US1960678A - Clamping device for printing plates - Google Patents

Description

May 29, 1934. s. w. MARVIN CLAMPING DEVICE FOR PRINTING PLATES Patented May 2 9, 1934 UNITED STTES a rcr.

one-third to William J. Marsh, Concord, Mass,

and one-third to Charles G. Wells, Boston,

Mass.

Application September 17, 1932, Serial No. 633,592

4 Claims.

This invention relates to a clamp or gripping device for use with the bed block of a printing press having slots or channels in the upper surface thereof, and in which slots or channels the clamp or gripping device is bodily movable lengthwise of the slot or channel toward and from a printing plate on said bed block.

A clamp or gripping device of this character is shown and described in U. S. Patent No. 1,628,384 granted to me May 10, 1927.

The present invention is an improvement upon the clamp or gripping device shown in the patent referred to and has for its object to provide a clamping device, which is materially simpler, less expensive and equally efficient, and which can be quickly manipulated, whereby the printing plates on the bed block may be adjusted thereon and secured thereto by the operator in a minimum time.

To this end, the clamping device embodying this invention is provided with a bar or member insertible into the slot or channel in-the bed block and slidable lengthwise of said slot or channel, and is further provided with a rotatable member which is carried by said bar'and' is adapted by rotary movement to be engaged with one side wall of the slot and to cause the bar to be engaged with the opposing side wall of the slot so as to secure the clamping device in fixed relation to the bed block.

The bar or member slidable in the slot is also provided with a catch or member extended transversely thereof above the same for engaging the printing plate, and said bar is preferably provided with a second member extended transversely thereof which co-operates with the catch to form a guideway for a tool by which the rotatable member is rotated.

These and other features of the invention will be pointed out in the claims at the end of this specification.

Fig. 1 is a plan of a bed block of a printing press with a printing plate secured thereon by clamping devices embodying this invention, one of the clamping devices being shown by dotted lines out of engagement with the printing plate;

Fig. 2, a plan on a larger scale of one of the clamping devices shown in Fig. 1, and a portion of the bed block;

Fig. 3, a plan of the clamping device shown in Fig. 2 with the rotatable clamping member in its operative position;

Fig. 4, a side elevation of the clamping device shown in Fig. 2 looking in the direction of the arrow thereon;

Fig. 5, a View like Fig. 4, with the rotatable clamping member removed;

Fig. 6, a detail in plan of the rotatable clamping member shown in Figs. 1 and 2;

Figs. 7 and 8, plan view of modifications to be referred to;

Fig. 9, a sectional view tion to be referred to;

Fig. 10, a side elevation of one form of tool for of a further modificae operating the clamping device shown in Figs. 1

and 2, and

Fig. 11, an inverted plan of the tool shown in The clamping devices in accordance with this invention are provided with a bar or member 16, which is insertible into the slot or channel 13 and is slidable lengthwise thereof, and said bar or member 16 is designed to be engaged with one wall as 14 of the slot 13 and will be hereinafter referred to as the slidable clamping member of the clamping device.

The bar or member 16 carries a rotatable clamping member which is designed to be engaged with the opposing wall 15 of the slot 13 and in the preferred construction shown in Figs. 1 to 6, the rotatable clamping member is formed by the head 18 of a'screw or shaft 19 in engagement with a threaded socket or bore 20 in the sliding clamping member 16 which bore is located below the upper surface of the sliding clamping member and is'extended transversely of the latter. The head 18 of the screw 19 is provided on its circumference with gear teeth 22, some of which project above the upper surface of the sliding clamping bar 16, so as to be capable of engagement by a suitable tool shown in Figs. 10 and 11, said tool having a blade 24 provided on its under side with teeth 25, which in the present instance are shown as inclined with relation to the blade. The teeth 25 are designed to be engaged with the teeth 22 of the rotatable clamping member, and by movement of the tool transversely of the slidable clamping member 16 in the direction indicated by the arrow 26 in Fig. 2, the rotatable clamping member is rotated in such direction as to move the toothed head 18 out of a socket 28 in one face of the bar or slidable clamping member 16 after the manner represented in Fig. 3, and by such rotation of the toothed head of the screw, the said head is brought into engagement with the wall 15 of the slot 13 and further rotation of the toothed head is limited by the wall 15 and effects movement of the slidable clamping member or bar 16 against the wall 14 with sufiicient force to cause the clamping device to be firmly pressed against the vertical walls of the slot.

Movement of the tool in the direction opposite to that indicated by the arrow 26 in Fig. 2 effects rotation of the rotatable clamping member 18 in the opposite direction and effects disengagement of the clamping device from the walls of the slot. The operating tool 24 is provided with a suitable handle 29 (see Fig. 10).

Provision is made for guiding the tool 24 in its movement to effect rotation of the toothed head :18 of the screw 19, and to this end the slidable bar 16 has secured to or forming part thereof two cross members or bars 30, 31, suitably spaced apart to ensure the engagement of the teeth 25 of the tool with the teeth 22 of the rotatable clamping member 18 during the movement of the tool to effect rotation of the rotatable clamping member. The cross bars 30, 31 are preferably pro- Vided on their outer sides with inclined surfaces 32 (see Fig. 4) which co-operate with a bevel or inclined edge 33 of the printing plate and thereby form stationary catches which engage the plate and serve to firmly clamp the plate onto the bed block.

In the construction shown in Figs. 1 to 6 the toothed rotatable clamping member 18 is shown as fixed to the screw or threaded shank 19 so as to rotate as one piece, the movement of the rotatable clamping member outwardly from the block and into engagement with the wall of the slot being effected by the rotation of the threaded shank 19 of the screw in the threaded bore or socket 20 in the bar or slidable member 16..

