CA1194724A - Manual extruder for shaping pasta or similar products - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A manually operable extrusion press, especially one for producing pasta from a mass of dough, comprises a cylinder with a piston whose piston rod is embraced by flexible prongs of an operating lever that are pivoted to the top of the cylinder opposite a bottom nozzle provided with one or more shaping apertures. The sides of the piston rod facing the prongs have serrations coacting with driving pawls disposed on the inner prong surfaces which are outwardly yieldable during an upswing and engage the serrations on a downswing of the lever, the serrations being also engageable by retaining pawls on the cylinder serving as backstops. A 90° rotation of the piston rod about its axis confronts both pairs of pawls with flat rod surfaces to enable free upward or downward motion of the piston. The entire assembly preferably consists of plastic material such as glass-fiber-reinforced polyamide.

Description

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MANVAL EXTRUDER FOR SHAPING PASTA OR
SIMILAR PRODUCTS
The present invention relates ~o a manually operable press for the extruslon of dough or a similar pasty mass, e.g.
a cream, through one or more nozzle apertures serving to produce shaped objects.
Devices of this kind, particularly ki~chen utensils used for making pasta, include a cylinder which usually is centered on a more or less vertical axis and contains a piston rod designed to expel the contained dough through an extruslon nozzle disposed at one end -- generally the lower one -- of that cylinder. A piston rod projects from the opposite cylinder end and is intermittently displaceable, with the aid of an operating lever articulated to the cylinder near that end, toward the noz~le end thereof. The lever, which is limitedly swingable in an axial plane of the cylinder, coacts with the ~od through a one-way coupling so as to advance same on a forward swing (e.g.
downward) and to release that rod on a reverse swing whereby the dough is progressively converted into the type of shaped products known as pasta. The one-way coupling may comprise a thrust member in the form of a pawl pivoted on ox resiliently connected with the lever for drivingly engaging a sawtooth-shaped serration on a longitudinal surface of the piston rod; see, for example, German patents Nos. 958,011 and 2,704,432 (the latter being owned by the assignee of this present applica~ion). 'rhe first of these ~erman patents also teaches the provision of a second serration on an opposite longitudinal surface of the piston rod, these two serrations being of different pitch and being alternatively juxtaposable with the driwing pawl in order to let the user select a larger or a smaller advance of the 7~

piston on a given forward swing of the lever. Turning the rod through 90 confronts that pawl with a smooth surface so as to enable ~he unhindered manual retraction of the piston.
Another type of one~way coupling, described in German printed specification No. 11 40 525 published 6 December 1962, discloses a one-way coupling in the form of an apertuxed plate which, upon an upswing sf the operating lever against a ixed stop acting as a fulcrum, is tiltable into an inclined position in which the smooth piston rod is gripped between opposite edge lQ of the plate aperture so as to execute a downward step. A
similarly tiltable spring-loaded plate serves as a backstop.
The frictional clamping of the rod by this kind of coupling enables only limited pressure to be exerted upon the piston head unless the applied force is so laxge that, with the aper-~ured plate harder than the rod, the latter is notched by the gripping action.
Even with the positively acting pawl-type coupling described above, the known constructions require operating levers of considerable length in order to afford a suitable mechanical advantage in advancing the piston. This is due to the fact that, with the pivotal axis of the lever located at the far side of the piston rod as seen from the free lever end, the load arm measured between that pivotal axis and the junction of the driving pawl with the lever is relatively large and, as shown in German Patent No. 958,011, may be about equal to the cylinder radius. The operating lever and other parts of the mechanism must therefore be able to sustain and transmit the considerable force which the user is required to apply.
In the past, therefore, the devices here considered were 3 a generally made of metal.

