US788931A - Cushioning mechanism for reciprocating beds. - Google Patents

Description

No. 788,931. PATENTED MAY 2, 1905.

' G. A. MCCAIN. GUSHIONING MECHANISM FOR REGIPROGATING BEDS.

APPLIGATION FILED MAY 21, 1904.

2 SHEETS-SHEET 1.

w L Z) MM PATENTED MAY 2, 1905.

G. A. MCCAIN. GUSHIONING MECHANISM FOR RECIPROOATING BEDS.

APPLIGATIONFILED MAY 21, 1904.

2 SEBETS-SHEET 2.

PATENT Patented May 2, 1905.

Tries.

CYRUS A. MCCAIN, OF CHICAGO, ILLINOIS.

CUSHIONING MECHANISM FOR RECIPROCATING BEDS.

SPECIFICATION forming part of Letters Patent N 0. 788,931, dated May 2, 1905.

Application filed May 21, 1904:. Serial No. 209,049.

To all w/eom it may concern:

Be it known that I, CYRUs A. MCCAIN, acitizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Cushioning Mechanism for Reciprocating Beds, of which the following is a specification.

My invention relates to improvements in aircushions for the reciprocating beds of printing-presses, planing-machines, and the like.

My object is to provide certain improvements in the construction of air-cushioning devices or attachments for the purpose stated whereby the cushioning action against the bed may be regulated with great accuracy to produce the most desirable results under all conditions.

In the drawings, Figure 1 is a broken view showinga longitudinal section of my improved cushioning mechanism particularly adapted for printing-presses; Figs. 2 and 3, sections taken on lines 2 and 3 in Fig. 1 and viewed as indicated by the arrows; Fig. 4, a longitudinal section of a printing-press with my improvements applied thereto, and Fig. 5 a broken plan view of one side portion of the press.

The frame of the printing-press has end bars A, to which the air-cushioning cylinders B are attached, each cylinder having a closed end (0, provided with a central threaded opening 6 to receive a supporting-bolt c. In each cylinder is a stationary diaphragm C, separating the cylinder into chambers D E. The diaphragm is provided with a central port or opening (Z, surrounded by a valve-seat e in the chamber E, and is also provided with one or more ports or openings f, fitted in the chamber D with preferably flap-valves g, of leather, rubber, or the like flexible material. The bolt 0 is in line with and extends nearly to the opening d and forms a support and guide for a valve 7t, closing normally against the seat a. Surrounding the opening Z) at the inner side of the end wall a is a flat guide-surface i, and sliding upon the bolt 0 in ra] spring 20.

F is a loop-shaped wedge through which the bolt 0 passes and which is pivotally connected to the end of a stem G, which passes through a stuffing-box q in the cylinder. The wedge has a flat face which slides against the surface 2 and an inclined face sliding against the surface m of the follower. Upward or inward movement of the wedge to the position indicated in Fig. 1 moves the follower in the direction away from the surface 6 to compress the spring 7), while reverse movement of the wedge until it is stopped by the lip 01. permits the spring 72 to expand to decrease its tension against the valve it. Extending through the cylinder-wall to the chamber E is a port r, surrounded at its outer side with a seat for a puppet-valve s. The valve 8 is upon a stem 13, passing through the port 9' and carrying within the chamber E a head 0), confined between which and the shell is a spi- The stem tis threaded and provided at the outer side of the valve s with a nut as, turning of which increases or decreases the tension of the spring to.

Working in the chamber Dis a piston Hon a stem I. The piston has openings through it, y, fitted with flap-valves e at the inner side.

In practice the stem 1 would be connected to move with the bed K of the printing-press, and the stern G may be connected with any usual governor mechanism. As the bed of the press nears the limit of its movement in one direction the piston H is moved in the direction of the diaphragm C to compress the air in the chamber D. When the air thus compressed exceeds the resistance of the spring 3), the valve h is opened to permit the pressure to pass into the chamber E, and when the pressure in the latter chamber against the valve 8 exceeds the resistance of the spring to the said valve is opened to permit the pressure to vent.

It is desirable to so regulate the cushioning effect of the air in the chamber D against the piston that the resistance will increase with any increase in speed of the press and diminish as the speed of the press becomes less. The strength of the air-cushion is-determined by the resistance of the spring 3) and of the supplemental air-cushion formed by the chamber E. To change the resistance of the spring 7), the wedge F is adjusted, and to facilitate this i position it may have a resistance of, say, sixty adjustment I prefer to mark the rod or stem with a scale 4:, as indicated. I also provide upon the stem 2? of the valve .9 a scale 5, registering with a pointer or the like 6, carried by the nut w, whereby the tension of the spring may be indicated. By these means the aircushion may be nicely adjusted for any resistance desired. In the movement of the bed K of the press in the direction before stated the air in the chamber D when compressed to overcome the resistance of the valve 72 passes into the chamber E, filling the latter with pressure to the point of overcoming the resistance of the spring on, and the cushion may thus be regulated by the adjusting means described, so that the piston will slow up and stop before reaching the diaphragm C. In

the return stroke of the piston the air compressed in the chamber E will open the flapvalves 9 and supplement the pressure in the chamber D in aiding the initial movement of the bed on its return stroke. When the rod G is operatively connected with a speed-governor on the press, the wedge F will be moved inward as the speed of the press increases and outward as the said speed diminishes, thereby increasing or decreasing the resilient force of the air-cushion, as required.

