US1256252A - Bed-reciprocating mechanism. - Google Patents

Description

H. PEARCE & F. SPENCE. BED RECIPROCATING MECHANISM.

APPLICATION FILED MAY 6. I916.

Patented Feb.12,1918.

4 SHEETS-SHEET I FIGJ.

FI iI 1 H. PEARCE & F. SPENCE.

BED RECIPROCATING MECHANISM.

APPLICATION FILED MAY e. 1916.

.1 ,256,2 52. Patented Feb. 12,1918.

4 SHEETS-SHEET 2- H. PEARCE & F. SPENCE.

BED RECIPHOCATING MECHANISM.

APPLICATIOI! FILED MAY 6, I916.

Patented Feb. 12, 1918.

4 SHEETS-SHEET 3.

H. PEARCE & F. SPENCE.

BED RECIPHOCATING MECHANISM.

APPLICATION FILED MAY 6. 1916.

1,256,252. v Patented Feb. 12, 1918.

4 SHEETS-SHEET 4- nrrn TAT-ES ra rnnr ore-ion.

HERBERT PEARCE AND FRED SPENCE, 0F BROADHEATH, ENGLAND, ASSIGNORS TO LINOTYPE AND MACHINERY LIMITED, OF LONDON, ENGLAND.

BED-RECIPROCATING MECHANISM.

Specification of Letters Patent.

Patented Feb. 12, 1918.

Application filed May 6, 1916. Serial No. 95,767.

To all whom it may concern:

Be it known that we, HERBERT PEARCE and FRED SPENCE, subjects of the King of the United Kingdom of Great Britain and Ireland, and residing at Linotype and Machincry Works, Broadheath, in the county of Chester, England, have invented new and useful Improvements in Bed Reciprocating Mechanism, of which the following is a specification.

This invention relates to mechanism for reciprocating parts of machines such as the beds of flat bed printing presses, and, as it is especially applicable for use in connection with those beds, the following description is restricted to that application, although it is to be understood that the invention may equally well be employed in connection with the reciprocation of the beds of planing and similar machines.

More particularly, the invention may be said to relate to that class of mechanism in which the control of the bed is transferred near each end of its travel to and from a respectively different crank pin which effects the slowing down, stopping, reversing and acceleration of the bed and from which the said control is transferred to the normal bed-operating gear which operates the bed at uniform velocity during the actual printing stroke and the return stroke.

To secure the best results in a flat bed printing press, it is necessary that the bed travel through its printing and return strokes at a uniform velocity and that, at the end of these strokes, and with as little strain as possible, the bed be brought gradually to a stop and have its direction of travel reversed and its velocity in the reverse direction gradually accelerated from the stop or zero up to the maximum. It is also of very great importance that for the slowing down, stopping and reversal of the bed, as small a proportion as possible of the beds total travel be utilized, because the smaller that proportion, the greater will be the proportion available for printing, and consequently the greater will be the length (measured in the direction of the beds travel) of the surface which can be printed at each cycle of the press.

In presses having reciprocating mechanism of the above-named class it has heretofore been proposed to employ a reversing device comprising a single crank pin to which.

are pivoted the meeting ends of two connecting rods whose outer or opposite ends are pivotally connected each to a slide rectilinearly reciprocated by the crank pin ina direction parallel with the movement of the bed, and devices including a single automatically operated latch for connecting the bed to, and disconnecting it from, the said slides in alternation near respectively opposite ends of the beds travel, the arrangement being such that the control of the bed is transferred from the normal bed-operating gear which operates the bed at uniform velocity during the actual printing stroke and the return stroke, to the crank pin, and again from the crank-pin to the normal bed-operating gear, at opposite ends of the travel of the bed, each complete reversal being; effected while the bed is under the control of the crank-pin and within a period which is less than one half of that occupied by one rotation of the crank, the travel of the bed at uniform velocity being thereby extended beyond the period occupied by one complete rotation of the bedd1;'iving pinion.