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An object of this disclosure is to provide an improved extrusion press of this character which, thanks to a greater mechanical advantage of its operating lever and a more effective one-way coupling thereof with the associated piston rod, is more compact and efficient than conventional models and can thus be constructed more economically, at least for the most part, from plastic material rather than metal.
An extrusion press here described comprises the usual piston cylinder with a shaping nozzle at one end and a mounting member traversed by the piston rod at its opposite end, this piston rod passing between branches of an extremity of an operating lever articulated to the mounting member for swinging about a pivotal axis which is skew to the cylinder axis.
Pursuant to the presen~ improvement, the piston rod has two diame~rically opposite longitudinal peripheral zones provided with respective serrations of generally sawtooth-shaped profile and identical pitch, with steep rear flanks of the sawteeth facing away from the piston head reciprocable inside the cylinder. The two branches of the pivoted lever extremity have inner surfaces which, in a working position of the piston rod, respectively confront the two serrated zones and are provided with respPctive driving pawls whose front edges are engageable with the rear flanks of their sawteeth. The mounting member is further provided with detent means resiliently engageable with the serrations in the working position of the piston rod for back~stopping same upon an advance thereof by the driving pawls, the piston rod being rotatable into an îdle position in which the serrations are disaligned from the driving pawls as well as from the detent means.

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Thanks to their lateral positioning with re~erence to the swing plane of the operating lever, the driving pawls are separated only by a fraction of the cylinder radius from the pivotal axis whose distance from the free lever end exceeds only slightly the length of the moment arm defined by the separation of that free end from the points of attachment of the driving pawls. This provides a considerably greater mechanical advantage in comparison with the known constructions referred to above. The duplication of the driving pawls on opposi~e sides of the piston rod, moreover, doubles the pressure that can be transmitted by a single pawl BO that the pawls, the piston rod and the lever -- as well as preferably all other major parts of the device -- can be conveniently molded from plastic material. Particularly suitable for this purpose is a polyamide (nylon), reinforced with glass fibers where necessary.
The replacement of metal by a plastic material also eliminates the risk of corrosion, this being especially important in the case of a kitchen utensil coming into con-~act not only with food-stuffs but also with water and detergents.
The driving pawls, of course, must be retractable from the associated serrations in the course of a reverse swing of ~he operating leverO When the lever consists of a polymeric material of suitable elasticity, the pawls could simply be designed as resilient tongues unitary with the branches support-ing them. They could also be inherently inelastic but yieldably urged toward the piston rod by biasing springs anchored to the supporting lever branches. A simpler and sturdier arrangement, however, utilizes branches that are themselves sufficiently elastic to yield outwarcl together with the driving pawls mounted thereon. For this purpose I prefer to design the rod-embracing 47~4 lever extremity as a bifurcation whose prongs constitute the above-discussed branches and are pivoted to adjoining lateral walls of the mounting member which straddles these prongs with clearance enabling their elastic deformation on the reverse swing of the lever.
In an advantageous embodiment particularly described hereinafter, the pawls are fulcrumed on these prongs for swivel-ing about a common axis which is parallel to the swing axis of the lever and transverse to the cylinder axis. Instead of merely connecting the pawls with the prongs by simple pivot pins, pre-ferably they are provided with rear edges that are curved about their common axis and are contacted by correspondingly curved overhanging ledges of the prongs so that the thrust exerted upon the pawls on their driving engagement with the sawtooth flan~s is absorbed mainly by these ledges rather than by the relatively fragile pins. The thrust-absorbing overhanging ledges may form end walls of pockets of the prongs that are open toward the piston head, the driving pawls then having shanks which are received in the pockets and include an obtuse angle with heels terminating in the aforementione,d front edges. Pivot pins, whose main purpose is to withdraw the pawls from the serrations on the reverse swing, can then traverse the pockets 90 as to be supported at both ends instead of being merely cantilevered on the respective prongs.
Pursuant to another feature, an elastic ring constitut-ing the detent means lies in a plane transverse to the cylinder axis and has incisions forming two pairs of radially deflectable strlps which are separated by a small gap on opposite sides of a plane of symmetry bisecting the driving pawls. The ring may be braced against axial deformation by an internal annular shoulder ~ ~72~L
of the mounting member which preferably comprises a sleeve threadedly secured to the adjoining cylinder end; thus, the detent ring can be clamped between that cylinder end and the shoulder for easy disassembly when ~he device is to be cleaned.
Specific embodiments of the invention will now be described with reference to the accompanying drawings in which;
Figure 1 is a perspective view (parts broken away) of an extrustion press embodying the invention;
Figure 2 is a fragmentary longitudinal sectional view of the device of Figure 1, taken substantially on the line II -II thereof and drawn to a larger scale;
Figure 3 is a top view of the assembly of Figure 2, taken on the line III - III thereof;
Figure 4 is a cross-sectional view taken on the line IV - IV of Figure 3 and drawn to a still larger scale;
Figure 5 is a fragmentary sectional view generally taken on the line V - V of Figure 4;
Figure 6 is a bottom view of a detent ring/ drawn to the scale of Figure 2; and Figure 7 is a ~xaymentary sectional view si.milar to part of Figure ~ but illustrating a modification.
The device 10 shown in Figures 1 - 3 is a kitchen utensil designed for making pasta, comprising a cylinder 11 centered on an upright axis L (see Figure 2) and provided at its lower end with a detachable extrusion nozzle lla having an end disk llb with several shaping apertures llc. The upper end of cylinder 11 is partly closed by an inner annular shoulder 12a of a mounting sleeve 12 which, as see in Figure 2, is removably screwed onto the cylinder by threads 16; an upward extension 17 of sleeve 12 forms a socket which is open at one side to give L7~4 p~ssage to an operating lever 18 having a bifurcate extremity with two prongs 23 received with clearance in that socket.
Pronys ~3 spacedly straddle a piston rod 13 whose upper end is provided with a handle 13a and whose lower end carries a piston head 13b reciprocable within cylinder 11.
Piston rod 13, which like all other parts o device 10 consists of plastic material such as glass-fiber-reinforced polyamide, is tubular and provided on two diametrically opposite longitudinal peripheral zones with serrations 15 which are defined by sawteeth 14 of identical pitch. Two other diametri-cally opposite longitudinal zones 55 o~ rod 13 are completely flat. In the working position illustrated in Figures 1 ~ 3, the serrated zones respectively confront the prongs 23 of lever 18 which are articulated to socket 17 by a pair of aligned studs 20 centered on a pivotal axis 19 and provided with outer heads 20a, the inner ends of these studs being received in bearing mounts 21 rising from shoulder 12a as more fully described here-inafter with reference to Figure 5. Axis 19, it will be noted, lies just beyond piston rod 13 as seen from the free right-hand end of lever 18.
Prongs 23 are separated from each other by a narrow gap on opposite sides of a vertical plane 26 which includes the axis L of cylinder 11 and is perpendicular to pivotal axis 19.
Another axial plane 27, perpendicular to plane 26, contains --in two limiting positions of lever 18 -- a common axis 35 of two pivot pins 33 illustrated in Figures 4 and 5. Fulcrumed on each of these pivot pins 33 is a driving pawl 25 which, in the lever positions referred to, is bisected by plane 27 and is of generally L-shaped configuration, with a rising shank 28 received in a downwardly open pocket 32 of the respective prony 23 and , . \ .

