US2732101A - Dispenser for pasty materials - Google Patents

Description

Jan. 24, 1956 F. sHN 2,732,101

DISPENSER FOR PASTY MATERIALS Filed Feb. l1, 1953 fl, l-

.Iliiinw /A/Pf/V FRIEDRICH S H n' DISPENSER FOR PASTY MATERIALS Friedrich Shn, Schwelm, Germany, assignor to Firma Gerdes & Co., Schwelm, Westphalia, Germany Application February 11, 1953, Serial No. 336,409 Claims priority, appiication Germany March 19, 1952 14 Claims. (Cl. 222-320) The present invention relates to dispensers.

More particularly, the present invention-relates to the dispensers for pasty materials such as mustard, catsup, mayonnaise, and the like.

As is well known, it is generally quite a diicult matter to move this type of pasty material from its container, and many solutions have been already proposed to solve this problem. Among these solutions are dispensers which have a piston and hollow piston rod located in the container to force the material therein out through the hollow piston rod upon movement of the piston into the container. This type of construction has not proved to be very satisfactory. Perhaps the simplest known construction of this type involves the tilting of a ring member to clampingly engage the piston rod for moving the same, but this ring member is generally made of a soft material which soon becomes worn so that the desired clamping lasts for only a short time. Another known construction of this type moves the piston and piston rod through the medium of a ratchet andratchet teeth, but this construction requires, in addition to a lever and a tiltable mounting therefor, a pawl and a tiltable mounting therefor and at least two springs to respectively act on the lever and pawl. Thus, this construction is quite elaborate and expensive because it requires bearings, pivot pins, fastening members, etc.

One of the objects of the present invention is to provide a construction, of the type in which the piston and piston rod are moved by a pawl and ratchet mechanism, which is far simpler than any known construction of this type.

A further object of the present invention is to provide a dispenser whose parts may be very quickly and easily assembled and disassembled Without the use of any tools whatsoever.

Yet another object of the present invention is to provide a dispenser which is exceedingly simple to clean.

An additional object of the present invention is to provide a dispenser which will operate satisfactorily over a long period of time.

A still further object of the present invention is to provide a dispenser which requires only one spring for operating both the pawl and a lever which carries the pawl.

Still another object of the present invention is to provide a bearing structure, for the turning parts of the dispenser, which is of an exceedingly simple construction.

A still additional object of the present invention is to provide a piston rod carrying ratchet teeth but guided in its movement through means other than the ratchet teeth so that the latter need not serve as a guide and therefore may be made, for example, together with the piston rod out of a transparent thermoplastic.

Also, it is an object of the present invention to provide a one piece piston which has a yieldable outer periphery engaging the container.

Another object of the present invention is to provide a dispenser capable of accomplishing all of the above objects while at the same time being made of a small num` ber of inexpensive and ruggedly constructed parts.

With the above objects in view, the present invention mainly consists of a dispenser which includes a container having a closed bottom and an open top, the latter being covered by a cover of the container. A piston is slidably mounted in the container for movement toward and away from the bottom thereof, and a hollow piston rod is fixed to the piston and communicates with the space located between the piston and the bottom of the container,

this piston rod extending through the cover. A plurality of ratchet teeth are joined to the piston rod at one side thereof and extend along the length thereof, and a lever which turnably engages the cover, is located between the latter and the container and has an operating end portion extending through the cover, this lever having a pawl in turnable engagement therewith for movement about a predetermined axis and located opposite the ratchet teeth. A single spring engages the pawl between its predetermined turning axis and the piston rod and urges the pawl and lever therewith toward the cover.

The novel features which are considered as characteristie for the invention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method of operation, to* get her with additional objects and advantages thereof, will be best understood from thhe following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. l is a partly sectional, elevational view of a dispenser constructed in accordance with the present invention;

Fig. 2 is a fragmentary, partly sectional view of the lower part of a dispenser similar to that of Fig. 1 but having a different type of piston;

Fig. 3 is a fragmentary sectional view of the top part of the cover of the dispenser as seen in the direction of arrow III of Fig. 1 and with a part of the structure broken away;

Fig. 4 is a View of the cover and its associated parts as seen from the underside thereof;

Fig. 5 is a fragmentary, elevational, partly sectional view of the cover and piston rod structure illustrated on an enlarged scale; and Y Fig. 6 is a view of the structure of Fig. 5 shown in a position different from that of Fig. 5. Y

Referring now to the drawings, there -is illustrated therein a container 16 having an open top and a closed bottom formed by the wall iti. The container is covered by a dished cover member il which may be removably connected to the container by threading or the like. The cover il is formed with a substantially central opening through which the piston rod i2 is axially movable while being secured against turning with respect to the cover, and the piston rod 12 carries a piston 13 at its lower end. The piston 13 is formed with a central opening forming a continuation of the interior of the hollow piston rod i2 so that the latter communicates with the space between the piston 13 and bottom 11i of the container liti. Thus, the material in the container` located between the piston and bottom 16 will move out of the container' through the hollow piston rod i2 as the piston i3 approachesrwall lh. The outlet end of the piston rod can be closed, when the device is not in use, by a cap le. l

