US2750875A

US2750875A - Means for discharging wafer making machines

Info

Publication number: US2750875A
Application number: US249600A
Authority: US
Inventors: Finlayson John
Original assignee: Baker Perkins Ltd
Current assignee: Baker Perkins Ltd
Priority date: 1951-08-03
Filing date: 1951-10-03
Publication date: 1956-06-19
Anticipated expiration: 1973-06-19

Description

June 19, 1956 J FINLAYSQN 2,750,875

MEANS FOR DISCHARGING WAFER MAKING MACHINES Filed 0ct.'3, 1951 2 Sheets-Sheet 1 I Z 121) (ELZ'Z/"bOl e7. Fuzz 62576 012/ W722 M June 19, 1956 ,.F] 1 Y 2,759,875

MEANS FOR DISCHARGING WAFER MAKING MACHINES Filed Oct. 3, 1951 2 Sheets-Sheet 2 JFLJZZQ/y QLQ 1 I 2,750,875 MEANS FOR DISCHARGIN G WAFER MAKING MACHINES John Finlayson, London, England, assignor to Baker Perkins Limited, Peterborough, England, and McVitie & Price Limited, Edinburgh, Scotland Application October 3, 1951, Serial No. 249,600 Claims priority, application Great Britain August 3, 1951 2 Claims. (Cl. 99-373) This invention relates to machines for making wafers and like articles of the type in which upper and lower paired mould plates or tongs (hereinafter referred to as tongs) are connected in an endless chain and moved in a path which includes passage through an oven, each upper tong being lowered and clamped on to its associated lower tong, after the latter has been charged with wafer batter at a charging station, prior to entering the oven, and being unclamped and raised from the lower tong (after passage through the oven) as the tongs re-approach the charging station whereby the cooked wafer is dischargeable from the opened tongs by gravity after the wafer has been freed or loosened from the lower tong mould surface.

Heretofore, in order to free the cooked wafer from the lower tong, it has been necessary for an operator manually to loosen or initially displace the wafers, for example with a spatula. This procedure involves the use of an extra operator and has the additional disadvantage that a proportion of otherwise satisfactory wafers are damaged.

The object of the present invention is to provide means for effecting the freeing of the cooked wafers from the tongs automatically as the tongs are sufiiciently opened, so that the wafer can be discharged by gravity.

The invention consists in a wafer making machine of the type indicated wherein air jet means are provided and disposed so as to direct localised jets of compressed air at an angle to the plane of the wafer such that they impinge against the approaching leading edge only of each lower wafer tong at its junction with the wafer as its associated upper tong is lifted and While the wafer is still inclined at a sufficiently steep angle to drop by gravity from the lower tong when freed by the air jet.

In a preferred form of the invention according to the preceding paragraph, the air jet means comprise a nozzle located to one side of the path of the tongs and directed to impinge the air jet in the lower tongs leading edge substantially midway thereof and at an angle thereto as viewed in plan, a satisfactory angle being about 30.

It has been previously proposed to employ compressed air jet means for assisting the discharge of wafers from wafer machines of the type indicated by providing a plurality of spaced air jet nozzles located to direct air jets in the plane of the wafer and to cause them to impinge along each lateral side of the wafer tong and along its trailing edge whereby the wafer is lifted from the mould and made to vibrate. In practice this arrangement failed since the wafer did not in fact lift in a satisfactory manner and moreover the extended air jet means (located on three sides of the wafer mould) caused each mould subjected thereto to be cooled to an undesirable degree.

The air jet means according to the present invention is arranged to act on one edge only of the wafer (i. e. the leading edge), to attack the wafer from below its plane so that the wafer is assisted in lifting from the lower tong and is localised as to its impingement on the wafer tong so that its cooling effect is reduced to a minimum.

The air jet nozzle according to the invention may be of any suitable form to produce a narrow jet of air for the purposes described above and is located conveniently tonne side of the path of the moving tongs. In order to' ensure that the loosened Water (which is caused to nited tates Patent Patented June 19, 1956 flutter by the air jet) falls by gravity without slewing or turning a guide plate may be located alongside the path of the tongs on the same side as the air jet nozzle, so that if a wafer tends to slew it is guided back into a straightened alignment.

In case the air jet fails to loosen and lift a wafer, a lifting blade may be provided on the fixed structure of the machine and located so that its end projects between the upper and lower tongs as they open, the blade just clearing the leading and trailing edges of the lower tong but being adapted to engage the leading edge corner of the wafer to hold the same and cause it to be loosened as the lower tong continues its movement. The blade also assists the normal working of the air jet means by preventing a loosened, fluttering wafer from dropping back into engagement with the moulded surface of the lower tong.

As an alternative to a single air jet being provided as described above, additional air jet means may be provided to cause air jets to impinge locally on the leading edge of the lower wafer tong as the tongs open. For example a second air jet nozzle may be provided, duplicating the one already described, on the other side of the path of the tongs and arranged to cause an air jet to impinge on the lower tong edge at or about the same point or area as the other jet.

in the accompanying drawings:

Figure 1 is a side elevation of one end of a known wafer machine of the type indicated with the batter delivery nozzle and associated known parts omitted to show more clearly the air jet means according to the present invention.

Figure 2 is a plan view of part of the machine shown in Figure l, and

Figures 3 to 6 are diagrams showing the relative positions of the air jet means and the wafer tongs as they begin to open, Figures 3 and 6 being side elevations and Figures 4 and 5 plan views.

In carrying the invention into effect according to one mode, by way of example, a wafer making machine of known character (to which no claim is made per se) consists in an endless chain 1 of wafer moulds each comprising an upper tong 2 and lower tong 3, which may be provided in known manner with embossed patterns (not shown) and are adapted to mould and cook a wafer or other article therebetween during their movement around a closed path 4 which passes through a heate oven space 5.

The lower tong 3 is charged with batter at a charging station A by means of batter nozzles carried on a displaceable arm in well known manner, the batter nozzles and arm being omitted from the drawings for clarity. The batter arm is supplied with batter through pipe 6, which can be rotated by a rack 7 on actuation by cam lever 8 and cam 9 to displace the batter nozzles into their operative position at charging station A. The supply of batter through a supply pipe 10 is governed by an intermittently operating pump 11 driven from the wheel 12 which carries the previously mentioned cam 9 whereby the batter supply operations are synchronised.

Charging at station A takes place while the

tongs

2 and 3 are moving (in the direction of the arrow B), the upper tong 2 being therefore guided downward to engage the lower tong 3 by the engagement of a boss 13 with a pair of rails or horns 14, described hereafter with reference to the opening of the tongs. When the tongs are closed, the upper tong 2 is locked to the lower tong 3 by the engagement of a locking member 15 with a catch 16 on the lower tong structure, the locking being maintained until the tongs are ready to be opened as described hereafter. The locking mechanism is of known character and forms no part of the present invention.

From the charging station A the closed tongs are moved in direction B around the closed circuit 4, passing through the oven in which the wafer is cooked. As the tongs approach the charging station A once again, they reach a discharge station C at which the tongs are unlocked and caused to separate by re-engagement of the boss 13 with the rails or horns 14 which are arranged to lift the upper tong 2 clear of the lower tong 3 to give access to the cooked wafer for removal, which heretofore has been loosened by hanc. so as to slide by gravity from between the tongs and down a chute 17.

The foregoing description with reference to Figures 1 and 2 of the drawings has been concerned with the con struetion and operation of the known machine to which the present invention is applied. in order to make the discharge of cooked wafers from the tongs as they open fully automatic so that manual loosening of the wafer from the lower tong 3 is obviated, air jet means are provided and will now be described.

Secured to the frame structure 18 of the machine is an air nozzle 19 located to one side of the path of the moving tongs and aligned so as to direct a jet 20 of compressed air against the leading edge 21 of the lower tong 3 at the junction of the wafer therewith and at about its mid point. The angle y made by the air jet 2% with the leading edge 21 (see Figure 4) is conveniently between and preferably about 30 and the angle x between the air jet 20 and the plane 22 of the lower tong 3 at the moment of operation of the jet may be between 120 and 165, preferably about 150 (see Figure 3).

The air nozzle 19 is connected to a convenient source of compressed air by

pipes

23 and 24 and, in order to provide for timing of the air jet and its cut-off, a

timing valve 25 is located between

pipes

23 and 24. 5

The valve 25 is actuated by a lever 26 pivoted at 27 to the machine frame and carrying at its other end a cam-following roller 28 arranged to co-operate with a cam surface 29 on the wheel 12, which is driven through bevel-gear drive 30 from a shaft 31 in step with the movement of the endless chain of wafer tongs. By this arrangement, the jet 26 of compressed air is directed on to the leading edge 21 of the lower tong 3 just as the tongs open and is cut off, until the next pair of tongs arrive, after a short interval, e. g. equal to approxiinately one third of a revolution of the wheel 12 which is equivalent to one third of a pitch movement of the tongs. The duration of the air jet is suflicient to loosen the wafer from the mould surface of the lower tong 3 and cause the wafer to flutter or vibrate which assists the discharge of the wafer by gravity down a chute 17.

In order to prevent a loosened wafer from losing alignment with the chute 17 should the wafer tend to slow as it lifts from or leaves the tongs, a guide plate 32 is mounted as by a bracket 33 of the machine frame to guide the wafers into alignment with the chute 17. The guide plate 32 is located so that it is just cleared by the tongs as they open and opposite the opening mouth of the tongs.

Further in case of failure of the air jet 20 to loosen a wafer, a blade 34 is also mounted on the machine frame and adjusted as to position so that it is just cleared by the leading edge 21 of the lower tong 3 (and therefore also by the trailing edge). The blade 34 engages the edge of the wafer and holds it while the tongs continue their movement, thus loosening the wafer. The blade 34 also serves to prevent a wafer loosened by the air jet 20 from falling or being blown back into engagement with the mould face of the lower tong 3 by entering under the lifted wafter as it vibrates.

In an alternative arrangement to that described above, air jet means may be located on each side of the path of travel of the tongs, e. g. as shown in Figure 5, wherein in addition to the nozzle 19 a second nozzle 19a is similarly located on the other side of the machine frame vention may be applied to any wafer machine of the type indicated. Thus, for example, where the tongs open at an earlier point on their path of travel, see Figure 6, the nozzle 1912 may be located so as to provide the best angle of attack for the jet 2% on the leading edge 21 of the lower tong 3. In other words the horizontal disposition of the nozzle 19 shown in Figures 1 and 3 is not an essential, its location being dependent on the point of opening of the tongs and other features of the design of the machine to which the invention is to be applied.

1 claim:

'1. In a wafer making machine of the type including a plurality of pairs of tongs movable in a predetermined path, including a component of movement in which the tongs are at an angle to the horizontal and said pairs of tongs each comprising an upper and a lower tong having leading edges, a discharge station past which the tongs move while in the angular relationship to the horizontal, means adjacent the discharge station for opening the tongs, and means for directing at least one jet of compressed air toward the oncoming tongs including a nozzle mounted at one side of the path of travel of the tongs so that the tongs can pass the same, said nozzle being directed at an angle of between 25 and 45 with. respect to the leading edge of the lower tong and directed toward the path of movement of the lower tongs along a line that intersects the path of movement of the lower tongs approximately midway of the leading edge thereof so that air impinges against the leading edge only of the lower tong at its junction with the wafer at approxi mately the midpoint of the leading edge of the lower tong as the tongs are being opened whereby the angular relationship of the lower tong with respect to the horizontal permits the wafer to discharge by gravity when freed from adherence to the lower tong by the air.

2. In a wafer making machine as defined in and by claim 1 in which the air directing means include two nozzles located on opposite sides of the path of movement of the tongs and positioned at opposite sides of the path of travel of the tongs such that the tongs can pass between said nozzles and respectively directed toward the path of movement of the tongs at an angle of between 25 and 45 with respect to the leading edge of the lower tongs and directed toward the path of movement of the tongs along a line that intersects the path of movement approximately midway of the leading edge of the lower tongs so that two air jets impinge against the approximate midpoint of leading edge of the lower tong from two directions.

References Cited in the file of this patent UNITED STATES PATENTS 797,604 Perky Aug. 22, 1905 1,196,147 Prescott Aug. 29, 1916 1,278,659 Howe Sept. 10, 1918 1,283,888 Pope Nov. 5, 1918 1,484,204 Betz Feb. 19, 19.24 1,808,997 Schroeder et a1. June 9, 1931 2,051,303 Leichter Aug. 18, 1936 2,302,499 Lacson Nov. 17, 1942 2,349,583 Tatosian May 23, 1944 FOREIGN PATENTS 269,551 Great Britain Aug. 25, .1927