US1879464A - Piano hammer forming machine - Google Patents

Description

P 27, 2- r w. .1. PFRIEMER 1,379,454

PIANO HAMMER FORMING MACHINE Filed Jan. 23; 1931- a Shqets-Shet 1 wnmzssr-zs 5:402 750 w WZ/[am rzihzer ATTORNEY P' 91 w. J. PFRIEMER 1,879,464

PIANO HAMMER FORMING MACHINE Filed Jan. 23, 1931 I5 Sheets-Sheet 2 F x I 6' W IT lTII 7y INVENTOR WITNESSES WZZZmm If meme;-

1x BY ATTORNEY p 1932- w. J. PFRIEMER 1,879,464

PIANO HAMMER FORMING MACHINE Fi led Jan. 25, 1931 s Sheets-Sheet s INVENTQR WITNESSES I Wig/67716! ATTORNEY Patented Sept. 27, 1932,

UNITED STATES ATENT" OFFICE WILLIAM. J. PFRIEMER, OF BELVIDERE, NEW JERSEY PIANO HAMMER romaine MACHINE 7 Application filed January 23, 1931. Serial No. 510,838.

vide a piano hammer forming machine.

wherein piano hammer strips may be made of difierenthardnesses so that the hammers when placed in a piano may correspond with the particular work they are to do.

A further object, more specifically, is to provide a piano hammer forming machine wherein the parts of the piano strip are pressed firmly together by suitable dies and associated with means for locking the dies in their clamped position so that they may be removed from the machine and a new one substituted, said removal not interfering with the fixed clamping position of the various dies.

An additional object of the invention is to provide a machine which will press a section or an entire piano hammer strip into proper shape, the same being associated with dies and locking means which are removable from the machine after having been brought to a locking position, whereby the successive sections or complete strip may be formed without waiting for the glue to dry.

In the accompanying drawings Figure 1 is a front view of a piano hammer forming machine disclosing an embodiment of the invention;

Figure 2 is a side view of the machine shown in Figure 1; v

Figure 3 is a fragmentary view showing the dies and associated parts illustrated in Figure 1, but illustrating the same in a closed and locked position ready to be removed from the pressing machine;

Figure 4 is a view similar to Figure 3 but showing the parts about to be removed;

Figure 5 is a perspective view of the dies, locks therefor, and hammer strip or hammer section shown in Figure .4, the same being removed.

Referring to the accompanying drawings by numerals, 1 indicates the frame of the pressing machine which may be provided with suitable bars, arms and other members to carry the various moving parts. Asillustrated in Figures 1 and 2, frame 1 includes a pair of crane members 2which in turn carry therespective sliding threaded compression rods 3. As both of these rods and associated parts are identical, the description of one will apply to both. 'As illustrated in Figure 2 a link 4-is piv ,otally mounted at 5 on the crane member 2, and pivotally connected at 6'with a lever 7.

The pin or other means 8 pivotally connects lever 7 with the upper end of rod-3, while a pin or other means 9 pivotally connects one end of lever 7 with a piston rod 10 of a suitable piston arranged in the air cylinder 11; This cylinder has ports at points 12 and 13, said ports being alternately outlet and in let ports. Port 12 is connected by pipe 14 witha foot valve 15, while port 13is connected by pipe 16 to foot valve 15. An air supply pipe 17 isalso connected to the foot valve 15, said pipe ,17 being connected to an air compression pump or tank where a continuous supply of compressed air is provided. During theoperation of the machine, as hereinafter described, it will be noted that air passing from pipe 17 .will pass through suitable ports in the foot valve 15 and will alternately pass through pipes 14 and 16 according to the direction of movement of the piston rod 10. For instance, by depressing the foot pedal 18 air will be admitted from pipe 17 to pipe 14. When this occurs air will pass into the bottom of cylinder 11 and the. air 35 above the piston will pass out of the top through port 12 and pipe 14, there being a suitable exhaust valve in the valve 15. Valve 15 is so constructed that after having been once depressed it remains in that position until moved upwardly to a central or, neutral position, .or until the foot pedal 19 is de pressed, whereupon the reverse action takes place, namely, air will pass from pipe 17 to pipe 14 and from thence into cylinder 11 at the top, whereby the piston rod 10 and associated parts will be moved downwardly so that the parts will assume the position shown in Figure 2.

While this is taking place air will be exi reducing valvesare adjusted accordingly and hausted through pipe 16. The foot valve 15 is an old and well known type and therefore the details thereof have not been set forth in the drawings. The particular valve 15 disclosed in the drawings is a Logan foot control operating valve known as Model H, and manufactured by the Logansport Machine Co. of KLogansport, Indiana. 'This valve operates as above set forth. The desirability of using the valve just mentioned is that when one pedal is forced down' the piston rod 10 is moved upwardly and held upwardly, and moved down and held down wardly until released, .when the other pedal is operated. The twocylinders 11 are'con-' nected together as shown in Figure 1 so as to be operated simultaneouslyby the single foot pedal 15. -Variations in the pressure in the two cylinders is secured through the use of reducing valves'16 and 16" located in air feed lines of the respective cylinders- By reason of this structure,-as one cylinder is to operate at a given pressure and the other cylinderat'a slightly higher pressure. The, two

then will automatically supply the pressure desired from thesamesource. of compressed air supply.

In the accompanyingdrawings the strip i 20 is shown as being 14 inches long, but it length was usually about 40 inches and in view of the fact that it was pressed into a die all at one time, the resulting structure had the same characteristics throughout due to the rigid and inflexible pressure of the dies used. 7 1

By providing three sections for a piano one section may be made so that the hammer heads will be hard, a second section may be made so 7 that the heads will be of a medium hardness,

and the third section so that the heads willbe comparatively yielding, and each section in varying'degrees from one end to the other. In this way the various hammer heads provided for a piano and cut from these three sections will answer the requirements of musicians and will cause the strings of a piano to vibrate in a proper manner and with proper tone effects. I l

Asshown in Figure 1 the respective rods 3 slide loosely through sleeves 22 and carry stop nuts 21 for limiting the movement of the rods 'in one direction. The lower end of each of the rods 3 is supplied with a link 23. Each of these links has its lower end pivotally connected with a bar 24 formed with a depending flange 25. The formation of this flange 25 results in a shoulder 26 and also a notch 27. Notch 27 is adapted to receive a clamping plate 28 which is suspended by pins 29, said plate being adapted to clamp the base 30 of the piano hammer section 31 firmly in the notch. This is accomplished by reason of a swinging catch 32 at each end of the bar 24, said catches having suitably formed slots 33 adapted to fit over the respective pins 34 to draw the clamping plate 28 tightly against the base 30, as illustrated in Figure 3. By reason of-these catches 32 base 30 may be quickly and easily released at any time.

As shown in the drawings the under felt 35 has been secured to the wooden strip and the outer felt 36 is about to be applied, or is applied, as shown in Figures 3 to 5, inclusive. However, as shown in these figures the glue is not yet dry and consequently the dies 37 and 38 are held rigidly in their clamped position by suitable cams 39.

In the formation of the complete hammer head section the parts are positioned as shown in Figures 1 and 2 and one pedal of the foot valve 15 is operated, whereupon air at a certain pressure isdirected into the lower part of each of the cylinders 11. This will cause both of the rods 3 to move downwardly and move at the same pressure when the same air supply is being used. This downward pressure in the two cylinders 11 is regulated to a predetermined degree by the reducing valves 16 and 16". In the feed lines of the respective cylinders one of the reducing valves 16 or 16 is set for a lower pressure and the reducing valve so set will first out off the air supply for its cylinder at the degree of pressure for which it is set and then the other cylinder with a higher degree of pressure will shutoif the supply as soon as the higher pressure has been reached. If desired, gauges could be connected with the respective pipes to indicate or showthe degree of pressure in each cylinder. A die 40 is arranged immediately beneath the center of the upper felt 36 and this die is formed with a depressed portion 41, whereby part of the felt 36 will be pressed into the depression 41 and the ends 42 and 43 will be tilted upwardly appreciably.

From Figure 1 it will be seen that springs 44 and 45 are connected to the respective rods 3 and to the bar 24 to assist in centering the bar 24 but will not prevent the respective rods 3 functioning to exert the desired pressure on the outer felt 36. It will thus be noted that springs 44 and 45 are anchored to the lower ends of the rods 3 and are also anchored to the bar 24. This will prevent any accidental swinging movement of this bar. If it were not for these springs, the links 23would allow a swinging movement before the parts contacted with the felt 3.6. These" springs-preventa longi tudinal movement of the bar 24 but will not prevent the rods 3 to function as described.

After the inner felt and the wooden support therefor have been moved downwardly,

as above described, the respective pedals 46 and 47 are depressed, whereupon mechanism outer surface of the outer felt 36 in the cor-" rect shape, as shown in Figures 3 and 4. As these diesmovetoward each other under pressure above specified, which may be lbs. or more, the cams or wedge cams 39 will automatically function to lock the dies against return movement. Each of these cams is formed as shown in Figure 4 and consist of a table-shaped body 48 and 2. turned up end 49 associated with a spring 50, which spring gives the cams a tendency to moveinwardly against the inclined or cam surface 51 of the die 38. Die 37 is secured by a bolt, rivet or other means 52 rigidly to the respective bars 53 and 54. After the parts have been moved to the clamped position, as shown in Figure 3, the dies cannot be retracted until the cams 39 have been pulled outwardly. :By reason of this fact the dies are locked together and the next operation is to release the catches 32, as shown in Figure 4, whereupon the clamping plate 28 will become loose. Dies 37 and 38, and the piano hammer. section and associated parts are then bodily removed and laid aside, as shown in Figure 5. They are left in this position for six hours or longer to permit the adhesive to dry.

Heretofore the entire clamping operation used in clamping the parts together necessitated allowing theparts to remain together so that only a few hammer head strips could be made in a day by a given machine. By the operation just described a large number may be made in one day. i In fact, the operation just described can be done in a few moments and then the complete strip laid asideuntil it is completely dry, after which it is cut into the desired lengths to produce the desired hammer heads.

The air in cylinders 11 is preferably at a considerably higher pressure than in the cyl-' inders 54 and 55. The air pressure in cylinders 54 and 55 produces a constant lateral pressure against the head being formed,

while the difference in pressure in the respective cylinders 11 causes a vertical pressure which is greater at one end than at the other in order to secure different degrees of hard ness in the finished head. The foot valve 46 is similar to the foot valve 15 exceptthat it has only one pedal 47 because the cylinders 54 and 55 automatically exhaust when the pedals are released. The valve 46 may be of any desired. kind to accomplish this result a but thatshown in the accompanying drawings is the Logan foot'controlled operating valve, Model G, manufactured by the L0". gansport Machine Company of Logansport, Indiana. WVhen the pedal 47 is depressed air will be supplied through air supply pipe 58 to the respective inlet ports 60 and 61. Pipe 58 may be connectedtothe same supply that, the pipe 17 is connected or may be connected to a different supply. It will be understood that piston rods-56. and 57 are connected to.

suitable pistons adapted. to' reciprocate/in cylinders 54 and 55.. Piston rods 56 and 57 are provided each with abifurcated end 62 which carries a. pivotal pin 63, while on this pin are pivotally mounted links 64 :and 65. The upper end of these links are respectively connected to thelower ends of the levers 66 and 67, and these levers arepivotally mounted on frame 1 at points 68 and 69. The ex treme upper ends of levers 66 and 67 are provided with slots 70 and 71accommodating the respective pins and 81, these pins ex tending through the respective sliding blocks 82 and 83, said blocks beingslidingly dovetailed in the supporting block 84 which is preferably rigidly secured to frame 1.

From F igure2 it will be seen that the blocks 82 and 83 are notched or partly bifurcated,' and the ends of'the levers 66 and 67 extend into these notches or partial bifurcations. In this way the levers 66 and 67 may move the blocks 82 and 83 toward and from each other and consequently may move the dies 37 and 38 to a clamping position as shown in Figure 3. It is tobe understood that when pedal 46 is lowered it is held down by'the feet of the operator, but this condition is only temporary because the parts will quickly move the dies over to the clamping position and the cams 39 will lock the dies against return movement. As soon as the dies have been moved over to their correct clamping position the piston rods 56 and 57 are released and automatically the foot valve 46 will permit the air to escape through the ports 60 and 61 and permit air to enter the cylinders through ports 85 and 86. i

' By this structure the blocks 82 and 83 are positively moved to the position shown in Figure 2. Ainewset of dies 37 and 38 then may be added and the operation repeated. From Figure 2 it will be noted that the cylinders 11 are pivotally mounted so as to swing as the leverand associated parts operate. It will, of course, be understood that the glue or other adhesive is applied for holding the inner felt 35 in place and also for holding the outer felt 36 in place after it has been folded and pressed and leftto dry, as illustrated in Figure 5. V

j What I claim is- 1. A" piano hammer forming machine including a pair of clamping dies for clamping the heads of the piano hammer strip, said dies being positioned to slide toward and from each other, sliding wedge cams for locking'said dies in clamping position, and means'for moving the dies to a clamping position, said wedge cams automatically engaging and locking said dies against a return movement, said wedge cams functioning at all times during the movement of said dies, said dies 1.being bodily removable from the last mentioned means while in a clamping position, whereby the operation may be repeated in quick succession.