In order to provide a slidable and sealing contact between the piston and side wall of container liti, the piston 13 of Fig. l is formed with an annular groove in which an annular elastic sealing ring i5, of rubber or the like, is located, the ring l5 having its outer rim extending from the periphery of the piston and engaging the inner surface of container 10, as shown in Fig. l. A differ- Ptentea Jan. 24, 1956,

e-,rsalolY n CF ent piston arrangement is shown in Fig. 2 where the piston 13' is made of a material which is yieldable in .thin sections and relatively rigid in thick sections, for example, a synthetic material such as polyethylene. The piston 13 is relatively thick and therefore substantially rigid at its central portion which is ofl a somewhat smaller diameter than the diameter ofthe interior of container 10. To this relatively thick, disc-like central portion of piston 1 3 there is integrally joined an outer thinner peripheral portion 13 which is yieldable and of a slightly greater' diameter, in its unstressed condition, than the interior of container 10 so as to slidably and sealingly engage the latter. The advantage of this form oftpisto'n construction resides in its particularly simple manufacture as well as in its good seal and easy slidability.

The hollow piston rod12, which in the example illustrated is of cylindrical form,k carries at one side saw-toothlike ratchet teeth 16. These teeth are of rectangular cross section in a plane perpendicular to the plane of the drawing. They may therefore be used to cooperate with a suitable. notch in the cover 11 for preventing thc turning of the piston and piston rod. However, in order to relieve the teeth 16 of this function, ribs 17 are provided along the piston rod 12 and laterally spaced from the teeth 16, these ribs 17 being locatedk in corresponding grooves 18 (Fig. 4) formed in the surface portion of the cover 1 1 which extends about the piston rod 12 so as to therefore prevent turning of the piston rod and cover with respect to each other while permitting the piston rod to move axially through the coverv11. It is therefore possible with the construction of the invention to make the piston rod and teeth 1 6 in one piece out of a transparent plastic.

A lever 19 is provided to bring about the intermittent advance of the piston and toothed piston rod 12 toward the bottom 14) of the container, this lever 19 turnably engaging the cover 1,1 at the interior thereof and having an operating end portion 20 extending through an opening of the cover to the exterior thereof. In its central portion the lever 19 is ring-shaped and located about the piston rod 12 with a large clearance. On opposite sides of this ring-shaped central portion, the lever 19 is substantially U-shaped. The lever 19 is in pivotal engagement with the cover 11 ata portion thereof on the side of the piston rod 12 opposite from the teeth 16, and a pawl 21 turnably engages the lever 19 at a part thereof at the toothed side of piston rod 12, the pawl 21 being located opposite the ratchet teeth 16, as illustrated, and cooperating with these ratchet teeth.

To the underside of the cover member 11, on the side thereof opposite from the ratchet teeth 16 of piston rod 12, a pair of plate portions 27 are fixed, located opposite each other, and each formed with a substantially U- shaped recess or notch 23 directed away from the cover 11 and facing downwardly. The left end of the lever 19, as viewed in Figs. l, and 6, is formed with a pair of opposite, integral extensions 22 which are located in recesses 23 of the plate portions 27, respectively, and engage the latter for turning movement so as to form the turning axis of lever 19.

As was mentioned above, the lever 19 has a pair of U-shaped portions located on opposite sides of the piston rod 12, and the U-shaped portion on the toothed side of the piston rod 12 is formed in its opposite side walls, respectively, with a pair of recesses or notches 24 which are also substantially U-shaped and which are directed away from the cover 11 and face downwardly toward the bottom wall of container 1G. The pawl 21 is provided with a pair of opposite integral extensions 26, 22 which are respectively located in the recesses 24 of lever 19 and engage the latter for turning movement. Thus, the need for any special bores, bearings and pivot pins is entirely eliminated with the structure ofthe invention.

The pawl 21 is urged by a wire spring 25 about the pivot axis formed by projections 26, 22 of pawl 21 toward Cil the teeth 16. As is apparent from the drawings, the spring 25 engages the pawl 21 on the side thereof opposite from the piston rod 12 and between the turning axis of the pawl and the piston rod 12. The lever 19 is shown in Fig. 5 in its rest position, and in this rest position the left top end portion of pawl 21, as viewed in Fig. 5, extends through an opening of the lever 19 and engages the underside of the cover 11 to cooperate therewith under the influence of the spring 25 to be turned away from the teeth 16. The spring 25 has opposite free end portions 25' located in suitable grooves of the cover 11, so that the latter carries the spring 25, and the spring 25 is provided with an intermediate substantially U-shaped portion 2S having opposite legs interconnected by a third leg which engages the pawl as shown most clearly in Fig. 6.

The portion 25 of spring 25 extends in a direction substantially parallel yto the piston rod 12 and urges the pawl 21 and lever 19 upwardly toward the cover in a direction substantially parallel to the piston rod 12. Inasmuch as thc spring 25 engages the pawl 21 at a part thereof laterally spaced froml its turning axis, and since the spring 25 acts through the projections 26, 22 of pawl 21 on the lever 19 at a part thereof laterally spaced from its turning axis, the single spring 25 serves to maintain both the pawl 21 and lever 19 in the rest position shown in Fig. 5.

