US1484490A - Mechanical hammer - Google Patents

Description

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R. GOLDscHMlD-r MECHANICAL HAMMER' Filed April 14. 1921 4 Sheets-Sha??l 4 Wg 4.5, `Ffgfg 74- agg/.5.

Patented Feb. i9, 1924.

nii-an srarns RUDOLF GOLDSCHMIDT, OF BERLIN, GERMANY, SSIGNOR T0 DET TEKNSKFZ FCWGS- AKTIESELSK :.:l OF ORDRUZP, CHARLOTTENLUND, DENMARK, A COMPANY F DEN- MECHANICAL HAMMER.

Application tiled April 14, 1921. Serial No. 461,446.

To all whom t may concern.:

Be it known that l, RUDOLF Gonnsoninn'r, a German citizen, resi ing at 45 Linden Allee, West End, Berlin, Germany, have 1ne vented new and useful improvements in Mechanical Hammers, of which the following is a specification.

This invention relates to mechanical hammers and consists essentially in effecting ic the storage of energy in the tup by the reaction of the bearings of an element or elements movable relatlvely to the tup.

ln order that the invention may be more clearly understood reference will hereinafter i be made to` the accompanying drawings whereon:

Fig. 1-0ld form-is a diagrammatic View of a known type of mechanical hammer.

Fig. 2 is a. side view partly in sect-ion 2c showing one form of the present invention. Fig. 8 is a side Aview partly in section taken at right angles to Fig. 2.,

Figs. 4, 5 and 6 are diagrammatic illustrations of the hammer shown in Fig. 2 in 2e three different positions.

Fig. 7 is a sectional view of a modied form of mechanical hammer or pile driver.

Fig. 8 illustrates a further modified construction of the present invention applied au to a hand hammer or percussive hand tool. Figs. 9 and 10 are detail sectional views of the mechanism shown in Fig. 8

Figure 11 is a sectional view showing a further modified construction of the imas proved mechanism, and Figure 12 is a sectional view on the line Z-Z of Figure 11.

Fig. 13 is a fragmentary view of the improved mechanism applied to a reciprocatory tup of a hammer and Fig. 14 is an end e View of the mechanism shown in Fig. 13.

Figs. 15 and 16 are detail views of the pin-and-slot mechanism employed in the mechanism shown in Figs. 13 and 14.

Referring to Fig. 1 which illustrates a 4.5 common form of actuating mechanism for the tup V of a hammer, driven by means of a crank A and connecting rod'B, it is usual to interpose a spring U between the crosshead of the connecting rod and the tup in 5e order to give the latter slight freedom of movement relative to the positive movement of the crosshead. The provision of a spring however presents structural difficulties, as

part of the power is absorbed by the spring instead of being imparted to the tup. rlhe construction is therefore always comparatively large and heavy and subject to considerable vibrations.

The object of the present invention is to drive the tup of the hammer by simple mechanical means so that it shall have sufficient freedom of movement and to provide an arrangement in which the highest possible velocity shall be attained at the momentwhen the 4blow takes place.

In order to attain this object the forces reacting on the crank bearing l (Fig. 1) are uti ized to drive the hammer. ing to the present invention and as shown in Fig. 2, the crank bearing K is mounted on the tup V which can reciprocate vertically between the guides C. At its upper end the tup V carries the crank A which is rotatable in the bearings K and driven by a spring Y. By means of a universal coupling and longitudinal flexible shaft, the driving mechanism does not impede the movement of the tup. The spring Y is wound up by the motor D. rThe function of the spring will be hereinafter `more fully described.

By means of the connecting rod B, the crank is connected toy a weight W' which is freely movable vertically in a. guide in the tup V. H represents an anvil on which a block T is to be forged. When the crank A. is rotated, the weight `W is reciprocated and reacts through the crank A upon the bearings K. As the bearings are movable with the tup V, the tup is thus` set in reciprocatory motion. lVithin certain limits of speed the operation will be as follows; reference being made to Figs. 4, 5 and 6:-

