US1547828A - Automatic clamping device for paper-cutting and other machines - Google Patents

Description

July z8, 1925. 1,547,828

J,.F. SGHROETER AUTOMATIC CLAMP'ING DEVICE FOR PAPER'CUTTING AND OTHER MACHINES Filedqvxay 2 8, 1923 4 sheets-'sheet 1 l 4 ATTORNEY July 28, 1925. V1,547,828

J. F. SCHROETER AUTOMATIC SLAMPING DEVICE FOR PAPER CUTTING AND'OTHER MACHINES Filed may 28. 1923 4 sheets-sheet 2 INVENTQB l E56/mom `ATT0RNEY July 28Il 1925. A E 1,547,828 J. F. SCHROEITER` lmTonuvlIc cLmPIuG DEvTcE EOE PAPER CUTTING AND OTHER uAcHINEs Filed May 2. laas 4 sheets-sheet gs. u w l n E g lo 7 o, I A\\\\\\\\\\\\\\ n f {ll/ l@ m A TTOR Mx/A )..mmmll//f f 5 E y Q fr w l IRSC/2me@- July z8, 1925. 1,547,828

J. F. SCHROETER AUTOMATIC CLAMPING DEVICE FOR PAPER CUTTING AND OTHER MACHINES Filed May 28. 192s 4 sheets-sheet 4 q. 7 l V.'L'q al 3 i3 3 34 I 31. 35 34 0 /l 32 A 1N VEN TOR .l

A TTORNEY Patented July 28, 1925.

.THN iwscnnon'r'nn.- 0F ATLANTA, GEORGIA.

AtoivIA'iI'o CLAMPING D'Evon non PAPER-CUTTING AND OTHER MACHINES.

Appncatian ined May' 2t, 1923. 'sensi Nt. 641,881.

To a'ZZ whom t may conceda:

Be it known that I, JoiiN F. SoiiiO'TEiz, a citizen of the United States, and a resident of the city of Atlanta,

State of Geoigia have invented a new 'and useful Improvement in Automatic Clamp# ing Devices for Papei-Cutting and Other Machines,of which the following is a specincation. i

The object of my invention is to provide machine of this class, or any similar class, wherein' a clamp' is employed for holding material on a table or other support either manually or automatically or both, and which will be simple in construction', easily assembled or taken do'uin` and whichv4 will be reliable in operation; This and other ob'- jects are accomplished hy my invention, one embodiment of which is hereinafter more particularly Vsst forth. z

For a more particular description of my invention, reference is to hev had to the accompanying drawings-forming a part hereof, in `Which Figure l is a rear section of a paper cutter provided with my improvedI clamping mechanism, part'being vsectionally taken on the line l-1 of Figure 2, looking in the direction' of the arrows. I Figure 2 i's a sectional view taken o-n the, line of Figure l, looking in the direc'- tion of the arrows.

Figure 3 is a reduced' sectional view with parts omitted which shows the clamp in operation.

Figure 4; is a longitudinal sectional view of a portion of a pitinan, a ratelnt4 and spiral ,gear and connecting' parts being shown'. f

Figure 5 is e 'sectional view taken on the line .fi-+5 of Figure 4, looking in the direction of the arrows.

Figure 6 is a sectional vieiv taken on the line 6-6 of Figure 7, looking in the direc'` tion of the ariows.

' Figures 7 and 8 showt7 the "itman and connected parts, the tivo views eing tal'en at right angles to each other and parts being 'shown in section. y

Figure 9 shows a second form of ratchet 'corresponding to the ratchet shov'vn in Fig# ures 4 and 5, and Figure l0 'shows a modii fied structure.

county of Fulton, and

lThro-uhout the variousV views' of the drawings, similarv reference charactersdesignate similar parts.`

Where cutters are employed, or similar' instruments", .it is necessary vto clamp the paper or other material firmly While it isv being operated upon. The thickness of this material Will vary Within' the limits of the apparatus and in many instances it is also necessary to have either' an automatic power clamp' which Will accommodate itself to any thickness Within the scope of the machine,l and ainanual clamping which will be under the control of an operator so that the ma'-l chin'e' may be used either way. 'Further-A more, this machine must always be reliable and accurate in its operation as any failure in the machine may-be disastrous to the operator, the material or the machine. @ne embodiment of my invention Which meets these'conditionswvill now be described.