7f~il with a heel 29 which includes an obtuse angle with shank 28 and terminates in a horizontal front edge 39. That front edge, whose wîdth substantially equals that of a steep rear flank 40 of each sawtooth 14, bears upon such rear flank in the hori-zontal position of lever 18 - shown in full lines in Figure 2 -which represents the limit of its forward swing.
Heel 29 of pawl 25 has an angular profile defined by two flat faces converging in front edge 39, these faces coming to lie against the rear flank 40 of one sawtooth and a less steep front flank 56 of an adjoining sawtooth in the driving position of Figure 4 so as to fill virtually completely the gap between two sawteeth 14. This wide-area engagement insures an optimum transmission of the lever pressure to piston rod 13 whose opposi~e serrations 15 coact simultaneously with the asso-ciated pawls 25. The backward thrust thus exerted upon khe two driving pawls is absorbed for the most part by an end wall 45 of each pocket 32, shown in Figure 5, which is curved about the common axis 35 of pivot pins 33 and is in all-around contact with a correspondingly curved rear edge 43 of shank 28.

Pivot pins 33, traversing the pockets 32 while being anchored in outer walls 30 and inner walls 31 thereof, are not particularly stressed by the driving force exerted during the forward swing but help extract the heels 29 of theix pawls 25 from the engaged serrations when the lever 18 is swung upward into its retracted position illustrated in phantom lines in Figure 2. In the midposition of that lever, separated by an angle w of about 11 from each of these two limiting positions, pins 33 lie on a common radial (i.e. horizontal) plane 37 with pivotal axis 19; thus, the heels 29 of pawls 25 are precisely aligned with sawteeth 14 in each of these two limiting positions '~