Assuming the tup V to be in its lowermost position and resting upon the work F and assuming that the weight W has passed its point of maximum Velocity fu, as in Fig. 4f, and that it is retarded by the force P1, then a reaction P2 will be produced in the crank 'bearing K, the reaction F2 being equal to the force P1. The reaction P2 raises the tup and varies in magnitude, reaching its maximum when the weight W has reached its uppermost position and is again moving downwardly (Fig. 5). 'l` he force F2 changes in direction when the weight W has passed its middle position (Fig. 6) thereafter till Accord- 1 I adjustable by means of a tooth if the tup is loaded not only by the force l of gravity but by other downwardly acting forces, such as a spring. In the case of hammers which are to operate horizontally or in a vertically upward direction, this spring serves not only to increase the force of the blow but also to absorb the recoil. y

Fig. 7 illustrates a resilient or spring` controlled hammer or pile driver. The driving shaft R mounted in the tup V actuates the weight W by means of an eccentric A and rod B. A spring X acts upon the tu wheel and gearing from an external pulley S2. A lower spring U is provided for moderating and regulating the force of the blow. Normally this spring is disposed so low down that the distance a is greater than the distance b, so that the s ring U is ineffective. If the height of t e spring U is adjusted by rotation of the wheel S2, part of the kinetic energy of the tup V will be taken up by the spring U and in the extreme position, the tup V will no lon er strike the pile T.

The spring X s ould be so arranged that it acts on the tup with a practically constant force. This may be attained by imparting to the spring such an initial compression that its force is only slightly altered on further compression. If the stroke for example is ten centimetres, a spring would be selected compressed by say one metre in length before insertion in the casin In the case of hand hammers aconstant orce is important as a spring of insufficient initial tension would lead to undesirable vibrations. ,Cranks and connecting rods are not alwa s the best means for actuating the weig t W. In the first place, on account of the vibrations in the bearings set up b the blows of the tu rof the hammer, the iameter of the shag; will generally require to be sogreat that the crank and connecting rod must be re laced by an eccentric. In such case in or er to suppress vibrations at right an les to the direction of the blow, the weig t W may be driven by means of two sets of eccentrics which rotate at the same angular velocity but in opposite directions.

Fig. y28 illustrates a hand hammer having 'l the aforesaid modifications. The tup V is direction.

guided in a casing C. R is a cross pin fixed on the tup and on which the eccentrics A2 and A2 rotate in the same direction. The eccentric A2 rotates thereon in the op osite These eccentrics`| are riven through gea E and F and a longitudinally mova le square shaft N from a coil spring Y which in turn receives its V and is.

to the eccentrics A2 and A2, the eccentrics B2, B2 B2 are compelled to turn (see Figs. 9 and 10) within the element W, the eccentric B2 rotating in the opposite direction to the eccentrics A2, B2 and B2. To equalize the forces acting on the element W, the eccentrics A2 and B2 are together equal in weight to the total mass of the eccentrics A2, A2, B2 and B2. The element'W is thus reciprocated by the eccentrics and does not require any special guiding means, other than its support on the eccentrics B2, B2 and B2. The operation will be more readily understood by reference to Figs. 9 and 10 which illustrate the position assumed when the eccentrics A2 and A2 have rotated through approximately 45 degrees from the vertical centre line. It will be seen that the eccentrics A2 and A2 each tend .to turn within its surrounding eccentric but that, in doing so, they react upon each other through the cross-pin R, this reaction compelling the eccentrics B2 and B2 to turn in the o p site directions to A2 and A2 respectively. Since B2 rotates in the opposite direction to B2 and B2, the element W is prevented from turning with any of the eccentrics B2, B2 or B2. The eccentrics are so adjusted on the cross-pin R that the parts of greater radius are always in line on the vertical centre line of the cross-pin (see Fig. 8) and consequently the reactions on the element W reach their maximum when the eccentrics pass over their upper and lower dead centres. As the eccentrics reciprocate with the element W, they supplement the actual wei ht of the latter, which may thus be relative y negiligible. M is a membrane closure for the interior of the casing C and against which the tu V is adapted to strike.

Various ot er mechanical means may be adopted for obtaining the relative movement between the element W and tup V, such as planet gearing, links and the like. For supplying lubricant and in order to reduce welght the axle Ris structed as a thin walled tu e.

