Суханов Владимир Николаевич : другие произведения.

Balanced hinge-lever mechanism

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  • Аннотация:
    Mechanism relates to plane hinged (lever) mechanisms and can be used for cranes design

   The author Vladimir Sukhanov 2002, 2003
   Translated by Valentina Sukhanova from Russian

Balanced hinge-lever mechanism

   Mechanism relates to plane hinged (lever) mechanisms and can be used for cranes design.

   The well known lever as a simple mechanism is a device in which a smaller force balances a large force. The lever has a fulcrum and two points where force is applied.

The lever is balanced if the vector sum of moments of forces acting on it equals zero.

Pa - Qb = 0,

   where a also b are arm of forces P and Q (see Fig. 1a)
In this case balance pivot is located between points of application of acting on the lever forces P and Q.

If two forces P and Q are applied to the lever on one side from fulcrum then they must be directed to different sides for their balance (see Fig. 1b).

     Mechanism 1 [Владимир Суханов] Mechanism 1b [Владимир Суханов]

Fig. 1a                 Fig. 1b

   Forces, applied on one side from fulcrum, can be directed also to one side for their balance. For this each force must have its section of the lever (its arm) between the point of application and the fulcrum and also on the fulcrum, the arms must be connected through a transmission gear, for example, one step of cog mechanism (CM). In this case rule of lever works see on Fig. 2.

Mechanism 2 [Владимир Суханов]

Fig. 2

   The cog mechanism (CM) must have a gear ratio equal to one, and also angles between the arms a and b and direction of the forces P and Q respectively must be equal.

   A new mechanism is proposed in which the forces P and Q are applied to the lever with two links 1 and 2 (see Fig. 3).

Mechanism 3 [Владимир Суханов]

Fig. 3

   The first link 1 of the lever with arm a and for force P freely rotates on hinge 3 of fulcrum 4. The second link 2 of the lever with arm b for force Q revolves on hinge 5 of the free end of link 1. One axle with hinge 5 revolves cog-wheel 6 to which is fixed link 2. Cog-wheel 6 is connected with cog-wheel 7 by a chain. Cog-wheel 7 is on one axle with hinge 3 and is fixed on fulcrum 4.

   The diameter of wheel 7 is in twice the diameter of wheel 6. The length of the arm is b = a + x, where x is length of link 1. Link 1 forms angle Alpha [Владимир Суханов] with the horizontal. Link 2 forms angle Beta [Владимир Суханов] with the horizontal. The sum of the angles is 90o (Alpha [Владимир Суханов]+Beta [Владимир Суханов]= of 90o). These conditions provide a balance of forces P and Q, with their equality despite the fact that they are directed to one side and are applied on the same side of the fulcrum.

   The trajectory of motion of the point of application of force Q is elliptical.

   The special feature of the mechanism on Fig. 3 in comparison with the lever on Fig. 2, consists in the fact that the forces which are located on one side of the fulcrum and directed toward one side, balance each other. In the proposed new mechanism, one of the arms is attached not to its base, but to the point of application of force of the other arm (action of transmission gear remains). Then we have a variety of lever, whose forces have one direction and are applied from one side from fulcrum. This is impossible from the point of view of common sense but the mechanism is very simple.

   Claim for this invention N 4130878/08 was noted on the mechanism in 1987, but acceptance of the solution but the author was refused by the branch patent appraisal/review OF VNIIGPE (ALL-UNION SCIENTIFIC RESEARCH INSTITUTE OF THE STATE PATENT EXAMINATION). The matter reached the expert council, but in their opinion which was tainted by strong cinematic superstitions and traditional prejudices, they did not believe the mechanism would work. Their "such cannot be" opinion prevailed.

   The balanced hinge-lever mechanism is represented on Fig. 3.

   For heavily loaded manipulators, role of the chain transmission can make cog mechanism with wheels 8, 9 and 10 (see Fig. 4).
   The diameter of wheel 8 is twice diameter of wheel 10. Diameter of wheel 9 is commensurate with diameters of wheels 8 and 10. All remaining conditions and proportions of this mechanism are analogous to the mechanism on Fig. 3.
   A hydraulic mechanism is possible. Simplicity of its construction and smaller mass which, in comparison with the mechanisms on Fig. 3 and 4, can make its competitive with similar devices (see Fig. 5).

   Mechanism 4 [Владимир Суханов] Mechanism 5 [Владимир Суханов]

 

Fig. 4                 Fig. 5

   In the hydraulic mechanism, a working hydraulic cylinder 11 from hydraulic pump with the instrument board displaces links 1 and 2 of the manipulators. In this case hydraulic cylinder 12 between base 4 and link 1 is connected to hydraulic cylinder 13 between links 1 and 2. Displacement of the rod in cylinder 12 causes an equal displacement of the rod in cylinder 13. The remaining conditions of work of the manipulator are analogous to the manipulator on Fig. 3.

   This device is developed in the following manner: If we proposed a balanced mechanism to represent one "link" of variable length, and, to it by a proposed technical solution, add a second similar "link", then we will obtain a balanced mechanism capable of moving the point of application of force Q not only along the trajectory of the ellipsis, but in the plane where links 1 and 2 are located.

   One example of this device with a balanced mechanism working in a plane is shown on Fig. 6.

Mechanism 6 [Владимир Суханов]

Fig 6

   Number 8 is the location of pantograph or other mechanism links, which ensures horizontal balanced displacement in space. The pantograph with link 8 ensures horizontal displacement of the balanced mechanism on Fig. 3. Links of this mechanism are 1 and 2.

   Link 2 is connected motionlessly to base 4 by means of a flexible shaft or chain transmission with gear ratio 1:2. In this case link 2 is connected to the shaft (transfer) in place for axle 5, and the transfer is connected to base 4 in place of fulcrum 3.

   This is not the only solution of the balanced manipulator. Similar types of mechanisms let us increase the EFFICIENCY of 'one-armed" manipulators. Energy in them will be spent only on overcoming of frictional forces in hinges and on the accomplishment of useful work.

   if manipulator from Fig. 3 (either 4 or 5) is placed on a load cart of a bridge crane (or trestle crane) so that its boom from links 1 and 2 can make vertical displacements in zones of inaccessibility for the load cart with a hoist of traditional scheme.

   A proposed manipulator can be used for the design of trestle cranes.

   The EFFICIENCY of this manipulator approaches 100%. Losses are caused by friction in hinges 3 and 5, losses which approach zero. For horizontal displacement, no work is spent on lift and descent of links 1 and 2, since they are balanced mutually.

   It was registered in VNTIC, 19 April of 2002 years under number 72200200011 and published in the bulletin of the VNTIC "Ideas. Hypothesises. Solutions" N 2, 2002 years.
   The article was also published in the book "Inventive Creation" in Russian language in 2003.

   Copyright - Vladimir Sukhanov 2002, 2003
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