US935439A

US935439A - Clamp for flexible printing-plates.

Info

Publication number: US935439A
Application number: US49658709A
Authority: US
Inventors: Joseph White
Original assignee: HALL PRINTING PRESS Co
Current assignee: HALL PRINTING PRESS Co
Priority date: 1909-05-17
Filing date: 1909-05-17
Publication date: 1909-09-28
Anticipated expiration: 1926-09-28

Description

J. WHITE.

CLAMP FOR FLEXIBLE PRINTING PLATES.

APPLICATION FILED MAY 17. 1909.

Eatented Sept. 28, 1909.

JOSEPH WHETE, PRESS 6033523..

To all whom it may concern."

Be it known that l, osii zexrof the United State 1 brook, Somerset (aiuuty, State or .a sey, have invented certain new and useful Improvements in tlamps tor Flexible Printing-Plates, fully described and illustrated in the following specification and accompanying drawing.

The object of this invention l simplify the mechanism for clamping and adjusting the plates to a bed or supporting surface, and to facilitate the manipulation of the parts so that a plate may be more quickly put in, adjusted to or removed from a printing machine than has been hitherto possible; and while the device is prii'narily intended to hold flexible printing forms in a printing machine, it also will be used for holding a printing blanket of rubber or other material.

Referring to the drawing in which like characters of reference indicate the same parts, Figure l is an end view of a printing cylinder showing a pair of the clamps to hold a flexible printing plate, one of said clamps being in :tion, 4 taken in the direction of the arrow of 1, some of the parts being shown in section.

Referring to Fi 1 a. printing plate 1 of zinc or aluminum is stretch l and. adjusted onto the bed 2 by means or hereafter described; this bed lS shown in the form of a segment 2 of a cylinder (although the device might be employed in connection with a fiat surface) and has bearing 3 formed at its sides against which the clamps reactin order to stretch the plate on the bed. These bearing faces are former on oneslde of thegaps reaching across cylinder which have fastened :in them by means of a series of screws 4, the bearing blocks 5, in which the trunnions (S, of the plate clamps find their bearings.

A plurality of clamps is preferably employed on each end of the plate, although under certain conditions one pair o1 clamps could be used or onFt-lamp conic hold one side of the plate, the other side being held to the cylinder by any other means. These clamps as illustrated, consist of a member on which the trunmons G are formed, part of which mcmbcr conslsts oi a web '7 (on the .cnd of which a face 8,} which forms the rigid jaw between which and the morabl l ig. 2 is View s to be application files 17, E99.

Patented Sept. 28, 1.909.

Serial No. 496,587.

and 13 .upon which is pivoted a member in the form of an angle plate, one wing f) of which extends over the face 8 ot the rigid jaw and acts as the movable jaw of the clamp, the other wing 14 which lies approximately parallel with the web '1, has a thumb screw 15, which bears against the web 7 of the clamp and'tends to rock the movable jaw on the

pivots

12 and 13, thus gripping the sheet between the jaws 8 and 9. The function of this screw 15 is to cause the jaws to close as described, but it can be seen that .various devices might be employed to cause reaction between the movable jaw and the fixed jaw, whereby the jaws will close to grip the sheet, but .the device illustrated and described is the-preferable one. \Vhen the sheet is gripped between the jaws, it is then necessary to adjust and strain the plate on the supporting bed.

The clamp A at the bottom of Fig. 1 is shown in the position of gripping the sheet, the clamp ll in section in Fig. l is shown open; this clamp will now be rocked i'or- \YZUTII'SO that the plate will be betwccn the jaws of the clamp B, the thumb scrcw will then be manipulated, temporarily cl amping the jaws wer the plate.

in order to properly st -ain the plate to its supporting bed, a device for causing a reaction between the hearing face 3 movable jaw is used, which might be constructed in various ways but the prcfcrrcil form is shown; the pivoted jaw has mounted in it the bolt '16 which passes through the clearance hole 17 in the fixed jaw and which when turncdwill bear against the face 3 of the printing bed, and force tho,clamp away from it and strain the plate to its surfacc.

lly the peculiar construction, illustrated and shown, it is only necessary to lightly set the jaws of the clamp by means of the wing screws 15, which form an auxiliary means for clamping the platc. The. primary means is applied by the bolt it), which whcu and thc lurncd to force the (lamp away 'l'rom llH jaws and the plate (due to the tension applied by the thumb screw 15) sufficient to hold the plate from slipping in the jaws.

.It can be seen that the thumb screw 16 has'coiled around its stem, a spiral spring 18,- which is wound .up by the thumb screw when a plate is clamped between the movable jaw and the lower jaw; the friction of the screw against the body of the clamp is sullicient to prevent it being unscrewed by the coil spring, but when the bolt 16 is tight cued and the sheet strained to its surface, the stress of the plate in tension causes the jaw 9 to be rocked slightly on its pivots, and the thumb screw' 16 in the wing 'l-l, which has been lightly pressing" against web 7 ol' the. clamp, is released from contact. with web 7, and the spring 18' unwinds to unscrew the thumb screw.

When screws 15 are released from pressure against, the fixed jaws both sets ol clamps A and B will still hold the plates tightly. and securely by means of the primary clamping and straining stress described, and when it is time to remove the plate when a job is finished, it is only necessary to loosen the screws 16 of" the clamps in one of the gaps to'release the grip of all the jaws holding the sheet, thus releasing the late for removal from the press.

The devices shown in the drawings and described hereinare the preferable forms embodyingthe featuresof this invention; the elements embodying it may be widely varied in construction 7 without departing from the principles specifically mentioned in the Following claims.