While this construction may be preferred, it is not desired to limit the invention in this respect as the toothed rotatable clamping member 18 may be mounted to turn on the shank or threaded shaft 19, after the manner represented in Fig. 9, and in this latter case the threaded shaft on which the toothed member is rotated may be stationary with relation to the sliding clamping member 16.

.So also it may be preferred to provide the rotatable clamping member 18 with teeth 22 on its outer circumference, but it is not desired to limit the invention in this respect, as the rotatable clamping member 18 may be provided with an untoothed or smooth circumference having suitable sockets or holes 35 shown in Fig. 7, by which the rotation of the clamping member may be effected by means of a pin or other suitable tool, not shown.

While it may be preferred to have the rotatable clamping member 18 normally located within a socket in the slidable clamping member 16 as represented in Fig. 2, it is not desired to limit the invention in this respect, as the rotatable clamping member may be located outside of the sliding member after the manner represented in Fig. 8.

The operation of the clamping device may be briefly described as follows:

'The bar or slidable member 16 is inserted into a slot 13 in the bed block and after the printing plate has been laid upon the bed block, the operator places the toothed blade 24 in the guideway formed by the stationary catches 30, 31 and engages the teeth 25 of the tool with the teeth 22 of the rotatable clamping member 18. At such time the block or slidable clamping member 16 is free to move lengthwise of the slot in the bed block and this lengthwise movement is effected by means of the tool 24, the handle 29 of which is grasped by the operator and moved toward or from the printing plate on the bed block.

By movement of the handle of the operating tool toward or from the printing plate, one of the catches as for instance the catch 30 is engaged with one edge of the plate 12, and when thus engaged the operator moves the tool transversely of the slidable clamping member 16 in the direction indicated by the arrow 26, Fig. 2, and effects rotation of the rotatable clamping member 18 so as to cause the rotatable clamping member to engage the wall 15 and thereby cause the sliding clamping member 16 to be engaged with the wall 14 of the slot and in this manner firmly secure the clamping device in fixed relation to the bed block with the stationary catch 30 or 31 in engagement with the printing plate.

When the clamping device is thus properly positioned, the operator removes the tool and performs the same operation on another clamping device.

The printing plate is usually clamped on its opposite sides by two or more clamping members, and the stationary catches 30, 31 of those clamping devices which are to co-operate with the sides of the plate are arranged so that the clamping member 31 can be used to engage the plate on the left hand side of the plate, viewing Fig. 1, whereas the clamping member 30 engages the right hand side of the printing plate.

Clamping devices are also used at the top and bottom and when thus used, the stationary catches 30, 31 are arranged transversely of the sliding member or bar 16 after the manner represented in Fig. 1 at the top and bottom of the printing plate.

When it is desired to remove the printing plate, or to adjust it on the bed block, the clamping device may be released by engaging the tool 24 with the rotatable clamping member 18 and moving the said tool in the direction opposite to that indicated by the arrow 26, after which the clamping device may be moved in the slot 13 in the bed block away from the printing plate, and into a position such as indicated by dotted lines in Fig. 1. The clamping device may then be rendered stationary on the bed block by moving the tool 24 in the direction indicated by the arrow 26.

From the above description, it will be seen that the clamping device is composed of a minimum number of parts, and may be manufactured at a minimum cost. It will also be observed that the clamping device can be quickly and easily operated and when in operative relation to the printing plate effectively secures the latter to the bed block.

What is claimed is:

1. A clamping device of the character described having, in combination, a slidable clamping member capable of being inserted into a slot in the upper surface of the bed block of a printing press L and of sliding lengthwise of said slot, a rotatable clamping member carried by said slidable clamping member and adapted to be engaged with one wall of said slot and effect engagement of the slidable clamping member with the opposing wall of said slot, and cross members secured to said slidable clamping member and extended transversely thereof to form a guideway through which said rotatable clamping member is accessible from above the bed block.

2. A clamping device of the character described having, in combination, a bar capable of being inserted into a slot in the upper surface of the bed block of a printing press and of sliding lengthwise of said slot, a shaft carried by said slidable bar and extended transversely thereof below the upper surface of said bar, a head on said shaft provided on its circumference with teeth extended above the upper surface of said bar to be engaged by a tool movable transversely of said bed block, and means on said bar for guiding said tool as it is moved transversely of the bar to rotate the toothed head in the direction of the length of said slot.

3. A clamping device of the character described having, in combination, a slidable clamping member capable of being inserted into a slot in the upper surface of the bed block of a printing press and of sliding lengthwise of said slot, a shaft carried by said slidable clamping member and extended transversely of the slidable clamping member below the upper surface thereof, a device mounted on said shaft and provided on its circumference with teeth extended above the upper surface of said slidable clamping member and out of said slot to enable said device to be rotated in the direction of the length of said slot by a tool movable transversely of said slot and above said bed block, and means for guiding said tool in said transverse movement.

4. A clamping device of the character described having, in combination, a clamping member slidable lengthwise in a slot in the upper surface of the bed block of a printing press and adapted to engage one wall of said slot, means on said clamping member for forming a guideway for a tool movable with said clamping member in the direction of the length of the slot and movable in said guideway transversely of the clamping member, and a rotatable toothed device carried by said clamping member and arranged with relation to said guideway to be actuated by movement of said tool transversely of said clamping member to secure the latter in fixed relation to said bed block.

SAMUEL W. MARVIN.

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