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of lever 18 and are only slightly offset therefrom in its mid-position as their axis 35 travels along a small arc 38 centered on axis 19. The level difference 36 between axes 19 and 35 in either limiting position is shown to be only slightly less than the pitch of serrations 15; this insures that the two pawls will always engage the next-higher sawtooth 14 on the upswing of lever 18 so as to advance the piston head 13b by a step equal to that pitch during each downswing.
Figure 5 further shows the sides of pocket 32 diverging ln downwardly to an extent sufficient to let the pawl 25 maintain its dependlng attitude, with edge 39 remaining horizontal, while it swings relatively to the lever within its pocket as indicated by an arrow 34. The bearing mount 21 illustrated in Figure 5, serving as an anchor for one of the studs 20 articulating the lever 18 to socket 17, is also seen to lie within a cutout of prong 23 imparting the necessary mobility to the lever.
The steep ~ooth flanks 40 illustrated in Figure 4 are undercut so as to include with a radial plane an acute angle 42 of small size, e.g. about 10. This undercut, and the corres-ponding inclination of the lowe~ surface of the associated heel29, insures a firm interengagement during a downstroke as the front edge 39 is cammed into the intertooth gap by the flank slope under the exerted pressure.
The limiting positions of lever 18 are established, as seen in Figure 2, by a lug 46 on that lever alternately coming to rest on the top of sleeve 12 and on the underside of an over-hanging lip 47 rigid with socket 17. As further seen in Figure

2, a detent ring 48 is clamped between the upper end of cylinder 11 and the overlying shoulder 12a even as the lower edge of the sleeve abuts an annular rib lld of the cylinder. Ring 48l as _ g _ ~A

more clearly seen in the bottom view of Figure 6, has two generally T-shaped diametrically opposite incisions 51 so as to orm two pairs of strips 52 acting as retaining pawls for the piston rod 13~ Thus, each pair of strips 52 noxmally project far enough toward cylinder axis L to enter the gap between two sawteeth 14 of an associated serration 15, these strip~ having an angular profile gPnerally similar to that of heel 29 of the associated driving pawl 25. When lever 18 is upwardly retracted, strips 52 prevent a significant rise of piston rod 13 above the position into which it was last advanced. During the following forward swing, the strips 52 are cammed outward by the sloping tooth flanks 56 into the incision 51 as indicated by arrows 53 in Figure 4. In order to maintain the correct angular position of ring ~8, the same is provided with two holes 50 engaged by locator pins 44 which project from shoulder 12a as illustrated in Figure 2.
From Figures 1 - 4 it will be appar~nt that the saw-teeth 14 are formed by slanting cuts made in the outer peripheral surface 54 of rod 13, this surface being cylindrical except at the flat zones 55. When it is desired to decouple the piston from the operating lever 18, either for retracting it by means of handle 13a or for continuously depressing it into its bottom position, rod 13 is rotated ~y the handle 13a through 90 so that the flats 55 confront the pawls 25 and 52. This rotation, whether clockwise or counterclockwise, lets the pawls come ~o rest against the two flats and thus generate a slight resistance to further rotation, thereby insuring that the piston will not spontaneously leave its idle position. In the working position described above and shown in the drawing, the pawls 25 and 52 will have a similar stabilizing effect.

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Figure 7 illustrates a slightly modified arrangement wherein prongs 23' (only one shown) are unitary with tongues 25' acting as driving pawls, these tongues being elastically biased ~- similarly to retaining pawls 52 -- into engagement with sawteeth 14 of rod 13. This Figure also shows that the sawteeth may have rear flanks 40' lying in a radial plane instead of being undercut as in Figure 4. The latter feature, of course, could also be used with the embodiment heretofore described whereas, in turn, undercut flanks may co-operate with tongues 25' if their free ends are similarly profiled; the described advantage of positive interlocking,resulting from such an undercut, would then be preserved with the modification of Figure 7. That modification, furthermore, enables the clearance between prongs 23' and socket 17 to be reduced to a minimum since the prongs will no longer be required to yield outward during an upstroke of the operating lever; the position of prong 23' ~hown in Figure 7 corresponds to a retraction o~ the lever.
It will be understood that, in operation, cylillder 11 will be placed on a suitable support allowing the extruded pasta to flow from apertures llc into an underlying receptacle.
Nozzle lla could, of course, be replaced by one with differently shaped apertures when it is desired to vary the foxm of the pasta to be produced.