Fi 13 to 16 illustrate a construction in l whic eccentrics A2 A2 B2 and B2 are employed without an element W. The eccentrics A2 and A2 are driven in oppositedirections by gearing E interposed between the eccentrics. The eccentrics B2 and B2 are caused to rotate about the eccentrics A2 and A2 b means of the cross shaped slots E2 in whic guide blocks or rollers E2 and E2 are movable, the latter bein fixed on arms E2 carried by the eccentrics 2 and B2. In Fig.

16 the eccentric B is turned through 45. w

referably conlll Instead of the pin-and-slot connection, the movement of the eccentrics B1 and B2 may be effectedby planet gearing or like means.

The eccentrics in Fig. 13 rotate upon a unilaterally fixed axle or journal R. thus avoiding the ldifficulty of forking the tup V as a supporting means.

The peripheries of the eccentrics B1 and B2 do not require to be circular. The necessary eccentricity of the centre of gravity of the masses however determines to some extent the shape of both eccentrics.

ln the construction shown in Figs. 13 to 16, the eccentrics A1 and B1 are together equal in weight to the eccentrics A2 and B2 taken together. Since A1 rotates in the opposite direction to A2 and since B1 and B2 must turn about A1 and A2 respectively in opposite directions, and furthermore, by reason ofthe eccentrics. being so adjusted that their greatest radii are in line vertically (as seen in Fig. 14), the eocentrics react on the cross-pin R and set the latter in vertical reciprocation.

Figs. 11 and 12 illustrate a construction having a hollow axle R upon which rotate eccentrics A1 and A2 having teeth engagin a. driving pinion E. The eccentrics A1 an A2kare thus driven in opposite directions. Pinions F1 and F2 are carried 'internally b eccentrics B1 and B2, the pinions F, and l 2 engaging internal teeth G, and-G2 on vthe hollow axle R. In this case, also, the

eccentrics B1 and B2 are rotatable on the eccentrics A1 and A2 respectively and are caused to rotate in opposite directions by the gearing F1, G, and F2, G2 and, as the greatest radii ofthe eccentrics are in line i vertically (as seen in Fig. 12) the reaction of the eccentrics on the axle R reciprocates thel latter, which carries the tup V.

The driving mechanism preferably comprises a spring Y (Figs. 2 and 8) which 1s continuously or intermittently wound up by means of a motor or by hand. The torque on the crank A (Fig. 2) or shaft E (Fig. 8) varies according to the degree of acceleration of the mass W and also ac- `cordin to the amplitude' of the stroke. Imme iately after the blow, considerable power is required to lift the tup. Consejuently in order to avoid strain on the prima mover or driving gear and shafts, the mechanism is driven by means of a spring such as a clock spring, which will Avary in angular velocity to such an extent as to revent shocks. Immediately after the bow,

ing the tup to a unidirectional force.

3. A mechanical hammer as specified in ,claim 1 provided with la spring acting in` a forward direction upon the tup.

4:. A mehcanical hammer as specified in claim 1 provided with a spring initially under considerable stress and acting in a forward direction upon the tup.

5. A mechanical hammer as specified in claim 1 in which the mechanism comprises eccentric driving gear.

6. A mechanical hammer comprisin a reciprocatory tup, an inner rotatably riven eccentric journaled on the tup and an outer eccentric mounted ou the inner eccentric.

7 A mechanical hammer comprising a reciprocatory tup, a plurality of inner oppositely driven eccentrics journaled on the tu and a plurality of outer eccentrics mounte on said inner eccentrics.

8. A mechanical hammer as specified in claim 6 having a weighted element supported by the outer eccentric.

9. A mechanical hammer as specified in claim 1 in which the mechanism imparts a rotary path to the cent-re of gravity of the movable element.

10. A mechanical hammer comprising a reciprocatory tup, a plurality of elements movable in relation thereto and mechanism journaled in said tu for actuating said elements in o posite directions to each other.

11. A mecliianical hammer as specified in claim 1 having a spring for resiliently driving said mehcanism.

12. A mechanical hammer as specified in claim 6 in which the inner eccentric is journaled on a cross pin fixed to the tup.

. 13. A mechanical hammeras specied in claim 6 in which the inner eccentric is journaled on a hollow cross in fixed to the tup.,

RUDOLF OLDSCHMIDT. Witnesses:

ARTHUR SCHoLY, Go'rrLmB IscH.

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