US2163847A

US2163847A - Impact indicator

Info

Publication number: US2163847A
Application number: US86012A
Authority: US
Inventors: Perrey Marcel Augustin Leon
Original assignee: Hauts Fourneaux de la Chiers SA
Current assignee: Hauts Fourneaux de la Chiers SA
Priority date: 1936-04-17
Filing date: 1936-06-18
Publication date: 1939-06-27
Anticipated expiration: 1956-06-27

Description

Patented June 27, 1939 UNITED STATES PATENT OFFICE HHPACT INDICATOR Hauts Fourneaux de la Chiers, Longwy (Meurthe et Moselle), France Application June 18, 1936, Serial No. 86,012 In France April 17, 1936 The direct measurement of the work of an impact member, such as a drop hammer, a projectile (shell), etc., moving at a high speed, gives rise to very great difliculties. The present invention relates to an apparatus eflecting such measurements with facility and accuracy.

The apparatus for carrying out the said process is essentially constituted by the combination: of a guide device rendered rigid with the-impact member subjected to the tests, an inertia member capable of freely moving in this device, a calibrated precision spring compressed (or stretched) by the displacement of the inertia member, a device recording the stroke of the inertia member, and, finally, a member limiting the upper position of the inertia member.

The apparatus forming the subject-matter oi the invention can receive various applications; it can be used every time, considering an impact member (drop hammer, projectile (shell), etc.) having a high speed, a negative or positive acceleration important relatively to this speed is to be measured.

In order that the invention may be more clearly understood, an application of the same to the particular case of the measurement of the work absorbed by the rupture of a rail by means of a drop hammer will be described hereinafter, by way of example only and without thereby limiting in any way the scope of the invention.

The accompanying drawing diagrammatically illustrates, by way of example only, a form of construction of the apparatus forming the subject-matter of the invention.

Fig. l is a section made on line I-I of Fig. 3 and shows the said apparatus.

Fig. 2 is a partial front view thereof.

Fig. 3 is a section made on line III-J11 of Fig. 2.

In the particular case which will be considered, it is desired to measure the number T of kilogrammeters absorbed by the rupture of a section of a rail resting on two bearings, said rupture being caused by the shock or impact of a drop hammer of known mass freely falling from a height also known.

As will be seen from the drawing, the appara-' tus which determines the value of T, by an indirect method, comprises the following elements:

1. A guide device, which is formed as a cylindrical tube I, secured in vertical position by any suitable means, for instance by screwing, to the upper part of the drop hammer M. This tube is provided, with a longitudinal slot 2.

2. A cylindrical inertia member 111 freely sliding in the tube I and guided in its movement by a projecting screw 3 sliding in the slot 2.

3. A precision spring 4, previously calibrated.

4. A device for recording the stroke or displacement of the inertia member. In the form of construction illustrated by way of example, this device is made as follows. On either side of the slot 2 are welded, throughout the length of the tube l, two

heel pieces

5, 5 in which

longitudinal slots

6, 6 are provided. A sheet I of thick paper, pressed against a backing sheet of metal, can be inserted in the

slots

6, 6, and then held stationary in the required position by means of four set screws 8. A tracing device 9, constituted for instance by a small pencil, slides in a housing provided for that purpose in the inertia member and a very light spring l0 always holds the point of the tracing device pressed against the recording paper.

5. A member limiting the upper position of the inertia member and constituted, in the example illustrated, by an internally screw threaded plug H which is screwed on the upper end of the tube l. The plug l l is screwed down only until it just contacts the upper end of the member M so that the force on the spring 4 is that due to member M only.

It is to be understood that the invention is not limited to the embodiment which has been,-.described and illustrated and that various modiflcations might be made in the details of construction of the apparatus without departing thereby from the scope of the invention; thus, for instance, the apparatus might be provided with a tension spring instead of a compression spring, a difierent recording device might be adopted, etc. Concerning this device, a. system can be adopted having a ruggedness consistent with the high speeds of impact, this giving the possibility of applying the process and apparatus forming the subject matter of the invention to the study and comparison of the efliciency of armour plates in function of the quality of steel employed. This particular application is moreover indicated by way of example only, and it is to be noted that the process and apparatus are of absolutely general application.

It is also to be understood that the dimensions of the inertia member and of the spring can vary between wide limits, in view of the adaptation oi the apparatus to the dimensions of the impact member on which it is intended to be fitted.

What I claim is:

1. An apparatus for the measurement of the work of an impact member travelling at high speed comprising an impact member, tubular guiding means having a slot therein carried by said impact member, an inertia member guided in said guiding means, an elastic member connecting said inertia member to said impact member, a tracing member carried by said inertia member and projecting through said slot and resilient means for maintaining the tracing member in contact with a tracing paper.

MARCEL AUGUSTIN LEON PERREY.