I provide one or more air-cushions of the improved construction described at each end of the bed K.

Hitherto in cushioning devices of this kind it has been usual to cause the piston to work against an air-cushion the resistance of which is greatest at the end of the stroke of the pis' ton and when the bed is at the end of its slowlng-up motion. Thus the bed-operating mechanism meets with the greatest resistance at given motion as the piston nears the end of its compression-stroke to reduce the cushioning resistance as the bed slows up and its operating mechanism crosses the dead-center.

Presuming, for example, that a pressure of sixty pounds to the square inch is the maximum desired against the piston forcushioning the bed under normal speed thereof, the wedge F may be adjusted with relation to the press-speedgoverning mechanism to cause the spring 1 to exert, say, fifty pounds closing pressure against the valve h when the press runs at normal speed and the valve 8 may be adjusted to have a resistance of, say, ten pounds. When the wedge is at its lowermost position, the spring p may have a resistance of, say, ten pounds and when at its highest pounds, and as the press speeds up the closhas moved, say, slightly beyond three-quarpounds. Thus in practice when the press first starts to run the resistance of the valve It would be not over approximately twenty ing pressure against the valve h would be increased by the rising of the wedge, which operates as a governing means for said valve, so that when the speed of the press is at normal the maximum resistance against the piston would not exceed sixty pounds to the square inch. The parts may be so regulated. with relation to each other that the maximum pressure would be reached when the piston 8c ters the length of the chamber D. In the movement of the piston through the last quarter of the chamber the pressure would remain at sixty pounds, provided the wedge or valve-governor F remains in one position. However, if, as before stated, the connection between the said wedge and the press-speedgoverning mechanism is such as to cause gradual lowering of the wedge during the said final travel of the piston then the cushioning resistance against the piston will gradually reduce. There is adecided advantage in thus reducing the cushioning resistanceduring the slowing up of the bed, so that comparatively little resistance is presented to the piston as the press-operating mechanism is crossing its dead-center. The ten pounds of atmospheric pressure in the chamber E at the end of the compressing stroke of the piston will aid in starting the piston on its return stroke.

In Figs. 4 and 5 I show for purposes of illustration a desirable form of mechanism for operating the wedges F of the cushioning devices, whereby the cushioning resistance against the pistons may be regulated as desired to reach the maximum before the pistons arrive at the ends of their compressionstrokes and operating automatically to gradually decrease the cushioning resistance as the pistons move to the ends of their compressionstrokes. It is to be understood that the mechanism'illustrated for operating the wedges F is designed more especially for use in the particular type of printing-press shown. The mechanism is not claimed in the present application, and my invention is not to be limited to this particular construction of mechanical means for moving the wedges.

In the press shown, Y is the main driveshaft, and M is a cam-shaft rotating at the same speed as the impression-cylinder N. On the cam-shaft is a cam M. Fulcrumed upon a bracket Pin the frame is a horizontallyswinging bell-crank lever P, having the camengaging arm 6 and the arm 7.

8 is a longitudinally-movable rod having fixed thereto an arm 9.

10 is a double toggle, pivotally connected at one toggle-joint to the end of the arm 9 and pivotally connected at its opposite joint to the end of the arm 7 of the bell crank lever. The other opposite joints of the toggle are pivotally connected to thrust-rods 11.

12 12 are rock-shafts journaled in brackets 13 on the end portions of the frame. Fastened to the rock-shafts 12 are downwardlyextending fingers 14, pivotally connected to the ends of the rods 11. Also on the rockshafts are bifurcated fingers 15, which loosely D embrace the stems G between adjustable nuts or collars 16 on the stem. On one side of the machine is a plate 17, having a scale marked thereon, as shown. Journaled in the plate is a shaft carrying a pointer 18 and a pinion 19. 5 This pinion meshes with a pinion 20 on a shaft which carries a finger 21, pivotally engaging the end of the rod 8. The parts may be so constructed that when the indicator or pointer 18 registers with the figure 10 on the scale 3 the double toggle will flex to the extent inclicated. Movementofthepointeralongthescale causes the rod 8 to be thrustin the downward direction in Fig. 5 to extend the toggle by moving the arm 9 nearer to the end of the 5 arm 7. When the parts are in the position shown, for example, in Figs. 4 and 5, the double toggle will cause the rods L to position the rock-shaft 12 and hold the stems G in a low position, whereby the wedges F are in v the lowest position of practical adjustment and the springs p are tensioned to present ten pounds resistance against the opening of the valves h. This is the preferred position of the parts when the press is first started. The sscam M is formed with an abrupt cam-groove, as indicated in Fig. 5. In the movement of the bed K in either direction this abrupt portion of the cam engages the finger 6 at the time when the pistons have traveled, say, 9 three-quarters of the distance into the cylinders. The further rotation of the cam-shaft swings the bell-crank lever and moves the toggle to draw upon the rod extending in the direction of the cylinders where the cushion- 5 ing is taking place and rocks the respective shaft 12 to lower the wedges F and reduce the resistance of the cushioning-springs p. Thus in the travel of the pistons to the ends of their strokes the cushioning resistance is decreased. When the press is first started, the only cushioning resistance at the time that the driving mechanism is crossing its deadcenter may thus be that of the compressed air in the chambers E. As the press speeds 5 up the pointer 12 will be turned by the operator as far as desiredsay to the position of maximum cushioning marked on the scale 17. This turning of the pointer thrusts the rod 8 to carry the arm 9 more or less 0 nearly to the vertical plane of the rods 11, whereby the toggle is extended more or less nearly to its fullest extent to raise the wedges F. When in this latter position, the wedges will remain in the raised positions, as indi- 5 cated in Fig. 1, until the pistons have moved in the cylinders to within, say, one-fourth of the length of the chamber D from the partitions 0, when the cam M will swing the bell-crank lever to lower the wedges at that end and gradually decrease the resistance of the springs 9 until the pistons reach the ends of their compression-strokes.

