US1400019A - Spring, particularly for use in percussion-tools - Google Patents

Description

M. L. BRAMSON.

SPRING, PARTICULARLY FOR USE IN PERCUSSION TOOLS.

APPLICATION FILED NOV-2, 1920.

Patented Dec. 13, 1921.

. UNETFD STATES ATENT orricn.

MOGENS LOUIS BRAMS ON, 0F STAFFORD, ENGLAND.

SPRING, PARTICULARLY FOR USE IN PERCUSSION-TOOLS.

Specification of Letters latent.

Application filed November 2, 1920. Serial No. 421,405. 7

2, 1920; Norway Sept. 30, 1920; Spain Oct.v

5, 1920; Sweden Oct. 1,1920) of which the following is a specification.

This invention relates to resonators. In many instances and particularly in the case of percussion tools it is necessary to suspend a reciprocating mass between springs so arranged and adjusted that a condition of resonance is established between the mass and the springs. v q

Hitherto this has been effected by suspending the mass between metal springs of suitable form but it has been found that in percussion tools for instance, where the mass is subjected to a high rate of reciprocation the springs frequently break.

vVe have proved by experience that it is possible to substitute for these metallic sprin s, e ther springs formed or constituted by liquid columns or capacities and the desired resonance conditions can be obtained by adjusting the respective areas upon which the liquid'operates, and the volumes of the capacities or springs to. fulfil the conditions requisite for a resonator.

The underlying principle of the present invention is the substitutionfor the metallic springs hitherto employed, liquid springs, and the invention consists broadly in suspending the reciprocating mass between columns of liquid.

It follows that the invention depends for its success upon the fact that liquidsare not incompressible but elastic.

Although capable of application to other uses where it is required to provide a spring suspension for a reciprocating mass the invention is particularly applicable to percussion tools for use in wave transmission systems, the general principles of which are now well known and are outlined in the specification of Letters Patent No. 9029 of 1913.

In carrying the invention into practice,

three fundamental conditions must be ob served: Firstly, there must be resonance be-.

tween the reciprocating mass and the capacities. That is to say, the reciprocating mass and the capacities must be in a state of resonance and satisfy the equation L0a =1 when Lzco-etlicient of inertia, C co-efli- Patented Dee.13, 1921.

cient of capacity and a the angular ve l locity in radians per second. Secondly, the

mean pressure in the linemust be balancedby the maximum pressure on the front capacity acting on their respective areas.

This second condition is only strictly true in cases where there isno initial pressure inv the system but where there is an initial pressure, .as is usually the case in practice,

this initial pressure has to be taken into account and it is a more accurate statement for all conditions to say that the force exerted by the mean pressure in the line acting on its area of the reciprocating mass plus the force exerted by the minimum pressure in the rear capacity acting on its area of the reciprocating mass must equal the force ex! erted by the maximum pressure 1n the front. capacity acting 011 its area of the IeClPI'OCELlE ing mass. I v

Thlrdly, the mean pressure in the line and the pressures in the two capacities must all be equal when the apparatus is in operation.'

The first and second of these conditions is in accordance with the same prlnciples as when metallic springs are used, and are obtained in the same way. The third condition is necessary because leakage will, in any case, make the mean pressures equalandtherefore ifthey are not equal when the appa ratus is working, it will cease to work when they are.

In the accompanying drawing vice illustrating my invention diagrammatically. q

Fig. 2 is a longitudinal diagrammatic sec tion illustrating the application of this invention to a riveting hammer.

Referring to the drawings 66 the reciprocating mass, 6 designates the i11- let or line connection from a wave transmission generator, 6 is the area of the reciprocating mass (1 upon which the pressure in the line operates, 0 is the front capacity, the annulus c is the area upon which the pressure in this front capacity acts, d is the rear capacity and the annulus d is the area designates x Figure 1 is a longitudinal section of a de pacity acts.

' is .57 of the force exerted by the maximum mean value.

1n the forward direction into the front capressure in'the frontcapacity 0 acting on the annulus 0 The operation may be stated in popular language follows :The pressure waves enter at the inlet or line connection 2) and the pressure rises and falls from zero to maximum in accordance with a given frequency in the manner now well known. The blow commences to be struck, or, in other words,

the energy commences to be imparted when the reciprocat'ed mass at reaches its foremost positionindicated in the diagram by the dotted line. This occurs when the pressure in the line b has risen from Zero to its mean pressure. This blow continues, or mother words, the energy continues to be imparted until the pressure in the line b has risen to its maximum value and fallen again to its The movement of the mass a pacity c has caused the pressure in the caparit c to rise owing to the fact that there is no displacement of theliquid, and when the line pressure falls to its mean value the pressure in the capacity 0 acting on the annulus c exerts a force which just balances the opposing force exerted by the mean pressure in the line b acting on the area Z2 plus the force exerted by the pressure in the rear capacity cl acting on the annulus.

Assuming that there is no initial pressure in the system there will be nopr'essure in the capacity (Z at this instant but assuming that there is 'an initial pressure in the system the pressure in the capacity (Z will be this initial pressure only, '5; e. the pressure in the capaci'ty (i will be at its minimum value.

Immediately the line pressure at'b falls below its mean value it follows that the force exertk'a'd upon the reciprocating mass in It will be understood that the above represents the action of one period in the wave and the action is repeated with the wave frequency. That is to say, assuming a wave frequency of 2,300 periods per minute, which is a usual frequency, the action will be repeated 2,300 times per minute. The appli-,

erating as springs so arranged and adjusted that'a condition of resonance is established between the mass'and the liquid springs substantially as specified.

2. A resonator comprising a reciprocating mass having an area subject to the pressure of a liquid column in one direction and an area subject to the pressure of a liquid column in the opposite direction the respective areas and pressures being so related that a condition of resonance is established between the mass and the liquid columns which opcrate as springs substantially as specified.

8. A percussion device comprising a reciprocating mass adapted periodically to impart energy at one position and to have en ergy periodically imparted to it at another position,'and liquid capacities between which the mass 1s suspended the arrangement belng such that the rec1prooat1ng mass and the springs constituted by the liquid columns are in resonance substantially as specified.

4. A wave transmission percussion device 7 comprising a reciprocating mass adapted periodicallyto impart energy at one posltion and to be subject to the alternating'pressure of a wave transmission generator at another posltion, and a front capacity and a rear ca pacity between which the mass is mounted in spring suspension so that the mass and the springs constituted by the capacities are in resonance substantially as specified.

Signed at London, England, this twentieth day of October, 1920.

MOGENS LOUIS BRAlWSON.

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