US2756697A

US2756697A - Apparatus for moulding tablets of plastic material

Info

Publication number: US2756697A
Application number: US457110A
Authority: US
Inventors: Brook Leonard
Original assignee: Forgrove Machinery Co Ltd
Current assignee: Forgrove Machinery Co Ltd
Priority date: 1953-10-14
Filing date: 1954-09-20
Publication date: 1956-07-31
Anticipated expiration: 1973-07-31

Description

July 3 1, 1956 L BROOK 2,756,697

APPARATUS FOR MOULDING TABLETS QF PLASTIC MATERIAL Filed Sept. 20, 1954 4 Sheets-Sheet. 1

July 31, 1956 BROOK .2,756,697

APPARATUS FOR MOULDING TABLETS OF PLASTIC MATERIAL Filed Sept. 20, 1954 4 Sheets-'Sheet 2 Fay. 2.

L. BROOK July 31, 1956 APPARATUS FOR MOULDING TABLETS OF PLASTIC MATERIAL 4 Sheets-Sheet 3 Filed Sept. 2O 1954 .w u y l ,l i MAQ IN VENTO R HTTORNEYS July 31, 1956 A l.. BROOK 2,756,697

APPARATUS RoR MOULDTNG TABLETS oF PLASTIC MATERIAL Filed Sept. 20, 1954 4 Sheets-Sheet. 4

Lvve/vTa/e,

Ea/VARI) BRoQI APPARATUS FR MOULDING TABLETS: OF PLASTIC MATERIAL Leonard Brook, Leeds, England, assignor to The Forgrove Machinery Company Limited, Leeds, England, a company of Great Britain Application September 20, 1,954, Serial No. 457,110

Claims priority, application Great Britain ctober 14, 1953 t claims., (ci. 1in-s) rl`his invention relates to moulding apparatus of the type comprising a rotary die head, rotating on a horizontal axis, for moulding a rope of candy or like plastic stock into a string of formed tablets, each joined to the next by a thin web of stock, a conveyor below the die head for carrying the string of tablets away from the die head in a'substantially horizontal path and a guide for guiding the string of tablets from the diehead lto the conveyor. A machine of this type is described in British specification No. 640,440 dated July 19, 1950;

When production has been started onl a machine of this type it is desirable that the string of formed tablets should be maintained clear of the guide so that the conveyor may exercise a slight tugging action on the'string to assist in stripping the tablets from the die head. In the case of a belt conveyor, this may be achieved by running the belt at a slightly higher speed than vthe peripheral speed of the die head, with the result that when thestring of tablets has travelled a short distance on the belt it will be lifted clear of the guide. This will either cause the soft tablets constituting the string to be slightly elongated, or will cause the string to slip slightly on the belt. Either of these eiiects can be tolerated and the desired pull on the string of tablets will be achieved.

The present invention aims to employ, as the conveyor, a chain having pockets shaped to carry they tablets produced by the die head. With such a machine the guide must be so positioned as initially to guide the leading end of the string of sweets into the pockets of the` chain in the correct pitch, and it is not possible to cause the string of sweets to lift automatically from the guide by running the chain at a speed slightly higher than .that of the die head. On the contrary, it is `necessary that the die head and chain should run synchronously totensure correct feed of the tablets to the pockets of the chain.

The invention provides a moulding apparatus of the above type, in which the conveyor is a chain yhaving pockets shaped'to carry the tablets in the string and driven synchronously with the die head and comprisingmeans operable, without other than a momentary interruption of synchronous running of the die head and chain, to free the string from support by the guide so Y'that the string thereafter remains freely suspended between the die head and the chain.

Preferably I provide for a momentary retardation of the die head in relation to the chain. This may be elected by including in gearing driving the die head from the chain, or vice versa, a pair of meshing helical gears, one of which may be shifted axially to impart a momentary acceleration to the chain, or retardation to the die head, so causing the string to lift from the guide.

It will be appreciated that the guide can be arranged, as in the case of British specification No. 640,440, dated July 19, 1950, as a trip device for stopping the machine in the event of the string of tablets adhering to the die i head.

Aa guide 26 as shown in full lines in Fig. 1.

Two embodiments of the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which: v

Fig. l is a diagrammatic front elevation of the die head of the rst embodiment,

Fig. 2 is a corresponding side view of the gearing for driving the die head,

Fig. 3 is a side elevation, partly in section, of the mechanism for retarding the die head,

Fig. 4 is a corresponding plan view, and

Fig. 5 is a side elevation of the second embodiment.