The object of the present invention is to secure a result similar to that just referred to, so far as regards the period within which each complete reversal is effected, and to extend the travel of the bed at uniform velocity beyond the period occupied by one or more complete rotations of the bed driving pinion, by employing two crank pins, each operating its own connecting rod and slide and each effecting the reversal at only one end of the travel of the bed, instead of relying, as in the before mentioned arrangement, upon a single crank pin, or, as in another known arrangement, upon a single reciprocating member under the constant control of two crank pins, to effect the reversal at both ends of the travel of the bed.

The invention will now be described by reference to the accompanying drawings, in which it is illustrated as applied to a machine of similar construction to that dealt with in the original application, and in which Figures 1 and 1 together form a side elevation of part of the said machine,

Fig. :2 is an end elevation of part of the same, and

Figs. 3, st, 5 and 6 are diagrammatic side elevations of certain organs of the bed-operating lllQClltllllSIIldll. the different positions respectively assumed by them at four difi'erent stages of their cycle of operation.

Referring first to Figs. 1, 1 and 2, 1 is the bed motion shaft which is rotatable in suitable bearings, only one of which, viz., that marked 2 is represented, see Fig. 2. The bearing 2 has fast to it an extension or sleeve 3 on which is mounted the bed pinion 4 with a capacity of moving both rotatably and axially thereon. The pinion 4 is main tained in constant driving connection with the shaft 1, whatever be the position of the former upon the sleeve 3, by the well-known arrangement of a crank 5, rigidly secured to the inner end of that shaft and engaging with a groove or recess 6 formed in or on the said gear wheel, as shown in dotted lines in Figs. 1 and 2.

The bed motion shaft- 1, has rigidly secured thereon a spur pinion 7, which, through an intermediate wheel 8, drives a gear wheel 9 fast on a countershaft 10 through which, as hereinafter described, the return or non-printing stroke of the bed 11 is effected.

The bed pinion 1 is capable of being moved axially along the sleeve 3 into two different positions in one of which, viz., that in which it is shown in Fig. 2, it is in engagement with the bed rack 12 which is fast to the underside of the bed 11, and in the other of which it is at the left-hand side, as viewed in Fig. 2, and out of the path of the said bed rack; in this last-named position the upper portion of the bed pinion 1 is located, and free to rotate, in a recess 13, indicated in dotted lines in Fig. 2, in the adjacent part 14 of the press frame, this part 14, like those marked respectively 15, 16, presenting at its upper surface, as ordinarily, a track for the rollers 48 which support the bed 11 throughout its longitudinal travel.

The rack 12, being that which propels the bed 11 throughout the part of its printing stroke which is of uniform velocity, is situated as nearly as possible at the center of the width of the said bed. so as to minimize any tendency of the bed to twist under the strain exerted on it by the bed pinion The before-mentioned countershaft 10 has fast on it a spur wheel 17 which is in con stant driving connection with a bed pinion 18 rotatably and axially movable on a sleeve 19, axially alin-cd with, but independent of the bed motion shaft 1. The bed pinion 18, which is of the same diameter as the bed pinion 4, by its axial movement on the stud 19, is capable of being moved into and out of engagement with the bed rack 20, which, l ke the before-described bed rack 12, is fast to the underside of the bed 11. WVhen the bed pinion 18 is out of engagement with the bed rack 20 (which is the condition in which it is shown in Fig. 2) the upper part of it is received, and free to rotate, in a recess 21, indicated in dotted lines in Fig. 2.

B y the before-described apparatus the two the bed 11 is traversed in relatively opposite directions. Fig.2 represents the bed pinion (-L enmeshed with the bed rack 12 and the bed pinion 18 disengaged from its bed rack the printing stroke of the bed 11 during the return or non-printing stroke of the bed 11, the bed pinion 4 is out of engagement with its bed rack 12, and the bed pinion 18 is in engagement with its bed rack 20. As the amount of resistance to the travel of the bed 11 during its return or non-printing stroke is less than that to be overcome during the printing stroke, the bed pinion 18 and bed rack 20 can, as shown in Fig. 2, be of lighter construction or less width than that of the pinion 4 and rack 12.

