a slot or first channel  38  ( FIGS. 1D and 1E ), and second pin  36  may be constrained to travel in a slot or second channel  40  ( FIGS. 1A, 1B  and  1 C). Channels  38  and  40  may be formed in a base or substrate  42 , which may also serve as the base for the pivots  14  and  28 .  
         [0024]     In  FIGS. 1A and 2A , second pin  36  (i.e., a portion of link arm  32 ) is fully received in groove  16 , thereby geometrically locking rotatable element  12 , that is, preventing rotation of rotatable element  12 . Thus, the rotary motion mechanism  10  is at a first point (for example, limit) of travel and geometrically locked in place.  
         [0025]     Reference is now made to  FIGS. 1B and 2B , which illustrate initial actuation of the rotary motion mechanism  10 . Tongue  24  may be lifted by a linkage apparatus  43  (shown only in  FIG. 1B  and omitted in the rest of the drawings for the sake of clarity) generally in the direction of an arrow  44 , thereby causing the linear motion element  22  to pivot about pivot  28  generally in the direction of an arrow  46 . Linkage apparatus  43  may comprise a rod, bar or other similar device, for example. Alternatively, tongue  24  may be lifted by a hand, finger or foot, for example. As the linear motion element  22  pivots, groove  30  pushes first pin  34  and the link arm  32  generally in the direction of an arrow  47  (along first channel  38 ). This causes second pin  36  to move out of groove  16 , along second channel  40 , towards a junction  48  of grooves  17  and  18 .  FIGS. 1B and 2B  show second pin  36  abutting against junction  48 . Until this point, rotatable element  12  has not yet started to rotate about pivot  14 .  
         [0026]     As tongue  24  continues to move in the direction of arrow  44 , and linear motion element  22  continues to pivot about pivot  28 , link arm  32  continues to move generally in the direction of arrow  47 . As shown in  FIGS. 1C and 2C , this urges second pin  36  into groove  17  and causes rotatable element  12  to rotate generally in the direction of an arrow  49  about pivot  14 .  
         [0027]     In  FIGS. 1D and 2D , tongue  24  continues to move in the direction of arrow  44 , and linear motion element  22  continues to pivot about pivot  28  in the direction of arrow  46 , second pin  36  continues to move along second channel  40  and rotatable element  12  continues to pivot about pivot  14  in the direction of arrow  49 . This motion moves second pin  36  out of groove  17  towards groove  18 .  
         [0028]     Finally, in  FIGS. 1E and 2E , tongue  24  continues to move in the direction of arrow  44 , and linear motion element  22  continues to pivot about pivot  28  in the direction of arrow  46 , until second pin  36  slides into groove  18 . Once this happens, second pin  36  is locked in groove  18 , thereby geometrically locking rotatable element  12 , that is, preventing further rotation of rotatable element  12 . Thus, the rotary motion mechanism  10  is at a second point (for example, limit) of travel and geometrically locked in place.  
         [0029]     The rotary motion mechanism  10  may be brought back to the orientation of  FIG. 1 , by moving tongue  24  generally in the direction opposite to arrow  44  and reversing the above-described process.  
         [0030]     The rotary motion mechanism  10  may be implemented in a mechanical system that comprises rotary and linear motion. The mechanical system may comprise a wide range of devices, and may include an element actuable by rotation of rotatable element  12 , such as the hook  20 , for example. For example, the rotary motion mechanism  10  may be part of a door lock system installed in a door, and hook  20  may be adapted to protrude from an escutcheon  60  into a door frame (not shown). Geometrically locking hook  20  at the second point of travel may substantially increase the locked security of the door. Other examples of devices may include a plowing mechanism, wherein it is desired to lock the plowing mechanism at two different points of travel, such as one orientation for plowing the ground and another orientation lifted above the ground. It is appreciated that these are just two examples of many other implementations of the rotary motion mechanism  10  of the invention.  
         [0031]     It will be appreciated by person skilled in the art that the present invention is not limited by what has been particularly shown and described herein above. Rather the scope of the present invention is defined only by the claims that follow: