US 3226108 A
Description (OCR text may contain errors)
Dec. 28, 1965 T. D. BISHOP 3,226,108
SUCTION FEED MECHANISM FOR CORRUGATED AND LIKE CARDBOARD Filed Oct. 29, 1962 2 Sheets-Sheet 1 fin w T. D. BISHQP Dec. 28, 1965 SUCTION FEED MECHANISM FOR CORRUGATED AND LIKE CARDBOARD Filed Oct. 29, 1962 2 Sheets-Sheet 2 United States Patent 3,226,108 SUCTION FEED MECHANISM FOR CORRUGATED AND LIKE CARDBOARD Thomas Desmond Bishop, Solihnll, England, assignor to The Deritend Engineering Company Limited, Birmingham, England, a British company Fiied Oct. 29, 1962, Ser. No. 233,663 Claims priority, application Great Britain, Nov. 11, 1961, 40,446/61 1 Claim. (Cl. 271--32) The present invention has relation to suction feed mechanism for corrugated and like cardboard. Suction mechanism has been proposed wherein a reciprocatory suction cup conveyed the lower board of a stack to feed rollers and such mechanism for example, that described in the United States Patent No. 2,331,533, issued October 12, 1943 to E. L. Bishop, was successful when dealing with a variety of cardboard of a solid nature. Corrugated cardboard today is used extensively for the manufacture of boxes and the like but its character diflfers from the solid section board inasmuch as it comprises a corrugated hollow inner section with outer facing paper or board. In a suction machine of the character disclosed in the aforesaid patent powerfully gripping solid feed rollers were employed with success and these securely held the cardboard blank and fed it to the machine for treatment such as slotting, creasing or the like, any suction remaining in the suction cup being readily overcome by the powerful grip of the feed rollers. Such powerful grip of the feed rollers is not now permissible as it destroys the nature of the corrugated board and in order to overcome this difhculty rubber covered rollers have been provided. These however were not sufficient to overcome any suction still left in the suction box and the present invention has for its object to so adapt the suction cup, its timing and its relation to feed rolls that the more delicate corrugated board is successfully fed from the lower part of the stack to the feed rollers and is successfully taken over by them without damage, it being understood that such a machine may feed several large corrugated blanks per second.
According to the present invention there is provided a suction feed mechanism for corrugated and like cardboard wherein the reciprocatory suction cup on its forward or feeding stroke firstly gathers speed or momentum to displace the lowermost blank towards the rollers and finally attains a speed equal or substantially equal to the peripheral speed of the feed rollers, this speed being maintained for a short period of time to enable the grip of the suction box to be substantially reduced so that when the suction box slOWs up it will not influence the blank during its continued passage into the treating machine, said box accordingly being carried by a hollow ram slidable within a stationary member, said hollow ram and said stationary member being ported to alternately connect with a suction source and the atmosphere, the porting being such that the suction in the suction box remains until the board is taken over by the feed rolls when that port connected to the atmosphere is opened and the suction port closed which releases the lower board from the suction cup and allows the feed rolls to take over.
In order that the invention may be clearly understood and readily carried into practice reference may be had to the accompanying explanatory drawings, in which:
FIGS. 1 and 2 illustrate in vertical sectional elevation suction feed mechanism in accordance with the present invention, FIG. 1 illustrating suction in operation and FIG. 2 suction cut smartly off the lowermost board having been taken over by the feed rolls. In these two figures the two ports connecting respectively to the suction and subsequently to the atmosphere are shown in a vertical position for the purpose of clarity whereas,
FIG. 3 is an isometric view showing the suction box with the ports in the ram and cylinders in correct horizontal or lateral setting,
FIG. 4 illustrates the feed rolls in elevation, and
FIG. 5 is a diagrammatic plan view of the suction box and its local ported slidable mounting.