The bed pinions 1 and 18 receive their axial movement through the following means. such pinion there is provided an annular groove 22 with which are engaged two gibs 23 carried by the upper arms of a bifurcated lever 24 adapted to be rocked about a stationary pivot 25, by a grooved cam 26 or 27, rigidly secured to a cam shaft 28 to which continuous rotary motion is imparted by any suitable gearing. The cams 2G, 27, operate the levers 24 through rollers on the lower arms of the latter engaging with the grooves of the former, and the said cams are so constructed that the bed pinions 4c, 18, are moved alternately into and out of operative alinement with their respective bed racks 12, 20, during the periods occupied by the slowing down, stopping, reversing and accelerating of the beds motion, the pinion so moved out of engagement being maintained in that condition throughout each such period. So far as this cam mechanism is concerned, the arrangement just described is or may be substantially the equivalent of that heretofore used for a like purpose, the only material difference being that the cams 26, 27, are arranged to maintain the bed pinions 1-, 18, in gear each with its respective rack 12, 20, throughout a rotary motion of rather more than 360 degrees, say 360+2a degrees.

To the inner end of the bed motion shaft 1 there is rigidly secured a plate 29 with which is integral, or to which is rigidly attached, the crank pin 30 on which is pivoted one end of a connecting rod 32.

The before mentioned sleeve 19 is fast to a bearing 2 in which rotates a shaft 1, axially alined with but independent of the bed motion shaft 1. The shaft 1 is pro- 20, which is the condition obtaining during In the exterior of the boss of each vided with a spur wheel 51 in mesh with the wheel 17 fast to the countershaft 10. The pinion 18 is maintained in constant driving connection with the shaft 1, whatever be the axial position of the former upon the sleeve 19, by a crank 5 secured to the inner end of that shaft and engaging with a groove 6 formed in or on the pinion, the arrangement in this respect being a replica of that hereinbefore described in connection with the pinion 4.

According to the present invention the function of the crank pin 30 is restricted to the operation of the connecting rod or link 32 and slide 36 connected to that red by pin 34 and reciprocating in the horizontal guides 37, and the connecting rod 31 and slide 35 pivoted thereto by pin 33, are controlled by a second crank pin 30 provided in connection with the pinion 18. In the constructional form illustrated, the shaft 1, for this purpose, has rigidly secured to it a plate 29 with which is integral, or to which is rigidly attached, the crank pin 30, whereon one end of the rod 31 is pivoted. The slide 35 operated by the last-mentioned rod and the additional stationary horizontal guides 37 provided to receive it, are arranged so that the hook A, A of that slide will be presented toward the side of the hanger 38 opposite theside toward which the hook B, B of the slide 36 is presented. The two cranks are so disposed angularly with reference to each other that during their rotation in opposite directions they both reach the dead center on the same side of the respective shaft at the same instant; in other words, in the case of the constructional form herein dealt with, wherein the crank shafts 1 and 1 are co-axial, the cranks would be set diametrically opposite to each other on the vertical line passing through their common axis of rotation.

The hanger 38 is preferably located midway between the two cranks 29, 29 and is provided on each side with an independent reversing stud 39 or 39 and cam-operated latch 40 or 40. Each latch is a replica of the other, and cooperates respectively with a cam track 42 or 43 and a slide 35 or 36 for reversing the bed at one end of its travel. The latch 40 is provided with an upstanding arm carrying an anti-frictiou roller 41, which engages with a cam race 43, see Figs. 1 and 2, at or near the respective end of the beds travel so as, at the required times, to move the latch into and out of engagement with the hook B. At the times at which the latch is not acted upon by the cam race 43, it is supported in its higher position by a spring 44, Figs. 1 and 2, attached, at one end, to the hanger 38 and, at the other end, to an arm 45 extending downwardly from the boss of the latch 40. The movement of the latch 40 under the action of the spring 44 is limited by a pin or stop 46 fast to the hanger 38, this stop being so positioned that the latch is maintained at the level of the higher portions of the cam race 43, at all such times as the roller 41 is not engaged with that cam race; by this arrangement of spring 44 and stop 46, the roller 41 is maintained in proper position to enter the cam race 43 as the bed 11 approaches the termi nation of the respective stroke.