Like reference numerals indicate like parts throughout the figures.

The moulding apparatus shown' in Figl is of generally similar construction to that described in British specification No. 406,220, dated February 22, 1934. The die head comprises an endless train of moulds constituted by pockets 1d in a moulding wheel 11, mounted on a hori- Zontal shaft 12, and a series of mould aps 13. The shaft 12 of the moulding wheel 11 is driven from a drive shaft 14, driven by an electric motor (not shown) through the agency of a pair of

helical gears

20, 21 and a pair of

spur gears

22, 23. The mould flaps 13 are pivoted on a wheel or chain (not shown) driven synchronously with the shaft12.

Normally the flaps 13 occupy the position shown at the left hand side of Fig. 1. As they approach the moulding wheel they are moved inwardly by a cam 15 and as they pass over the moulding wheel they are held down by a cam 16, as shown. The aps 13 thus cooperate Ywith the 'moulding cavities 10 to mould the rope 17 of boiled sugar or like stock which is fed into the machine. After the flaps 13 leave the cam 16 they are moved outwardly again by a member 18. The rope 17 of sugar is thus moulded into a string 19 of tablets, each joined to the next by a thin web of stock, which breaks easily when the sugar has cooled. The apparatus may include cams for causing inward movement of lateral dies to mould or emboss the ends of the tablets as described in British specification No. 406,220, dated February 22, 1934.

The string 19 of tablets is delivered in a downward direction fromfthe die head to the upper horizontal run of a conveyorfchain 24, passing over sprockets, not shown, one of which is driven from the drive shaft 14. The chain 24 has pockets 25 shaped to carry the tablets in the string 19.

Initially the tablets are guided on to the chain 24 by The string of tablets can, however, be lifted clear of the guide 26, and caused to assume the position shown in chain dotted lines in Fig. 1,'by1imparting axial movement to the helical gear-r21 as will now be described. The helical gear 21 is splined to the shaft 27 supporting it and is formed with an extension collar 23 engaged'by a. fork 29.

When the fork 29 is shifted from'the full line position of Fig. 2 to the chain dotted'position, the die head will receive a slight anti-clockwiserotationdue'to the helix angle ofthek teeth on the `gears 20,121. As the'die head is rotating in a clockwise direction,l it is accordingly retarded momentarily in relation to the conveyor chain, thus causing the string of tablets to lift from the guide 26.

As shown in Figs. 3 and 4, the fork 29 is carried by a bracket 30 fitted to the lower end of a spindle 31 mounted to rotate in a bush 32 secured to the machine framework. Fixed to the upper end of the spindle 31 is a cap 33, to which is pivoted at 34 a manually operable lever 35. The helical gear 21 is shown in Figs. 3 and 4 in the position shown in full lines in Fig. 2, i. e. the position it occupies at the start of a run.v The lever 35 then occupies the position shown in full lines in Figs. 3 and 4,

:in: which it is. held gby.engagement of a dete'nt 36 on'the lever with a notch 37 in the sleeve 32. When it is desired to shift the helical gear 21 to the position shown in chain dotted lines in Fig, 2, therlever 35 is swung anticlockwise l(as 4seenj-in Fig. 3)..aboutits: pivot 34%againstthe actionofy a spring 38,- thereby disengaging 'thewdetent' y36 from the notch 37. This freesvthespindle for rotation by the; lever 35-in an anticlockwise direction as seen in Fig. 4 to shift the helical gear 21 axially to 'the extent .requiredto retard the die'headl and cause the string 19 of tablets to lift from the guide 26 (Fig. l). The lever 35 is retained in itsvshiftedV .position by engagement of the detent 36 with'another notch in the sleeve 32.

It will beappreciatedthat, if fdesired, the string of tablets could be causedto lift from-@the ,chain byl imparting a momentaryacceleration.to the chain. ln'this case the arrangement so far described is modified as indicated in Fig. by applyingithe, drive from the electric-motor through azsprocket 113-totheshaft 112 of-the 'die-head .andshiftingethe helicalgear 21 zas described above 'in the direction of the arrow"A to impart a forward movement to the gearand therefore' amomentary acceleration to the chain'whichis ,driven from the shaft 114 by a sprocket 115.

In each of theillustratedembodiments an increase .in tension is Yapplied-to theistring 19 of tabletsfto cause it tolift from the guide `26 as the result of the momentary .variation in the-relative speedsof movement of the die head and the chain caused by the shifting of the helical :gear 21.

