US1672885A

US1672885A - Mechanical hammer

Info

Publication number: US1672885A
Application number: US37858A
Authority: US
Inventors: Goldschmidt Rudolf
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-06-17
Filing date: 1925-06-17
Publication date: 1928-06-12
Anticipated expiration: 1945-06-12

Description

June 12, 1928. 1,672,885

R. GOLDSCHMIDT MECHAN I CAL HAMMER Filed June 17, 1925 PYcssur-e of 5 brmg INVENTOR 3 I Rude/f Go/dsr rm/dfi 4 ITORNEV Patented June 12, 1928.

, UNITED STATES BUDOLF GOLDSCHMIDT, F CHABLOTTEI IBUBG, GEBIANY.

' uacnnmcn. maxim Application filed June 11, 1925. Serial Io. amas My invention has special relation to mechanical hammers and more particularly to those of the type set forth in my United States Letters Patent No. 1,386,329, issued 6 August 2, 1921, wherein is disclosed a very eflicient way of converting rotary motion into hammer action. The method comprises attaching to the hammer or tup one or more flyweights that are driven from a motor, and at the same time exercising a unidirectional force on the hammer preferably bythe pressure of a spring. The rotating flyweights develop centrifugal force imparting reciprocatory motion upon the tup, the unidirec- 1 tional force causin the hammer to deliver a stroke in a certain direction. I have discovered that certain definite relations exist between the centrifugal force with a variable direction and the unidirectional force of the spring. The foregoing relations are thesubject of this patent application.

In order that the invention may be more readily understood, reference is made the attached drawings, wherein:

Figure 1 shows a vertical section through a simple form of hammer;

Figs. 2, 3, 4 and 5 are diagrammatic views and curves relating to thedesign and working of the hammer.

The design of hammer shown as an example in Figs. 1 and 2 is not the most practical type, but is a simple form, and appears to be best for explaining the conditions being dealt with in this application.

In Figs. 1 and 2, 1 is the hammer or the tup which moves up and down and delivers the stroke upon the tool or anvil 10. 3 is a shaft which rotates in the bearings 4 in the tup and which is driven by the motor 9 through the medium of two clutches 6 and 7 and the flexible shaft 8. An eccentric fly weight 5 is fixed on the shaft 3. The described arrangement of drive has been chosen to allow maintenance of the rotation during 4 the reciprocatory movement of the tup 1, The tup is enclosed in the casing 2. A spring 11 is inserted between the upper port-ion of the casin and the tup.

Throu h the rotation of the flyweight 5 a centri gal force C is exercised upon the tup 1, the direction of C varying according tothe position of the flywei ht 5. However, on y the components of in the direction of the movement of the tup 1 is of import-ance at the present time. In this construction of the hammer a component at right angles to the movement of the tup would tend to cause a lateral shaking of the hammer and the casing. The casing may be fixed to a foundation or be so heav that the vibrations become negligible, or t e lateral motion may be compensated for. As descr bed in previous patents, particularly my Umted States Letters Patent No. 1,386,329, issued August. 2, 1921, these undesired forces can be compensated for.

The spring 11 exercises a unidirectional force P upon the tup in the direction of its stroke. It is important that the spring exercise this unidirectional force in every stage of the reciprocatory motion of the tup and in whatever position the hammer may be operating. That is to say the tool and ham mer ma be operated in an upward position, at wh1c 1 time the mass of the tup and the act on of gravity would be acting against the spring. If a sufficient blow is to be maintained in this position, the spring should have an initial tension or pressure 1 at least equal to the weight of the tup 1 including the fiyweight 5. Accordingly, the spring will exercise a force upon the tap at all times, even at the moment of impact with the tool 10. Therefore, it will be understood that P is the average pressure for the time of one working cycle, i. e., from one time of impact to the next time of impact.

When the tup 1 is moving upwardly under the action of the flyweights, the spring 11 is compressed, and its pressure increased directly proportional to the amount of the lift, as will be apparent from the diagram in Figure 3.

The ratio between the centrifugal force C of the flyweight 5 and the average pressure P of the spring 11 may be determined from the following formula derived with respect to the tri onometric functions of the angles between t e center line oftthe fiyweight and the line of tup motion at moments of im- Wherein 0 may be designated as the speed of the tup at the moment of the impact; at the angle between the center line of the flyweight at the moment of the impact (Figure l) and the line designating the to motion; M the total reciprocatory mass the tup; and w the angular velocity of the flyweight. B is the angle between the line designating the tup motion and the center line of the flyweight at the moment the tup is lifted. From a study of this formula it will be seen that the highest speed of 'u will be obtained if the two angles, av and B are equal. i. e., if the new cycle begins immediately after one is completed. The parts may be so proportioned by having the centrifugal force C equal to 'n' times the average pressure of the spring P.

\Vith this ratio of forces the tup will deliver one effective blow or stroke for each revolution of the flyweight. As the ratio of P times C becomes smaller. the stroke will become weaker and at 1:1, 5.1r is practically zero.

It has been discovered that if the pressure of the spring relative to the centrifugal force is still more reduced, an effective stroke is again delivered at the ratio PXC 1X21 but under these conditions only one effective stroke or blow is delivered for each two revolutions of the fiyweight. Similarly, one blow may be obtained for each three revolutions of the flyweight if the ratio of the spring pressure to the centrifugal force is arranged as PEG- 1:31: etc.

Figure 5 sets forth a curve of working conditions, the abscissae being the ratio C x P and the ordinate is the speed '0 of the tup when completing a blow. It will be noted that these curves have distinct peaks for a spring and weight in coaction similar to the well known resonance curves and therefore, a certain tolerance in the ratio C x P is permissible. It has been discovered that for most practical purposes this tolerance may be I claim: v

1. In a mechanical hammer, the combina tion with a casing, a tup within the casing having a flyweight journaled thereon and means for rotating said flyweight, of a. spring inserted between the casing and the end of said tup, and concentrically disposed about said fiyweight, said spring exercising an initial pressure corresponding to a force greater than the weight of the tup. I

2. In a mechanical hammer. the combination with a casing, a tap within said casing, means for reciprocating said tup, and a spring for exercising pressure upon the top of said tup, said spring having an initial compression pressure corresponding to a force greater than the weight of the tup and exercising a mean pressure during a cycle of operation with a tolerance of 3. In a mechanical hammer the combination with a casing, a reciprocatory tup within said casing for actuating a tool exteriorof said casing, a coil spring member disposed between the inner end of said tup and said casing, a flyweight journaled on the in- 'ner end of said tup and substantially en- RUDOLF GOLDSCHMID'T.