To prevent any damage being caused by reason of the latch 40 being deprived of the support given to it by the spring 44 (say by breakage of the latter), the hanger 38 has rigidly fixed thereto a stop 49 which underlies the said latch and would, in the event of such breakage, support the latch during its travel, in such a position as would enable the roller 41 thereon to travel up a ramp 50 provided on the inner end of the cam race 43, this ramp serving to guide the said roller into the higher portion of the said cam races.

The just recited description of the latch 40 and of the parts appertaining thereto and cooperating therewith is equally applicable to the latch 40 and the parts appertaining to and cooperating with that latch, these latter parts being respectively identified by the same numerals as those given to the parts pertainin to the latch 40, but with an added superior a in each case; for this reason no further description of the construction is herein deemed to be necessary.

The operation of the mechanism may be described as follows, assuming, as a convenient stage from which to start such description, that the bed 11 is just commencing its printing stroke. At that instant the position of the parts is as indicated in Figs. 1, 1 and 2 and, diagrammatically, in Fig. 3. The bed 11 and slide 36 are then traveling in the same direction at the same speed, and the pinion 4 has just run into mesh with the rack 12, having been previously brought into the path of that rack by the action of the cam 26. Immediately thereafter the latch 40 is moved about its pivot 47 out of engagement with the hook B, B on the slide 36 by the action of the cam race 43 on the roller 41, and the stud 39 also moves out of contact with the said hook by reason of the now slower movement of the latter, and the bed 11 continues its printing stroke under the sole control of the pinion 4 and rack 12, the latch 40, when it has run beyond the control of the cam race 43, being meanwhile maintained in its raised position against the stop 46 by the spring 44 acting on the arm 45. Fig. 4 represents diagrammatically the relative positions of certain of the parts when the bed has completed one half of its printing stroke.

as the bed 11 approaches the end of its printing stroke, that is to say, at or about the instant at which the pinion 4 completes the next 360-l-2a degrees of angular motion (a being the angle defined in the original application and hereinafter more particularly referred to) from the position indicated in Figs. 1 and 3, the bed rack 12 runs out of mesh with the pinion 1, and the slide 35 is traveling at the same velocity as the bed. At or about that instant the reversing stud 39 abuts against the hook-member A on the slide 35 and the roller 11 of the latch 40 which had by that time already been depressed by passing along the descending portion of the cam race 12, completes the engagement of that latch with the hook A, A thus, for the time being, locking the bed 11 to, and placing it under the control of the crank pin 30 This is the condition diagrammatically represented in Fig. 5. The slowing down, stopping, reversing and speed ing up of the bed now take place during the next ensuing angular motion of say 180 2a degrees of the crank pin 30 that is to say, the movement of the crank pin to the position in which it is represented in Fig. 6, just as though the said crank pin were in permanent operative connection with that bed, and at any part of the time occupied by the just-- named angular movement of the crank pin, the cams 27, 26 effect a lateral movement of the bed pinions 18 and 4, to bring the former (18) into a position in which it will subsequently be engaged by the rack 20 during the next ensuing or already started non-printing stroke, and the latter (4) out of the path which will be pursued by the rack 12 during thatstroke. At the completion of the just mentioned angular motion of 1802a degrees of the crank pin 30, the hook A, A is again traveling at the same velocity as is the bed 11. At that juncture the bed rack 20 runs into mesh with and is operatively engaged by the pinion 18, and the mutual separation of the stud 39 hook A, A and latch 40 commences, the latch being raised clear of the hook A, A by the ascending part of the cam race 12, in the same manner as the latch to was previously raised by the cam race 43 at the commencement of the printing stroke. 1

