US1542739A - Press for molding plastic substances - Google Patents

Description

w-. H. sMl-rH 4 Filed June e, 192s s sheewsheet 1 PRSS FOR HOLDING PLASTIC SUBSTANCBS June 16, 1925.

June 16, 1925. 1,542,739

' w. H. SMITH PRESS FOR HOLDING PLASTICxSUBSTANCES Filed June 6, 1923 3 Sheets-Sheef 2 pag.2.

June 16, 1925.

W.- H. SMITH PRESS FOR MOLDING PLASTIC SUBSTANCES 3 Sheets-Sheet 3 Filed June 6, 1925 Patented June 16, 1925,

UNITEDv STATES PATENT OFFICE.

WILLIAM HERBERT SMITH, OF EAST MOLESEY, ENGLAND, ASSIGNOR T0 TRIANGULAR CONSTRUCTION COMPANY LIMITED, 0F EAST MOLESEY, ENGLAND.

IRESS FOR MOL'DING PLASTIC SUBSTANCES. v

Application filed June 6,

To @ZZ whom it may concern:

Be it known that I, VVILLTAM HERBERT SMITH, a British subject, residing at The Bungalow, Imber Court, East Molesey, in the county of Surrey, England, have invented, certain new and useful'lmprovements in Presses for Molding PlasticV Substances, of which the following is a specilicatiom This invention relates to presses for' molding plastic substances and is particularly applicable to presses for forming blocks or slabs of concrete and like substances'.

Ank object of the invention is to provide an improved press having a double toggle operating mechanism.

A further obj ect is to provide such a press wherein one toggleJ functions in applying the necessary pressure to the material in the mold and will hereinafter be referred to as the pressure toggle and the other toggle functions in stripping or ejecting the molded article from the mold and will'hereinafter be referred to as the ejection toggle,

' the movable links of both toggles. being connectedat different points to a common transmission member in operative connection with a plunger.

In the preferred form of the press the movable plunger is connected to a link, which will be termed the transmission lever which is pivotally connected at its far end to the movable link of the pressure toggle and at anintermediate point to'themovable link of thek ejection toggle.' f

The press will be described in a form suitable for hand operation but it is to be understood that power operated lmeans may be substituted for the hand levers described.

Although the invention is applicable to machines in which positive relative movement between pressure platev and mold is given at one end only, it is preferred to embody vit in a machine in which such relative movement is given at both ends of the mold.

Other objects and features of the invention will be understood from the following Y description of a preferred form of 'press and from the appended drawings, wherein Figr. 'l represents a side elevation of the machine, partly 1n sectiomthe various levers 1923. serial No; 643,739.

beingshown in their positions during filling of the mold.

Fig. 2 represents a front elevation of the machine partly in section.

Fig. 3 yis a diagrammatic view showing the various levers in their position at which the material in the mold is subjected to maximum compression.

Fig. 4 is a similar diagrammatic view at the end of the ejection movement.

The press is provided with a mold' A provided with a movable bottom plate B; this bottom plate is supported by a number of pressurey rods C carried bv a cross-head I) which is guided in the hollow standards E arranged at the sides of the machine. Two operating hand-levers are provided; one, the pressure lever F applies the pressure to the mold, and the other, the ejection lever Gr is employed for ejecting the molded block.

Each :of these hand levers is connected through atoggle linkage to a transmission lever Il, and to ensure smoothness of action it is preferred to provide this linkage and transmission lever mechanism on both sides of the machine. Y

, The pressure lever F is pivoted on a shaft j and an extension F1 thereof is connected by. a link J with pressure Goggles K one of which is carried by a fixed pivot K1 and the other of which is pivoted tothe end of the transmission lever H.

The ejection lever G is pivoted upon a shaft L which carries an arm M pivoted to n pivot P and the lower of which is pivoted v to the lever H by a pivot 7L.

A to pressure plate Q is carried by parallel mot on links R normally held in raised position by a spring S. The lower link R, carries a shackle provided with a bail T under which engages a hooked top` pressure rod U.

`The operation of the parts so far dee scribed may be summarized as follows Referring to Fig. l the mold is first filled with concrete or other material to be molded which is conveniently stored in a hopper Z. The top plate Q is then lowered and 1n so doing the hooked rod U snaps over the bail T under the action of a spring a. The ejection toggle being closed, the pivot /i acts as the ulcrum of the transmission lever H and as the pressure lever f is lowered pressureis applied through the toggles K to the pivot at the end of the transmission lever thus causing the cross-head D to rise and the bottom plate B positively to compress the material in the mold from the bottom thereof. The force applied at the topof the lever F is magnied three times; once by the lever itselt', then'Y by thel toggle Kand finally by the lever H, the pressure increasing as.thema-terial in the mold becomes more compacted.

Ars thetransmission lever .lvl moves downwards it exerts a heavy pull tol be `exerted on the rod` U which thus causes a heavy pressure tozbeapplied to the top pressure pla-te Q' which therefore exerts a positive compression et the material in the top of the mold. This positive relative movement between Vthe pressure plates and the mold at both ends thereof ensures homogeneity in the resulting block.