A inachine l of the type in question is provided With a table 2 carried loy any suitable support as side frames with parts 4 above the table which carry a clamp 5 and a knife' 6 in the conventional manner. This knifev 6 may be. driven in 'any suitable Way as lloy links 7, crank pins 8 `and' cranks 9 seeuredto a'shaft 10 which may be driven by any suitable source of po-vver, not shown, and al1 of which',ishonventional. The knife may also be guided by a diagonal link ll which causes it to make a shear out. i

Of course, the knife mechanism may be Varied, as desired and modifications are not shown, as all such structures are old and 'Well known in the art and form no part of this invention. It may be that a punch may be substituted for the knife in which case there would be no draw cut. These or any other desired devices may be used, as Will be understood, without fui-ther reference or description.

The' clamp 5 is actuated by mechanism lwhich w'ilinow be described. In the enibodinient shown this eianip is secured ai each end to racks 12 which mesh With segmental gears lswhieh are fixed to a shaft 14 and this shaft is 'surrounded in part by ai coil spring' l5 which has one end Xed in the gear 13 andthe other 'end is fixed in a Hangs 1'6 which depends from thetable This spring acts'as acounterweight so as body 37. soas not Eil Cil

to keep the clamp raised under normal conditions, and when this clamp is lowered to 'lunction as a clamp in a manner which will' be described below, this spring 15 is in tension with suiiicient power to raise the clamp whenever 'the lowering mechanism is released. lf desired, a counterweight could be substituted tor this spring 15, as is obvious.

At one end, orany other convenient location, the shaft 14 is provided with a sprocket wheel 17 which carriesa sprocket chain 18 which runs over an idle sprocket wheel 19 mounted on a stud shaft 20 which extends from one of the supports 3 and from the wheel 19 the chain 1S runs to a segmental sprocket wheel 21 fixed on the pedal shaft 22, which is pivotally mounted in the pedes tais 3 of the machine. This shaft 22 carries a toot pedal 23 of the conventional kind. Normally this toot pedal is kept raised by a suitable spring 24 mounted 0n the stud shaft 2O and secured at one end to a frame l3 and at the other to the wheel 19. `When the toot pedal 23 is depressed the tension of this spring24 is overcome and also the tension ot the spring 15 and the shaft 14 is turned so as to drive the segmental gears 13 which in turn lower the racks 12 and cause the clamp 5 to Vfunction on any material 25 that may be placed on the table 2.