The bed 11 is then traversed through its non-printing stroke at uniform velocity by the rack 20 and pinion 18, and at or about the instant at which the pinion 18 completes say 360+2a degrees of angular motion from the position at which the bed started the portion of its non-printing stroke of uniform velocity, the bed rack 20 runs out of mesh with the pinion 1S and the hook B, B is traveling at the same velocity as the bed, and at or about that instant the reversing stud 39 abuts against the. vertical member'B of that hook, and the roller 41 (which, by that time, had already been depressed by passing along the deflected part of the cam race -13) completes the engagement of the latch 40 mamas with the hook 13, thus, again, placing the bed 11 under the control of the crank pin 30. The slowing down, stopping, starting on the printing stroke, and speeding up of the bed 11 now take place during the next say 1802a degrees of angular motion of the crank pin 30, and at any part of the time occupied by this angular movement of the crank pin, the cams 26, 27, eifect a lateral movement of the bed pinions l and 18, to bring the former 1) into a position in which it will subsequently be engaged by the rack 12 during the next ensuing or already started printing stroke, and the latter (18) .out of the path which will be pursued by the rack 20 during that stroke. At the conclusion of the just-mentioned 180-2a degrees angular motion of the crank pin 30, the respective organs are once again in the positions indicated in Figs. 1, 1 2 and 3, and the justdescribed cycle of operations is thereafter repeated. The directions of travel of the 'arious parts at the particular stages represented are respectively indicated by the arrows on Figs. 3, 4, 5 and 6.

To insure satisfactory engagement between the bed and reversing slide, such engagement must necessarily be effected at an instant at which the slide is moving in the same direction as the bed and at the same or approximately the same velocity. This condition can best be obtained, when the slide is reciprocated by a-crank moving with the same angular velocity as the bed driving pinion, by so proportioning the lengths of the connecting rod and crank that the equation L =7, cos a sin b is satisfied, where L represents the length of the connecting rod, 7" the radius of crank arm, a and Z) the angles formed by the crank radius and connecting rod respectively with the vertical and horizontal lines passing through the axis of rotation of the crank, at the instant at which the engagement between the bed and slide takes place, tan I) having a value B being the radius of pitch line of bed driving pinion and w the horizontal distance between the reciprocating end of the connecting rod and the axis of rotation of the crank at the same instant, whether or not the said distance w be equal to one half the travel of the bed at uniform velocity. The present invention, as will be readily understood, could easily be applied to an arrangement in which the travel of the bed at uniform velocity would extend over a period occupied by two or more complete r0.- tations of the bed driving pinion, irrespective of the increase over and above such period secured by the employment of the improved reversing mechanism. Consequently, it is to be understood that although the invention is herein illustrated in a constructional form in which the distance as is equal to half the travel of the bed at uniform ve locity, and in which such travel would, without the increase secured by the improved reversing mechanism, extend over a period occupied by only one complete rotation of the bed driving pinion, it is not limited to any such arrangement, and that the details may be considerably varied without any doparture from its essential features.

Having described our invention, we declare that what we claim and desire to secure by Letters Patent is 1- In bed reciprocating mechanism, the combination with a reciprocating bed and means adapted to rectilinear-1y reciprocate it at uniform velocity, of two rectilinearly guided slides, two cranks rotating in relatively opposite directions and so disposed angularly with reference to each other that they both reach the dead center on the same side of the respective axis of rotation at the same instant, two connecting rods respectively connecting the said slides and cranks whereby the slides are reciprocated at velocities varying downwardly to and upwardly from zero, a hook fast to each slide, a stud rigid with the bed and adapted, near respectively opposite ends of the beds travel, to engage with and disengage from the hooks in alternation, a latch pivotally connected to the bed and accompanying it throughout its travel, and means adapted to automatically effect the engagement of the latch with and its disengagcn'ient from the said hooks in alternation, the respective engagements and disengagements being effected at instants at which the velocity of the respective slide is equal or approximately equal to that of the bed and within a period which is less than one half of that occupied by one rotation of the respective crank.

In witness whereof the said HERBERT PEARCE has set his hand in the presence of two witnesses.

HERBERT PEARCE. l/Vitnesses:

HENRY CARTER PUGH, HAROLD SoU'rHwoR'rH. In witness whereof the said FRED SPENCE has set his hand in the presence of two witnesses.

FRED SPENCE.

\Vitnesses:

WARWICK HENRY WILLLAMs, HENRY WHEELER.

Copies of this patent may be obtained for five cents each. by addressing the Commissioner of Patents,

Washington, D. C.

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