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Claims (20)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A manually operable press for the extrusion of a pasty mass through at least one shaping aperture, comprising:
a cylinder provided at one end with an extrusion nozzle and at an opposite end with a mounting member;
a piston head reciprocable in said cylinder and pro-vided with a piston rod projecting through said mounting member, said piston rod having two diametrically opposite longitudinal peripheral zones provided with respective serrations of generally sawtooth-shaped profile and identical pitch with steep rear sawteeth flanks facing away from said piston head;
an operating lever extending generally perpendicularly to said piston rod and having an extremity with two branches straddling the latter, said branches having inner surfaces provided with respective driving pawls having front edges engageable with said rear flanks of the corresponding serrations in a working position of said piston rod in which said longi-tudinal zones confront said inner surfaces, said extremity being articulated to said mounting member for swinging about a pivotal axis skew to the cylinder axis and more remote than said driving pawls from a free end of said lever, said lever being limitedly swingable in an axial plane of said cylinder about said pivotal axis for advancing said piston head toward said extrusion nozzle through the intermediary of said driving pawls on a forward swing and for retracting said driving pawls from said serrations on a reverse swing; and detent means on said mounting member resiliently engageable with said serrations in said working position for backstopping said piston rod upon an advance thereof by said driving pawls, said piston rod being rotatable into an idle position in which said serrations are disaligned from said feed pawls and from said detent means.

2. A press as defined in claim 1 wherein said extremity is bifurcate, said branches being a pair of resilient prongs articulated to adjoining lateral walls of said mounting member and straddled by said lateral walls with clearance for yielding outward together with said driving pawls on a reverse swing of said lever.

3. A press as defined in claim 2 wherein said driving pawls are fulcrumed on said prongs for swiveling about a common axis parallel to said pivotal axis and transverse to said cylinder axis.

4. A press as defined in claim 3 wherein said driving pawls have rear edges curved about said common axis and con-tacted by correspondingly curved overhanging ledges of said prongs.

5. A press as defined in claim 4 wherein said ledges are end walls of pockets of said prongs open toward said piston head, said driving pawls having shanks received in said pockets and heels including an obtuse angle with said shanks, said heels terminating in said front edges.

6. A press as defined in claim 5 wherein said pockets are traversed by pivot pins passing through said shanks along said common axis.

7. A press as defined in claim 3 wherein said front edges are formed by converging faces of said driving pawls fitting closely between said rear flanks and adjoining front sawteeth flanks of said serrations.

8. A press as defined in claim 7 wherein said rear flanks are undercut to include a small angle with planes trans-verse to the cylinder axis.

9. A press as defined in claim 1 wherein said detent means comprises an elastic ring in a plane transverse to the cylinder axis with incisions forming two pairs of radially deflectable strips separated by a small gap on opposite sides of a plane of symmetry which includes the cylinder axis and bisects said feed pawls in at least one position of said lever.

10. A press as defined in claim 9 wherein said mounting member forms an internal annular shoulder at said opposite end of said cylinder, said ring being disposed adjacent said shoulder with said strips projecting inward beyond the inner periphery of said shoulder.

11. A press as defined in claim 10 wherein said mounting member comprises a sleeve threadedly secured to said cylinder at said opposite end, said ring being clamped between said cylinder and said shoulder.

12. A press as defined in claim 11 wherein said shoulder and said ring are provided with interfitting formations pre-venting a relative rotation of said ring.

13. A press as defined in claim 3 wherein said pivotal axis and said common axis lie in a common plane transverse to said cylinder axis in a midposition of the swing of said lever.

14. A press as defined in claim 1 wherein said piston rod has two smooth longitudinal peripheral zones perpendicular to the serrated zones thereof, said smooth zones confronting said driving pawls in said idle position.

15. A press as defined in claim 1 wherein said driving pawls are unitary with said branches.

16. A press as defined in claim 1 wherein said driving pawls are unitary with said branches.

17. A press as defined in claim 1 wherein said cylinder, piston head, piston rod, driving pawls, operating lever and detent means consist of plastic material.

18. A press as defined in claim 17 wherein said plastic material is a polyamide reinforced with glass fibers.

19. A press as defined. in claim 1 wherein said mounting member is provided with abutments defining two limiting posi-tions for the swing of said lever.

20. A press as defined in claim 19 wherein said lever is substantially perpendicular to said cylinder axis in its limiting forward position.