@ne segmental gear 13 has curved arms 26 spaced at any convenient distance apart, and one of these arms is extended at 27 to engage a stop 23 on a side frame 3 so as to limit the upward movement of the clamp 5. Both of these arms have a suitable pivotal connection b29 with the arms 30 of a yoke 31 which is composed of these arms and a con necting shaft 32. Between the arms 30 the shaft 32 passes through a bearing 33 which forms an integral part of a member 34 which has a collar 35 and a plunger 36. The plunger extends into a cylinder or body 37 and the collar 35 normally rests on a washer 33 which is sandwiched in between this collar and the body 37 and just above the to rest thereon, but it does rest on the top of a sleeve 39. This sleeve is preferably made in two parts which are held in proper relation by means of clamping bolts 40 with nuts 41 which may be adjusted thereon so as to put more or less pressure on the tension springs 42 which yare placed on said bolts. To maintain a proper connection between the body 37 and the sleeve 39, l provide a suitable lining A43 oi leather or any other suitable material, which is preferably put in a recess formed for the purpose so that it will lie true and remain true at all times. This sleeve is also provi-ded with two sets of guides at right angles to each other. One set 44 permits the pivots 29 to slide 'freely therein and the other set receives the spiral racks 45 which move freely therein and are kept in place by the cover plates 46 which are held by screws 47 or any other suitable means. The lower end of the sleeve 39 rests on a suitable iibre washer 48 which rests on a hardened steel washer 49 and both of these surround the reduced lower end of the body 37 and the lower washer 49 rests on a spiral gear 50 which engages the spiral rack bars 45 and is turned by them as it rises and falls in a manner which will be described below. It' desired, the washers 48 and 49 may bereplaced by a ball bearing or a roller bearing. The'lower end of the spiral gear 50 has a pawl and ratchet connection 51 with the body 37. ln the embodiment of my invention shown yin Figures 4 and 5 the body 3T has spring pressed pawls 52 extending in opposite directions along the same diameter so as to engage the teeth 53 which are fixed so as to proJect inwardly into a recess at the bottom of the gear 50. rlhese ratchet teeth are preferably given an odd number so that one of the pawls 52 will be in engagement with the teeth twice as often as they would be in engagement if an even number of teeth were employed. ln Figure 9 is shown an ordinary roller ratchet 54 with springs 55 to force the rollers into engagement with the smooth interior 56 which takes the place ofthe teeth 53. The advantage of this ratchet is that it will instantly engage at any point and permit no lost motion of any kind whatsoever and so this is the preferred embodiment of my invention. However, while I have shown two ratchets, it is obvious that` any suitable form of ratchet may be employed.

The lower end of thevbody 37 and the lower end oi' the spiral gear 50 are closed by means of a suitable cover plate 57 which is securedV to the body 37 by screws 58, ork

other suitable means, so as to conceal and protectthe ratchet 51 with a working joint and this cover plate 57 has a conical collar 59 which enters corresponding recess in the bottom of the spiral gear 50 so that on the return movement this spiral gear when turned by the rack bars 45 rwill not turn too freely on the body. l

The spiral racks 45 slide freely in the recesses under the cover plates 46, as above stated, and they are provided at their upper ends with stop pins 60 which prevent ya separation of these rack bars 45 Jfrom the sleeve 39 as might occur when the clamp is manually operated, as described above, if these pins were omitted. The lower ends vof these ra k bars 45 are secured to a bearing 61 which engages a Vcrank pin 62 on a gear 63 which is mounted on a stud shaft 64 which extends from a Vtraine 3 and this gear 63 meshes with a gear 65 with the same number of teeth which is iixed to the main shaft 10 of the machine. O1 course, this is only one Vsleeve 39 and then the y'resistance due tothe way of driving the pitman 66 which connects .the crank pin 62 with the yoke `3l which has been Any other suitable mechanism lmay be used for driving. It is essential that it be driven so as to elongate and contract in a manner which will be described below, and provided this occursit. may be connected and driven in any suitable manner.

In the embodiment of my invention shown in Figure l0 the pitman '66 is driven by an eccentric 67 on the main shaft l0 and the yoke 3l drives a bell crank lever 68 mounted on a rocker shaft 69 and this lever drives links'70 that runs to arms 26 ofthe gears 13 through which the racks l2 are driven as above described. Y

Operation.