2. In a device-for forming piano hammer head strips including a'pair of sliding-dies for clamping the hammer head strips, guiding bars for guiding the sliding movement of said dies, a cam for each guiding bar carried by one of said'dies for locking the dies in a clamping position,said wedge cams functioning at any point along the respective guide bars, a pair of sliding iaws for moving the dies to a clamping position while the dies are functioning, said dies being bodily removable with thestrip after said dies have been moved to a clamping position and while in a clamping position. i

3. A piano hammer forming machine including a press formed with a vertical recip rocating power actuated bar and a plurality of pairs of horizontally sliding power actuated clamping members, means for clamping the base of a piano strip in said vertical bar, a pair of dies positioned to be moved toward each other by said clamping members, whereby an outer felt may be clamped tightly against a proper place on said base, a pair of guide bars for said dies, one of said dies being connected to said guide bars while the other die is slidable thereon, and means connected with the die which is slidably mounted on the guide bar for automatically locking said die. against a return movement, said dies and means for clamping the same together being bodily removable with the piano hammer head strip while in a clamping position.

4. In a piano hammer forming machine a press formed with means for receiving and moving a piano hammer head strip base with its inner felt to a given position, a pair of removable dies, a pair of guiding bars each connected at one end to one of said dies and each slidingly extending through the other die, the said last mentioned die being hollow, means operated by the press for moving the dies to a clamping position, said dies acting to clamp the outer felt around said inner felt, said dies being bodily removable when said clamping means has been released and while intheir clamping position, and cam means carried by said hollow die and project-' ing therein for automatically locking said dies in theclamping position i 4 5.- In a piano hammer forming machine a press provided with means for removably receiving the wooden base of a piano hammer headstrip, a pair of dies removably mounted on the machine for clamping the outer felt in position against said base, a pair of sliding blocks operated by said machine for moving said dies to aclamping position, a pair of guiding bars for said dies, one of said dies being hollow and cam means for automatically locking said dies in clamping position whereby when said blocks'have been moved to a released position and said base released from said press, said dies, felts and base are capable of being removed while the dies are in their locked position and placed at one side until the parts have set said cam means including a cam slidingly mounted on each of said guiding bars with one end extending into said hollow die and a spring acting on each cam for pressing the cam continually against the hollow die for locking the dies against a return movement.

6. A piano hammer forming machine including a press provided with a plurality of horizontally moving clamping blocks, and a pair of vertically moving power rods, means carried by the power rods for removably receiving the base of a piano hammer head strip, a die arranged beneath said piano hammer head strip, said die being adapted to receive an outer felt to be applied to said base, said power rods acting to move said base so as to compress to a desired extent the central part of said outer felt, a pair of dies positioned so that onedie will be on each side of said outer felt, one of said pair of dies being hollow, said dies being slidable whereby when said clamping blocks are moved toward each other said dies will be moved toward each other accordingly and will fold and press said outer felt against said base, and means for locking said dies in their clamping position, said dies being bodily removable while in their clamping position whereby when said base is released the piano hammerhead strip and dies may be moved to one side until the felt has properly set, said means for locking said dies including a pair of sliding cams continually projecting into said hollow die, each of said cams having a turned-up portion within said hollow die and a spring for each cam positioned be tween one wall of said hollow die. and the respective turned-up portions for giving the cams a continuous tendency to move against the hollow die for locking the die against a return movement.

7 In a piano hammer forming machine a pair of dies, a guide bar extending from one of said dies, said bar slidingly extending through the other die, said other die being hollow, a cam associated with each of said guide bars for looking the dies against separation after having been moved to a clamping position, said cams extending into said hollow die, a spring acting on each of said cams and on one wall of said hollow die for giving the cam a continuous tendency to move toward the hollow die whereby the hollow die is locked against a return movement, means for holding the base of a piano hammer strip so that said dies may press the outer felt against the same, and power means for moving said dies to a clamping position, said dies with the strip clamped thereby being bodily I removable from the supporting and clamping means while in a clamping position, whereby said supporting and clamping means may be used for a second operation immediately after the dies have been moved to a clamping posigo tion.

WILLIAM J. PFRIEMER.

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