The. arrangement -illustrated isi advantageous because it is desirable that the, guide 26 should be associated, as .describedin Britishwspecification No. 640,440, dated July 19, 1950, withaztrip mechanism for stopping `the machine inthe event of. the tablets sticking in `the pockets 10.of.the Vmoulding wheel 1 1, thetrip mechanism being actuated in this event bypivotal movement of the guide.

What I claimas'my invention Vand desire to secure by Letters Patentis:

l.V Inl a machine for moulding ,tablets from afrope of plastic stock, in combination, a-diehead Vrotatable `on` a Vhorizontal axis andformed'with-mould cavities, means coacting withrsaid Adie-headfto ymould the ropeinto a string of tabletsf each joinedtoits--neig'hbors by a thin web of stock, a chain conveyor extending in a substantially. horizontal `pathbelow theudie head, driving mechanism for drivingsaidchainand said diezhead synchronously, said'chainhaving pockets spaced along its length and-shapedto receiveand carry the tablets: inthe str-ing, aguide, inclined downwardly from the open-sides: of the mould cavities in the die head to the open sides of the .pockets ofV the chain,v which :guide is :operative when .the machine `is started-to-'guide the string of tablets into the pockets ofthe chain; and means` operable vwhile the machine is running toadjust-said driving mechanism to create a momentary varia-tionfin'theV relative speeds 'of movement of :the die head and the chain andther'ebyfto -elfectmomentary lacceleration ofthe chain in relation to the die head.

f 2. In a machine for-moulding-tablets from a rope 'of .fplastic stock, in combination, a die head-rotatable on a Ahorizontal. iaxisandi zformed l with mouldy cavities, means coacting -with saidfdeyhead ,to-:mould therope intofa string of 'tablets Veach joined to its neighbors by a'thin web of stock, a chain conveyor extending in a substantially horizontal path below the die head, driving mechanism for driving said chain and said die head synchronously, said chain having pockets spaced along its length shaped to receive and carry the tablets in the string, a guide, inclined downwardly from the open sides of the mould cavities in the die head to' the open sidesY of the pockets in the chain, which guide is operative when the -machine is started toguide the string .of tablets intothe -pockets of= the chain, and means operable while the machine is running to adjust said driving mechanism to vary the `relative speeds of movementl of the die head and the chain and thereby to effect momentary retardation of the die head in relation to the chain.

3. In a machineforfmoulding tablets from a rope of plastic stock, incornbination, a die head rotatable on a horizontal axis and formed with mould cavities, means cooperating with the die head to mould the rope into a string of tablets each joined to its neighbors by a thin web of stock,- a chain conveyor extending in a substantially horizontal path below the die head, said chain having pockets spaced along its length and shaped to receive and carry the tablets in the string, means for driving the chain,

' gearing driving said die head from said chain and including a pair of meshing helical gears, a guide, inclined downwardly from-the open sides of the mould cavities in the die head tothe open sides of the pockets of the chain, which guide is operative when the machine is started to guide the string of tablets into the pockets-of the chain, and manually operable'means for shifting one of said .gears axially in relation to the other gear and thereby to effect momentaryretardation of the die head in relation to the chain.

4.v In a machine for moulding tablets from a rope of fplastic'stock, incombination, a die head rotatable on a Lhorizontal axis and formed with mould cavities, means c'oacting withr said die head to mould the rope into a string of tablets each joined to its neighbors by a thin web "of stock, a chain conveyor extending in a substantially horizontal path below the die head, driving 'mechanism for driving said chain and said die head synchronously, said chain having pockets spaced along its 'length and`shaped toreceive and carry the tablets in the string, a'guide, inclined downwardly from the open sides `ofthe mould cavities in the die head to the open sides of the'pockets of the chain, which guide is operative when 'Lthelmachine'is'started to guide the string of tablets into Lthe pocketsv of the chain, and means operable while the machine is running-to adjustsaid driving mechanism to create a momentary increase in tension in the string of *tabletsfthereby causing said string of tablets to lift from said, fguide.

References Cited in the le of this patent UNITED STATES PATENTS 1,442,119 Brach Ian.v 16, 1923 1,753,834 Ponisch Apr. 8, 1930 'FOREIGN PATENTS :406,220 GreatBritain Feb. 22, 1934 640,440 .Great Britain Iuly 19, 1950 648,488 VFrance Aug. 14, 1928