The claims:

'1. The combination with a supporting surface for a lleXiblc sheet. of a clamp to grip said sheet. and strain it to the. supporting surface, and a member .in connection with said clamp operating to cause the. clamp to grip and strain the sheet; said clamp so arranged that when said member is operated to release the strain of the sheet upon the supporting surface the grip of. the clamp on the sheet will also be released.

2. The combination with a cylindrical supporting surface for a flexible sheet, of a clamp to grip said sheetand strain it. to the supporting: surface, and a member in connection with said clamp operating to cause the clamp to grip and strain the sheet; said clamp so arranged that when said member is operated to release the strain upon the supporting surface the grip of the clamp'on the sheet willalso be released;

The combination with a supporting surface for a licxible sheet, of a pivoted clamp having a pair of jaws to grip the sheet and strain it to the supporting surface, a member in connection with said clamp ope 'ating to rock the clamp to strain the' sheet, and close the jaws to grip the sheet; said clamp ing so arranged that when said member is cp erated to release the strain of the sheet upon the supporting surface the grip of the jaws on the sheet wili also be released.

4. The combi'natioi'i with a supporting sur- 3 face for a flexible sheet, of a pivoted clamp to hold said sheet and. strain it to the supporting surface, said clamp having a ri jaw and a movable jaw; means appli -e the movable jaw whereby a stress exei ed. to 7; strain said sheet to the supporting surrace, will also grip the sheet in the jaws of the clamp.

5. The combination with a supper 3 Face for a liexible. sheet, of a pair of o; ing clamps, each having a pair of sheet ping jaws. means on each of the clamps tor causing the jaws to "grip the sheet, means also moving the clamps tes ers in the sheet to the supporting surface and said 3- means so arranged that when they are open ated to release the strain otthe sheetupon the supporting bed the grip of the wiii' also be relaxed.

(l. The combination with a supportinghed 9 for a flexible sheet, of a. movable ciamp to.

hold said sheet and strain it to the support-- in bed. av hearing,- face at the end of the bed; said clamp having a rigidjaw a movable jaw. means applied to the inovabie jaw ot the clamp and acting against the bearing face, to clamp the jaws and move the clamp to hold and strain the sheet.

7. ,'.lhc combination with a snpport tor a flexible sheet, of a pair of clamps to hold said sheet and the- .supporting bed, and bearing each end of the bed said clamps eachl a movable jaw and a rigid jaw, means 1 1.}.3 plied to the movable jaws of each eiamp and acting against the bearingwtaces of the bed, whereby the sheet is ripped between the'clamp jaws and the clamp is moved to strain thesheet to the'bed.

St The. combination with a supporting having bearing-faces on its opposite of a pair of opposing clamps each pair of gripping jaws, actuating meant plied to one ot the jaws of each of posing clamps and acting against. the

faces for causing the jaws to grip sheet and also strain the sheet, to su porting surface! .aid cl: mps so arrat that when the aetuatingmeans of one t clamps is operated to release the strain at the plate on the bed, the gri of the jaws both clamps will be release 9. The combination with a supporting for a flexible sheet, said bed having a. bearing; surface in enchcf a movable clamp, i 1-- ing a rigid jaw and a movabie jaw, auxiliary means acting between the movable jaw and, the rigid jaw to hold said sheet in the rip said jaw and primary means actine' betweni the movable jaw and bearing face or the bed,

whereby the stress exerted to strain said sheetto the supporting bed, will also hold the sheet in the clamp,

10. The combination with a supporting bed for a flexible sheet, said bed having hearing faces at either end, of a pair of opposing clamps each having a rigid jaw and a movable jaw, auxiliary means acting between the movable jaw and each rigid jaw of each clamp, to hold said sheet in the grip of said jaws and primary means acting between the movable jaws and bearing faces of the bed. whereby a stress exerted to strain said sheet to the supporting bed will also hold the sheet in the clamp.

11. The combination of a supporting bed for a flexible sheet, of a movable clamp to hold said sheet and strain it' to the supporting bed, said bed having a bearing 't'aee, said clamp having a rigid jaw and a pivoted jaw. a screw in the pivoted jaw moving said jaw to the sheet, another screw in the pivoted jaw, acting against the bearing face for moving the clamps to strain the sheet to its sup porting bed.

vl2. The combination bed for a flexible sheet. of pivoted clamp having a rigid jaw and a movable jaw, said supporting bed having a bearing face at its end, said clamp having a screw acting between the rigid jaw and the movable jaw to grip the sheet, and another screw on the with a supporting movable jaw acting against the bearing t'ace.

to rock said clamp, to strain said sheet to the supporting bed and also hold the sheetin the clamp.

13. The combination with a supporting surface for a flexible sheet, of a clamp to grip said sheet and strain it to the supporting surface, primary and auxiliary means on said clamp f0 actuating the sheet gripping means and operating means for the auxiliary means, said operating means arranged to re lease the auxiliary means on the application of the primary means.

l t. The combination with a supporting bed for a flexible sheet, of a movable clamp to hold said sheet: and to strain it to the supporting bed and a bearing face at the end of the bed; said clamp having a movable jaw and a fixed jaw, auxiliary means acting between the movable jaw and the fixed jaw to cause the jaws to grip the sheet, and primary means acting between the movable jaw and the bearing face to cause the jaws to grip the sheet, and means arranged to release the auxiliary means on the application of the primary means.

In witness whereof, I have hereunto set my hand in the presence oi two subscribing witnesses.

JOSEPH XVII ITE.

llitinesses v Lnwis R. Sonornnm, lnnar V. HALL.