Figz' represents theposition ofthe levers at the point at which the toggles K, reach dead cen-tre andniaxiniium pressure is CX- verted onl the mold.4 Further depression of the lever F cause-s the toggles K to pass their cleadcentre andthus releases the pressure 'onl the mold thus removing the grip of the hooked rodU upon the bail T. In

Amed-i-ately after this release of pressure a cam Y on the shaft engages a roller upon a bell-crank lever lV connected by a rod Vengagingithe rod U, thus causing the latte-r to be pulled1 back-Wards clear of the bail T, whereupon the pressure plate Q rises `angler the action oi'the spring S.

The ejecting-lever G is nowf raised and in so doing it breaks the toggle O, and. the

pressure toggle remaining fixed in position just beyond dead centre shown in Fig'. Ll, the pivot 7L noiv Vfunction-sk asl the fulcrum ot the transmission lever H.. rlhe lever H thus moves further upcarrying with it the bottom plate B and ejreeting the molded block from the mold. VThe arrangement-ot the levers isV such that the maximmn ejecting pressure is exertedA on the bottom plate BA at the begin-ning of the ejection operation .Whenthe resistance to ejection has its.

maximum value.

Thein-achine is shown Witlrthe moldv designed for the manufaeture of hollow. blocks of triangular cross-section, Ylor the iormation ofthe apertures whereof cores c are employedandbraced front members f, Fig. 2, provide the Walls for the two shorter sides of the triangle.

tion, hollow or solid, may beiormed Within the width capacity of the machine, the

thickness of the blocks being varied by ad,

standards are closed at the topiby covers .fl fi' and the guides are therefore protected Yfrom concrete or like gritty n'iat'erial falling on to them duringv use of the machine. The trouble commonly experienced with bloeit machines due to'elogging oiL the guide sur- 'lfaees is therefore n-iinimixed.

I claim:

l. Tn a block molding press the combinationot amold` adapted to contain the4 material to be moldedatogglc mechanism adapted toapply pressure toL the material, a second toggle mechanism adapted to eject the compressed material trom the mold. and a transmission member connected at dilierent points to both saidI toggle mechanisms and ulcrumed about the .point at Awhich it is connected to the first While vthe second is operativi-3.

Q, In a bloeit molding pressH the combinaotamold adapted to. contain the material to be molded a toggle mechanism adapted to apply pressure tol the material, a second toggle-mechanism adapted to eject the compressed material romthe mold, and a transmission member connected at dill'erent points to both said toggle mechanisms and lulcrumed about the point at which itI is connected to the second while the first is operative.

3. In a block molding. press thecombination otv amold adaptedtocontain the material to be molded a, toggle mechanism adapted to apply pressure' to the material, a second togglemechanism adapted-to eject the compressedimaterial iromthe mold, and a vtransmission member connected atdilierent points to both .said toggle mechanisms and fulerumed, While either toggle is operative, about` the point. at which it is connected to the other.

t. In a block. moldingpress, the comliination of a mold adapted to contain the material to be molded, a toggle mechanism adapted toapply pressure tothe material, a second toggle mechanism adapted toreject the compressedniaterial from themold, a transmission member connected at different Vpoints. to both said toggle mechanisms and operative, a pressure plate at each end of themold and interconnecting mechanism causing the pressure plates to move in opposite directions relatively to the mold by the operation of the transmission lever.

5. In a block molding press, the combination of a mold adapted to contain the material to he molded, a toggle mechanism adapted to apply pressure to the material, a second toggle mechanism adapted to eject the compressed material vfrom the mold, a transmission lever through which the movement of the toggle levers is transmitted to a pressure plate at one end of the mold, a hooked tension rod adapted to transmit motion to the pressure plate at the other end of the mold, and means for disengaging said tension rod from the pressure plateal'ter the tension in the rod has been removed.

6. A press for molding blocks of ccncretel or other plastic materials, comprising a pressure plate operatively connected to a transmission lever, a pressure operating lever, toggle mechanism connecting said pressure operating lever With said transmission lever,

an ejection operating lever, a second toggle mechanism connecting said ejection operating lever with said transmission lever, and means for altering the :Fulcrum of said transmission lever according to whether a pressure movement or an ejection movement is required substantially as described.

7. A block molding press having a mold, a pair of pressure plates, a cross-head carrying one of said pressure plates, guiding means for said cross-head comprising hollou1 standards and means to cover the tops of said standards. c

8. A press for molding blocks of concrete or other plastic materials comprising a pressure plate operatively connected to a transmission lever, a pressure operating lever, toggle mechanism connecting said pressure operating lever With said transmission lever, an ejection operating lever, a second toggle mechanism connecting said ejection operating lever with said transmission lever and means for altering the fulcrum of said transmission lever according to Whether a pressure movement or an ejection movement is required substantially as described.

In testimony whereof I aiiix my signature.

. WILLIAM HERBERT SMITH.

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