Abstract:
An efficient energy accumulation element comprising a compression spring which uses end caps and flexible rope to pre-compress the spring for using in actuators and other devices. The efficient energy accumulation element is independent of external surfaces or end construction of the spring. The accumulation and release of energy happens noiselessly.

Description:
FIELD OF THE INVENTION 
     The present invention relates to efficient energy accumulation element for actuators and other devices. 
     OBJECTIVE 
     The objective is to invent a mechanical energy accumulation element using springs which can be prepared for assembly with ease. 
     Another objective is to invent a mechanical energy accumulation element using a spring which can be deployed for accumulating higher energy and in which the energy accumulation is independent of the assembly construction. 
     BACKGROUND OF THE INVENTION 
     Accumulation and release of mechanical energy is a phenomenon deployed in several devices. Springs are one of the commonest elements used for this purpose. Both compression as well as extension springs are made use of. 
     For using compression springs, pre-compression is the first pre-requisite. Pre-compression is either achieved by surfaces external to the spring or by constraining the spring modularly. The first method viz. pre-compression by external surfaces requires skillful and time consuming assembly. 
     The second method viz. modular constraining is described, particularly for actuators in German patent DE 9314412, a U.S. Pat. No. 8,181,947 and also in patent Application WO2010/063514. In all these, the minimum length of cartridge is fixed. So even if the spring can be compressed to the solid length, the limitation of cartridge design does not allow. Further, these methods cannot be used efficiently for varying diameter compression springs which can be otherwise compressed up to coil thickness. 
     STATEMENT OF INVENTION 
     Our invention is an efficient energy accumulation compression spring assembled with a flexible yet sturdy rope entangled between two end caps, each cap being fixed at the respective end of the compression spring, allowing the spring to compress to any length up to solid. It is not driven by the stroke needed. 
     The length of the rope is shorter than the compression spring. The difference in length is according to the pre-compression or energy accumulation required. The end caps entrap the hammer or suitably shaped end of the rope. The spring is ready to be deployed without depending on external surface construction or even spring end construction. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows the efficient energy accumulation element of a progressively varying diameter compression spring in a pre-compressed state, ready to be assembled in devices like actuators etc. 
         FIG. 2  shows the efficient energy accumulation element of a constant diameter compression spring in pre-compressed state, ready to be assembled in devices like actuators etc. 
         FIG. 3  shows the efficient energy accumulation element in the compressed state, as it becomes during use in the device like actuators etc. 
         FIG. 4  shows preferred embodiment of construction of end cap. 
         FIG. 5  shows preferred embodiment of construction of flexible rope. 
         FIG. 6  shows a sectional view of an actuator using the efficient energy accumulation element of the compression spring. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     The preferred embodiment of an efficient energy accumulation compression spring assembled with a flexible yet sturdy rope will now be described in detail, with reference to the accompanying drawings. The terms and expressions which have been used here are merely for description and not for limitation. 
     Efficient Energy Accumulation Element ( 10 ) comprising a compression spring ( 5 ), whether having a constant diameter or a varying diameter is pre-compressed by using end caps ( 7 ,  8 ) and the flexible yet sturdy rope ( 6 ) having hammer shaped heads at each of its ends. The end caps ( 7 ,  8 ) have a diameter (D 1 ) slightly less than a corresponding outer diameter of the compression spring ( 5 ) so that the end caps ( 7 ,  8 ) are simply inserted in the compression spring ( 5 ) at spring ends. 
     Each of the end caps ( 7  or  8 ) have a through slot ( 11 ) through which the hammer shaped head ( 13 ) of the rope ( 6 ) is inserted inside the spring ( 5 ) and taken out from the end cap ( 7  or  8 ) at the other end. 
     Each of the end caps ( 7  or  8 ) have a blind slot ( 12 ) substantially at 90 degrees to the through slot ( 11 ) in which the hammer shaped heads ( 13 ) sits with interference and therefore needs to be pushed in with certain definite force such that it cannot come out without using a screw driver or a tool. The through slot ( 11 ) and the blind slot ( 12 ) are collectively called an opening construction. 
     The length ( 16 ) of the rope ( 6 ) is less than the length ( 17 ) of compression spring ( 5 ). 
     To assemble Efficient Energy accumulation element ( 10 ) with the compression spring ( 5 ), the compression spring is required to be held in a compressed state by any simple device like vice, etc. so that its length becomes less than the length of rope ( 16 ). A first hammer shaped head ( 13 ) of the rope is inserted from one of the end caps ( 7 ) and taken out from another end cap ( 8 ), while a second hammer shaped head follows, so that the first hammer shaped head and second hammer shaped head are present at each of the end caps. The Hammer shaped heads ( 13 ) i.e. the first hammer shaped head and the second hammer shaped head, within both the end caps ( 7 ) and ( 8 ) are turned so that the hammer shaped heads ( 13 ) sits over the blind slots ( 12 ). The compressed spring ( 5 ) is then released from the device used for holding it in the compressed state. Due to the compression spring ( 5 ) trying to regain its uncompressed state, both the hammer shaped heads ( 13 ), which were so far just partially engaged with the blind slots ( 12 ) now get fully trapped in the blind slot ( 12 ) due to its interfering construction. The compression spring remains compressed corresponding to the length difference between its free length and the effective length of the rope, as calculated &amp; suited for the application. This is also known as the pre-compressed state of the element ( 10 ). 
     One application described here is actuator ( 40 ). When a piston ( 30 ) moves in direction  31 -A, the efficient energy accumulation element ( 10 ) of the compression spring compresses as shown in  FIG. 3 , and accumulates energy. Since the rope ( 6 ) is flexible as shown in  FIG. 3 , the extent of cumulating energy is possible up to a solid length of the spring or as much as the spring permits. The action of accumulating and releasing energy is free from mechanical noise and does not need lubrication as there are no rubbing components 
     The construction of the through slot ( 11 ) and the blind slot ( 12 ) of the end caps ( 7 , 8 ) and ends ( 13 ) of flexible rope are possible in several ways such that they are assemble-able as described above or in any sequence and therefore the above embodiment is merely a preferred one and not limiting the invention. “Hammer” shape, in other words, is not a limitation of this design but is merely an embodiment and what is important is that the contour of the ends of rope and slots in the end caps are such that the rope can be passed thru’ the end cap ( 7  or  8 ) as well as trapped in the end cap ( 7  or  8 ) as required. 
     Also, the construction of end caps ( 7 ,  8 ) could be such as to entangle with the spring ends for facilitating assembly. 
     The flexible yet sturdy rope ( 6 ) can be of any material so long as it is flexible to allow spring compression without any limitation due to itself. The term “rope”, “flexible rope” and “flexible yet sturdy rope” are used interchangeably.