GB1568110A - Apparatus for testing springs and the like - Google Patents

Description

(54) APPARATUS FOR TESTING SPRINGS AND THE LIKE (71) We, ATELIERS METALLUR PIQUES DE SAINT URBAIN, of 32 rue Washington, 75008 Paris, France, a French Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement::- The main patent discloses apparatus for fatigue testing two springs or two groups of similar coil springs at the same time, the springs being arranged in linear opposition between two fixed parallel abutments against which one end of the springs or groups of springs rests and an intermediate member against which the other end of the springs or groups of springs rests, the intermediate member being displaceable in a linear reciprocating movement perpendicularly to the fixed abutments, the apparatus further comprising an eccentric rotatable means which is mounted on the intermediate member and is rotatable in a plane perpendicular to the fixed abut ments so as to cause the intermediate memher to effect a linear reciprocating movement at a frequency substantially equal to the natural frequency of the springs being tested.

This apparatus, based on the principle of resonance effects, though capable of testing very large springs designed for very heavy loads, requires only very moderate power ratings for performing such testing operations.

It has also been found that the same apparatus could be used for testing torsion bar springs and steel test bars at the cost of only minor modifications.

According to the present invention there is provided an apparatus as claimed in the main patent for testing torsion bars, or steel test bars, wherein a linear reciprocating movement at a frequency substantially equal to the natural oscillation frequency of the bars to be tested is imparted to the intermediate member which is connected to means for oscillating one end of the bars to be tested, means being provided for locking the other end of said bars against movement so that the linear reciprocating movements of said intermediate member will apply alternating stresses to the end of the bars to which said intermediate member is operatively connected.

The single Figure of the attached drawing illustrates diagrammatically in front elevational view the apparatus of the main patent but slightly modified for testing torsion bars.

The torsion bars to be tested are designated by the reference numerals 12 and 13 and have a fixed end locked in jaws 1 and 2 respectively, and an opposite end responsive to alternating torsion stresses transmitted thereto through movable jaws 4 and 5 rigidly connected to pinions 14 and 15, respectively, in constant meshing engagement with straight toothed racks 16, 17, respectively, rigidly connected to the intermediate member 3 for translational movement therewith. This member 3 is in sliding engagement with bearing surfaces 9, 10, respectively. An electric motor (not shown) is mounted on this intermediate member 3 for rotatably driving an arm 6 adapted to pivot in a plane perpendicular to said bearing surfaces 9 and 10.Slidably mounted on this arm 6 is a weight 11 whose outermost position along the arm is limited by a stop member 7 adapted to be locked in the desired position on said arm 6. The aforesaid bearing surfaces 9, 10 are formed on a central bracket capable of preventing any movements of said intermediate member 3 therein except linear movements in a direction at right angles to the axes of the torsion bars to be tested.

The above-described apparatus operates exactly like the one disclosed in the main patent.

Of course, the apparatus described hereinabove and illustrated in the accompanying drawing is given by way of example, not of limitation, since many modifications may be brought thereto without departing from the basic principles of the invention. Thus, more particularly, this apparatus may be constructed in the form of a laboratory apparatus for testing steel test-bars, for determining whether the metal has or not well-defined properties in view of its future applications, notably for manufacturing torsion bars.

THAT WE CLAIM IS:- 1. An apparatus as claimed in the main patent for testing torsion bars, or steel test bars, wherein a linear reciprocating movement at a frequency substantially equal to the natural oscillation frequency of the bars to be tested is imparted to the intermediate member which is connected to means for oscillating one end of the bars to be tested, means being provided for locking the other end of said bars against movement so that the linear reciprocating movements of said intermediate member will apply alternating stresses to the end of the bars to which said intermediate member is operatively connected.

2. An apparatus as claimed in claim 1, wherein the means for locking the other end of the bars to be tested comprise jaws and wherein the means for oscillating the one end of the bars to be tested comprise movable jaws which are rigidly connected to pinions kept in constant meshing engagement with racks which are rigidly connected to the intermediate member.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. manufacturing torsion bars. THAT WE CLAIM IS:-

1. An apparatus as claimed in the main patent for testing torsion bars, or steel test bars, wherein a linear reciprocating movement at a frequency substantially equal to the natural oscillation frequency of the bars to be tested is imparted to the intermediate member which is connected to means for oscillating one end of the bars to be tested, means being provided for locking the other end of said bars against movement so that the linear reciprocating movements of said intermediate member will apply alternating stresses to the end of the bars to which said intermediate member is operatively connected.

2. An apparatus as claimed in claim 1, wherein the means for locking the other end of the bars to be tested comprise jaws and wherein the means for oscillating the one end of the bars to be tested comprise movable jaws which are rigidly connected to pinions kept in constant meshing engagement with racks which are rigidly connected to the intermediate member.