In a convenient embodiment of the present invention there is provided a table a, a whereon the stacked pile of corrugated and like cardboard blanks b hereinafter referred to simply as blanks, are placed. The table a, a may operate on a forward pivot 0 so that its inclination can be varied and at the fore-part of the table there is provided a gate e against which the lower part of the stack b bears and beneath this gate the lower blank is drawn by means of a reciprocatory suction box 1. Immediately adjacent the gap beneath the gate are feed rollers g, g see FIG. 4, which are driven and the upper feed roller g may have a rubber or synthetic covering giving a high co-efiicient of friction, the lower roller may be similar or it may be longitudinally grooved as illustrated. Centrally the rollers are gapped at g g so that the nose of the suction box 1 can pass between them and it is to be appreciated that while this happens the blank which is considerably wider than the suction box is taken up by the feed rollers g, g In this invention a built up vacuum may be employed as in the case of that described in the foregoing US. Patent No. 2,331,533, or a steadily maintained vacuum may be employed and accordingly the lowermost blank is Seized by the suction box 1 and is fed forward beneath the gate 2 at a gradually increasing speed and this speed is timed so that its final velocity coincides with the peripheral velocity of the rollers g, g when the blank is brought into engagement therewith and this velocity is maintained for about /8") to allow time for the negative pressure to be returned to substantially atmospheric pressure in the suction box. Negative pressure is maintained in the suction box during the feed to the feed rollers but once the forward edge of the lowermost blank b has been successfully and completely engaged by the feed rollers the suction in the suction box is cut off and brought to atmospheric pressure as quickly as possible so that no hold is obtained on the blank other than that obtained by the feed rollers which feed it forward. This is effected by cutting off the suction and opening to atmosphere by the porting of the ram and its supporting bore as hereinafter more particularly described.
It is to be appreciated that it is impossible to reduce the suction in the suction box to atmospheric pressure instantaneously. It therefore takes a short period of time to transfer the grip from the suction box to the feed rollers, during this period of transfer it is essential for the suction box and the feed rollers to be travelling at substantially the same speed, otherwise the blank will slip in the feed rollers resulting in the board being (1) misaligned and/or (2) arriving at the treating machine at the incorrect time.
In order to reduce this period of time that is taken to bring the pressure in the suction box up to atmospheric, it is essential that the orifice I1 (FIG. 3) into the atmosphere (hereinafter more particularly referred to) is as close to the suction box 1 as practicable and also the rate at which the orifice I1 is opened is as great as possible. This rate has to increase as the velocity of the suction box increases and the port d in the ram accomplishes this. Furthermore it is advisable that the position at which the suction into the suction box 1 is cut off is as close to the suction box as possible.
Conveniently a box-like structure 11, ee particularly FIG. 3, is mounted beneath the table a wherein a hollow ram d is slidably mounted within a bore I1 and the forepart of the ram d is arranged to carry the suction box 1 in correct position in relation to the table a.
The ram is propelled forwardly and rearwardly by a lever (not shown) attached to its extremity and which is actuated by suitable cam and check cam mechanism to give it the correct speed and positive movement and when the ram is in a rearmost or withdrawn position (FIG. 1) a conduit I2 which registers with port 03 connects with the suction pump so that the suction box is subjected to a negative pressure. The forward speed of the suction box as previously intimated is increased until it reaches the peripheral speed of the rollers g, g when the port d in the conduit in the hollow ram d is completely disconnected from the suction pump and registers with an outlet 11 so that the suction box is rapidly subjected to atmospheric pressure to release the blank to be taken over by the correctly speeding feed rollers g, g. a is a plate attached to the rear part of the suction box 1 and slides on the flat top of the member 11 shown in FIG. 3. In order to ensure the cleanliness of the air a power driven rotary disc filter with brush may be employed. This disc filter may have a number of gauzes which are brought into register with the conduit and these gauzes are suitably brushed or blown or sucked clean when the disc is rotated. This prevents the passage of powder or dust along the conduit.
Mechanism for feeding corrugated cardboard blanks comprising, in combination, a support for holding a stack of blanks, a gate for preventing forward movement of blanks above the lowermost blank in the stack, a suction box for gripping by suction the underside of the lower- 30 most blank, means for moving the suction box forward from a starting position beneath the stack at a speed that increases gradually to a maximum value and remains at such maximum value for a finite period, a first valve which connects the suction box to a vacuum line to cause it to grip the lowermost blank while the suction box is moving forward at increasing speed, a pair of feed rolls which are driven continuously at a peripheral speed equal to the maximum linear speed of the suction box and which are so located as to engage the lowermost blank immediately after the suction box attains its maximum linear speed, a valve-operating member operatively connected to the suction box to close the first valve immediately after the feed rolls engage the lowermost blank, and a second "alve operatively connected to the suction box to admit atmospheric air to the suction box immediately after the feed rolls engage the lowermost blank, said second valve being effective to release the lowermost blank from the suction box while the suction box is still traveling at its maximum speed.
References Cited by the Examiner UNITED STATES PATENTS 1,162,658 11/1915 Schylander et al. 27132 X 2,331,533 10/1943 Bishop 271-32 2,827,290 3/1958 Dixon 2'7132 3,105,681 10/1963 Bishop et al 271-32 M. HENSON WOOD, JR, Primary Examiner.
ROBERT A. LEIGHEY, SAMUEL F. COLEMAN,
ROBERT B. REEVES, Examiners.