In view of the foregoing, the4 operation'of my improved clamp will be readily understood. vIf the operator wishesv rst fto bring the clamp, down on the. material to be clamped by manual effort, he depresses the foot pedal 23 in the conventional manner and then the sprocket chain 18 functions so as to draw theclamp down on the work, as above described. The operator thenapplies power in the usual manner and the shaft l0 is driven and brings -down .the knife through the connections above described and simultaneously drives the gears VV and 63 and the greater, to raise this greater part until the shoulder 35 and washer 38 of the `plunger rest lon the material 25 is encountered and as lsoon-as this resistance is encountered the spiral racks 45 begin to turn-the spiral gear. 50 thereby 'causing' frictionbetween the leather 43 in the sleeve 39 and the body 37'w-hich isproportional to the tension ofthe springs42 which is imposed by the nuts 4l and may be whatever is desirable forproperv clamping. This permits a proper pressure of the clamp for any thickness of material, the lost motion being taken up by the spiral racks 4:5 and theA frictional engagement above mentioned, and this continues until the limit to the stroke is reached, it being understood that the body 37 must turn because it is positively driven from the gear 50 through the ratchet 5l. As soon as the limit of the movement of the pitman 66 is reached and that is as soon as the knife 6 has finishedl cutting or operating, the pitman begins its reverse movement and the instant it starts to reverse the knife 6 rises also andthe clamp 5 rises under the inuence of the spring 15 while the pitman releases at the ratchet 51 and allows the racks to turn the spiral 50 on the return movement without in any way turning the body 37 andas this turning occurs, the only resistance to the turning ofthe gear 50 is the vconical Vcollar 59 secured in the' cover 57 which is.

described in detail above.v

part of thepitman 66 so asl fixed vto the Vbody 237 sothat during the return movement, the pitman 66 assumes its most extended position and then when its movement is finished the automatic mechanism which is generally employed in such machines brings both .the clamp andthe knife toy rest and' the clamp rests at the upper limit of its movement,` as determined bythe position of the stop 38. It is apparent that the resistance of the spiral gear to its reverse movement causes a resistance to an elongation of the.A pitman 66 and vthis resistance causes additional stresses on the parts 31 and 62 connected to the pitman and soremoves apart or all of the clamp lifting loadfrom vthe spring l5 to the crankipin 62 so that if desired, by tightening the screws 58 and making the plunger 36 tight in the body 37, the spring l5 may be dispensed with. Of course, this limit should be below Vthe Vlower edge of the knife which should never be in a position to cut the hand of the operator.v

That/mit 8yst`em.`,

Inthe foregoing has been described some automatic devices including the pitman-for a cutting' machine. These are suitable for small machines, say i thirty-two? Ainch machines. "Where machines are larger, as forty, fifty, or ninety or onehundred and twentyeight inch machines, it is obvious that thev clamp must be operatedwith more clamping power and then' it is necessary, to employ onev or more pitmans, all of which may be connected in any suitable manner, as in duplication-ofthe manner shown, so that 'this invention can be and it is not infany. wayv limited tothe prev cise connectionsjherein shown and described, nor is it limited in any way to the precise form` herein shown and described, but is broad enough to come within the scope of the annexed. claims.

Having thus described my invention, what I claim is:

l. Ina machine of the class described, a table, a clamp adapted tohold a substance ontheKt-able and means for actuating said clamp including in its construction a spiral gear device which shortcns and el-ongates while functioning and has vparts in frictional engagement while 'clamping and free while releasing. y 2. In a.machinelofthev class described,i a table, -a clampy adapted. to hold a substance against said table and mechanism'for vactuating said clamp 'automaticallyembodying in "its construction a pitman which shortens cover all structures that y table, a clamp adapted tov force a eating parts,

and elongates while functioning and clamps itself so as to be nearly rigid vwhile shortening and releases while elongating.

3. In a machine of the classdescribed, a table adapted to hold a substance and a clamp adapted to force the substance against the table and means for actuating said clamp embodying in its construction a pitman which moves in two directions and is provided with reciprocating and rotating parts which are adapted to function so as to clamp while on one movement and torelease while on the other movement.

. a. In a machine of the class described, a substance against said table and holdthe same and means for actuating said clamp embodying in its construction a pitman with reciprorotary rparts and frictional parts, these three vparts .being so arranged and disposed that the pitmanlfunctions while clamping with a force proportional t-o the frictional resistance of the parts and freely releases when not clamping.