The valve .9 offers a means for testing the amount of pressure that passes through the valve h at different speeds of the bed, so that at any time it may be determined without the use of a pressure-gage whether or not the valves and piston are working properly.

While I prefer to construct my improvements throughout as shown and described, they may be variously modified as to details of construction without departing from the spirit of my invention as defined by the claims.

What I claim as new, and desire to secure by Letters Patent, is-

1. In an air-cushion device of the character described, the combination with the piston, and piston-chamber having a vent-opening, of a valve for said opening, valve-governing mechanism operating to bring about the maximum cushioning resistance before the piston reaches the end of its compressing stroke, and actuating means for said mechanism operatively connected with the bed-reciprocating mechanism and moved thereby to gradually decrease the said resistance as the piston moves to the end of its compressing stroke.

2. In an air-cushion device of the character described, the combination with the piston, and piston-chamber having a vent-opening, of a valve for said opening, a spring exerting closing pressure against the said valve, spring tensioning mechanism operating to bring about the maximum cushioning resistance before the piston reaches the end of its compressing stroke, and movable to gradually decrease said resistance as the piston moves to the end of its compressing stroke, a supplemental cushioning chamber through which the air discharged from the piston-chamber passes, an air-escape retarding-vent for the supplemental chamber, and a valved passage between the supplemental and piston chambers through which pressure retrogresses to bear against the piston at the beginning of its return stroke, substantially as set forth.

3. In a cushioning device of the character described, the combination of a cylinder having a main cushioning-chamber and a close supplemental cushioning-chamber,an air-compressing piston in the main chamber, a diaphragm between the chambers having an opening through it, a valve for said opening in the supplemental chamber, means for regulating the resistance of said valve against opening under the compressing stroke of the piston and means for opening communication between the chambers in the return stroke of the piston, substantially as and for the purpose set forth.

4:. In a cushioning device of the character described, the combination of a cylinder having a main cushioning-chamber, and a close supplemental cu shioning-chamber, an air-compressing piston in the main chamber, a diaphragm between the chambers having an opening through it, a valve for said opening in the supplemental chamber, means for regulating the resistance of said valve against opening under the compressing stroke of the piston, means for opening communication between the chambers in the return stroke of the piston, and a vent-valve for the supplemental chamber, substantially as and for the purpose set forth.

5. In a cushioning device of the character described, the combination of a cylinder having a main cushioning-chamber and a close supplemental cushioning-chamber, an air-compressing piston in the main chamber, a diaphragm between the chambers having an opening through it, a valve for said opening in the supplemental chamber, means for regulating the resistance of said valve against opening under the compressing stroke of the piston, means for opening communication between the chambers in the return stroke of the piston, and a vent-valve for the supplemental chamber having means for regulating its resistance adjustable from the outside of the cylinder, substantially as and for the purpose set forth.

6. In a cushioning device of the character described, the combination of a cylinder having a main cushioning-chamber and a. close supplemental cushioning-chamber,an air-cornpressing piston in the main chamber, a diaphragm between the chambers having an opening through it, a spring-pressed valve for said opening in the supplemental chamber, means for regulating the resistance of said spring and means for opening communication between said chambers in the return stroke of the piston, substantially as and for the purpose set forth.

7. In a cushioning device of the character described, the combination of a cylinder having a main cushioning-chamber and a close supplemental cushioning-chamber,an air-compressing piston in the main chamber, a diaphragm between the chambers having anopening through it, a spring-pressed valve for said opening in the supplemental chamber, means for regulating the resistance of said spring comprisinga wedge in the supplemental chamber against which the spring bears adjustable from the outside of the cylinder, and means for opening communication between said chambers in the return stroke of the piston,

substantially as and for the purpose set forth. 6

CYRUS A. MCCAIN.

In presence of WALTER N. WINBERG, W. B. DAVIES.

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