US2599602A - Mechanism for registering sheets - Google Patents

Description

June 10, 1952 H. T. BACKHOUSE MECHANISM FOR REGISTERING SHEETS Filed July 29, 1947 Patented June 10, 1952 MECHANISM FOR REGISTERING SHEETS Headley Townsend Backhousc, Wentworth, England Application July 29, 1947, Serial No. 764,599 In Great Britain February 23, 1945 Section 1, Public Law 690, August a, 1946 Patent expires February 23, 1965 1 Claim.

This invention comprises improvements in or relating to mechanism for registering sheets being fed to printing presses and other machines.

The invention relates to sheet registerin mechanism of the type (hereinafter referred to as the type described) comprising a layboard. means such as a tape conveyor for feeding the sheets over the layboard, one or more lays against which the front edge of each sheet in turn is fed to register the position of the sheet before it is taken by the printing press or other machine, and suction grippers (acting as smoothers) operating above the layboard and arranged to grip the upper surface of each leading sheet and to move with it up to the front lays.

The purpose of the suction grippers in mechanism of the type described is to overcome the difficulty, which sometimes arises when such grippers are not employed, particularly when sheets are being conveyed at high speed, that the leading sheet may arrive for registration at the front lays a little too early or too late in relation to the timed cycle of operations. In the former case the sheet may buckle and spring back from the front lays and in the latter case the sheet may be taken by the grippers or equivalent devices of the printing press or other machine before there has been time to effect registration between the front edge of the sheet and the lays. In both cases inaccuracies in registration may result.

According to the present invention suction grippers operating above the layboard and acting as smoothers are used in conjunction with preliminary sheet stops which travel with the grippers toward the front lays.

The invention accordingly consists in sheet registering mechanism of the type described characterised by preliminary sheet stops operating above the layboard and arranged to travel with the suction gripper elements towards the front laysof the printing press or other machine to effect a preliminary registration of the sheets while they are gripped by the suction gripper elements.

An example according to the invention will now be described with reference to the accompanying drawings (partly diagrammatic) in which:

Figure 1 is a perspective view (with parts broken away for the sake of clearness) showing the essential elements of the apparatus, and

Figure 2 is a longitudinal cross-section of a combined suction smoother element and preliminary sheet stop.

Like reference numerals indicate like parts in both figures.

In this example there are two suction grippers (of which only one is shown in the drawings) spaced apart across a layboard ill at positions to engage the leading edge H of each sheet l2 as it approaches the front lays I3 (only one of which is shown in the drawings) which are positioned at the forward end of the layboard Ill and are operable in usual manner. Each gripper is constituted by a box-like element Hi carried at the end of a forwardly-extending tubular arm 15 located above the layboard. Each gripper i4 is provided with a multiple point suction mouth 16 communicating by an interior conduit H with the bore of the tubular arm 15. Each preliminary sheet stop-one being associated with each gripper l4-is in the form of an angle-shaped finger l8 carried by a spring blade l9 from the inner end of the suction box l4. Suction is applied to the tube I5 by a nozzle 20. The arms [5 with their associated suction grippers and preliminary sheet stops are adapted to be reciprocated longitudinally and to be elevated and lowered in relation to the layboard by means of any convenient mechanism indicated generally by the reference numeral 2| in Figure 1, the movement of the arms being in synchronism with the main cycle of operations of the machine.

The apparatus described above may be operated in the following manner. Suction is applied at the mouths it before the leading sheet has reached these mouths. The effect of this is to apply a brake to the travel of the sheet so that it does not become crowded up against the preliminary stops [8 but is smoothly arrested by the preliminary stops in a squared up position. The mechanism 2| then operates to forward the grippers I4, suction being maintained until the front edge of the sheet reaches and is arrested by the front lays 13 of the machine. At this point the suction is cut off or reduced so that the sheet is left at the front lays while the stops and grippers slide off the sheet. Thereafter the mechanism 2| operates to lift the combined suckers and preliminary stopsleaving the sheet clear to be taken into the press-and to return them to their initial position ready to engage the next sheet.

In an alternative method of operating the apparatus, the combined suckers and preliminary stops are arranged to be moving towards the press lays l3 at a lower speed than the sheets are advanced by the main conveyor. The leading sheet then overtakes the combined suckers and preliminary stops and is squared up" to these stops while moving to the press lays.

I claim:

In a sheet feeder a feed board, a sucker arm, a. sucker at the forward end thereof having a plurality of suction orifices longitudinally spaced apart in the direction of sheet travel over the feed board, means pivotally connected with the rear end of said arm for moving the sucker back. and forth in the direction of sheet travel and means for raising the sucker while a sheet is being withdrawn from the feed board, the sucker being arranged to rest on a sheet on the looard and with suction applied to the orifices" during its forward travel and a sheet stop arranged to i travel with the sucker and slightly ahead there -0f in the direction of sheet travel whereby the forward edge portion of a sheet admitted be tween the sucker and the board will be gradual- 1y slowed down by suction asthe forward edge of the sheet successively closes the suction orifices and by relatively slow forward movement of the sucker and the forward edge will be positively arrested and precisely positioned relatively to the sucker by engagement with the sheet stop.

HEADLEY TOWNSEND BACKHOUSE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 567,730 Wood Sept. 15, 1896 1,289,628 Breen et al Dec. 31, 1918 2,328,943 Backhouse Sept. '7, 1843

Images