5. In a machine of the class described, a table, a clamp adapted to hold va substance on the table and means including'a pitman moving in two directions for actuating said Gil y clamp, such pitman being provided with elatively movable partsV which engage with frictional contact while moving in one direc tion'and while the clamp Yis clampingA and without such contact whenV moving in the other direction, thus allowing' a free release of the clamp when not functioning as a clamp. Y

QIn a machineof the class described, a table, a clamp adapted to hold a substance on the table, means including a pitman moving in two directions k'for actuating said clamp, such pitman being provided with relatively movable parts which engage with frictional contact while moving in one direction and while the clamp is clamping and without such contact .when moving in the otherdirection, thus allowing a free release of the clamp when not functioning as a clamp and manually controlled means for actuating the clamp and releasing the same from the first mentioned means'while acta.V ated by the manually controlled means.

7. In a machine of table, a clamp adapted to khold a substance Lon the table and means for actuating said clamp including in its construction a pitman which shortens and elongates while functioning and has parts in frictional engage-` ment while clamping and free while releasing, one of said frictional parts of said pitman being provided with a spiral gear with Y a ratchet connected thereto, saidgear being driven by at least one'corresponding rack which also forms apart of the pitman.

8. In a machine of the class described, a

' table, a clamp adapted to hold a substance the class described,`a

von the'table and means for actuating said sleeve with a suitable frictional surface such.

as leather, a body with va second surface engaging said frictional surface, a spiral gear connected to said body with a ratchet connectionand means for rot-ating said spiral gear.

9. In a machine of thevclass described,'a table, a clamp adapted tok hold a substance onthe table and means for actuating said clamp including in its construction a device which shortens kand elongates while functioning and has parts in frictional engagement while clamping andkfree while releasing, said parts having YKspring controlled means subject to adjustment, whereby the tension of the clamping means maybe varied 7ithin limits, Vas desired, by varying the pressure of'the frictional contact ofA said partsv and means for causing one of said parts to move with regard to the other while the clamp is functioning and means for permitting a free release from such driving means when the clamp isnot functioning.

10. In a machine ofthe class described, a

table, a clamp adapted to hold a substance eans vfor actuating said ing. mechanism so ,thatY when the clamp is driven by other means than the actuating means above mentioned, this plunger may shift Vwithout causing such actuating means to function.V f

11. Ina machine of the class described, atable, a clampadapted Vto hold a substance on the table, means for actuating Ysaid clamp `including in its construction a spiral device which shortens and elongates while functioning'and has parts in frictional engagement while clamping and free while releasing kand a stop for llimiting the upward movement of said clamp upon releasing.

12. In a machine of the class described, a pitman'providedl with one or more spiral rack bars, a spiral gear engaging said bar or bars, a ratchet connected to said spiral gear, a frictional body driven by said ratchet in said spiral, a sleeve with a frictional surface engaging said body and also said rack or racks and means forV connecting said body with mechanism to'be driven. v l V13. In a machine oflthe class described, a pitman comprising one or more spiral rack bars, a spiral gear driven by said bar or bars, a body having a ratchet connection With said spiral gear, a sleeve With a frictional surface engaging said body and also said bar or bars, means for varying the pressure of said frictional parts and means for connecting' said body With mechanism to be driven by the pitman.

14. In a machine of the class described, a pitman provided With one or more spiral racks, a spiral gear engaging said rack or racks, a body connected to said spiral gear by means of a ratchet connection, a sleeve With a frictional surface engaging said body and also said rack or racks, a plunger adapted to move in said body, a yoke With depending arms pivotally mounted in said plunger and driven mechanism connected With said yoke, said driven mechanism forming also a guide for said yoke and one end of the pitman. v

l5. In a machine ofthe class described, a table, a clamp adapted to hold a substance on the table and means for actuating said clamp including in its construction a spiral device to be' used in multiple units Which shortens and elongates While functioning and has parts in frictional engagement While clamping and'free While releasing.

In testimony whereof, I have hereunto set my hand this 25th day of May, 1923.

JOHN F. SCHROETER.'

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