The dispenser operates as follows:

When the container 10 is separated from the remaining parts ofthe dispenser, this container may be filled with the material to be dispensed, such as mustard, catsup, mayonnaise, or the like. Then the piston 13 is slipped into the container 1i) until'k it engages the top surface of the material therein. The cover 11 is then placed about the piston rod 12, with the ribs 17 extending through the grooves 1S of the cover 11, and the latter is screwed onto the container 1,0. The lever 19 and' pawl 21 are maintained in position on the cover 11 by the spring 25;

Thus, the dispenser is ready for use, and the parts are in the position shown in Fig.V 5. To use the dispenser, the outer operating end portion 20-of lever 19 is depressed so as to turn the lever 19 about the axis formed by its projections 22, and in this way the pawl 21 is moved away from its position in engagement with the cover 11 so that it turns ina clockwise direction, as viewed in Figs. 5 and 6, under the influence of spring 25; The pawl 21 thus moves into engagement with one of the ratchet teeth 16, asshown in Fig. 6, and' upon further depression of the operating end portion 20 of lever 19-the downward movement of pawl 21l moves the piston rod 12 and the piston 13 therewith downwardly to press the material in the container upwardly through the piston rod 12,

Assuming that the piston and piston rod have been moved into the container suiciently to iill the hollovl piston rod 12 withthe material to be dispensed, it is evident that the depression of the operating end portion 20 of lever 19 will cause material from the container tov move into the piston rod 12 and to. push materiall adjacent the top end portion of piston rod 12 out of the latter, the cap 14 havingV beenA removed. It is evident that the amount of material dispensed will depend on. the length of the stroke` which the operator gives to the lever 19. Upon release of. the lever 1.9.y the. Serina 25 moves the latter together withthe pawl 21 back to the positionillustrated in Fig. 5 where the pawl21 no longer engages. the

' teeth 16.

It will be understood thatreachofV the elements described above, or two or more together, may also find a useful application in other types of dispensers differing from the types describedabove;

While the inventionhas been illustrated and described as embodied inA dispensersfor pasty materials, it is not intended to be limited to the details shown, since various modifications` and structural changes may. b e made without departing'inanyway-fromthespirit of the presentA invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod xed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover, being located between the latter and `said container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith toward said cover.

2. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward andaway from said bottom thereof; a hollow piston rod iixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover, being located between the latter and said container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring carried by said cover, engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith toward said cover, said pawl having a rest position in engagement with said cover and said spring turning said pawl out of engagement with said ratchet teeth when said pawl engages said cover and approaches its rest position.

3. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality ot' ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover, being located between the latter and said container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring carried by said cover, engaging said pawl between said predetermined axis and said piston rod 'and urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward-said cover.

d. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof;,a hollow piston rod iixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably' engaging said cover, being located between the latter and said container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring carried by said cover, located on the opposite side of said pawl from said piston rod, engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward said cover.

5. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover at a part thereof located at a side of said piston rod opposite from said one side thereof, being located between said cover and said container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring carried by said cover, located on the opposite side of said pawl from said piston rod, engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward said cover.

6. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover' covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover at a part thereof located at a side of said piston rod opposite from said one side thereof, being located between said cover and said container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring carried by said cover, located on the opposite side of said pawl from said piston rod, engaging said pawl between said predetermined axis and said piston rod and-urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward said cover, said spring being in the form of a wire having opposite free ends engaging said cover and having an intermediate substantially U-shaped portion extending toward said cover in a direction substantially parallel to said piston rod and located in engagement with said pawl.

7. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover at a part thereof located at a side of saidl piston rod' opposite from said one side thereof for movement to andl from a rest position, being located between said cover and said container, and having an operating end portion extending through said cover; a pawl turnably engagingl saidV lever for movement about a predetermined axis and beingl located opposite said ratchet teeth; and a single spring carried by said cover, located 0n the opposite side of said pawl from said piston rod, engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward said cover, said pawl in said rest position of said lever engaging said cover and cooperating therewith to turn away from said ratchet teeth under the influence of said spring.

8. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover at a part thereof located at a side of said piston rod opposite from said one side thereof, being located between said cover and said container, being formed at a part located at said one side of said piston rod with a pair of recesses directed away from said cover, and having an operating end. portion extending through said cover; a pawl having a pair of opposite projections respectively located in said recesses and turnably engaging said lever at said recesses thereof for movement about a predetermined axis, said pawl being located opposite said ratchet teeth; and a single spring carried by said cover, located on the opposite side of said pawl from said piston rod, engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward said cover.

9. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a pair of plate portions joined to said cover at a part thereof located at a side of said piston rod opposite from said one side thereof, being located opposite each other and between said cover and container, and each being formed with a recess directed away from said cover; a lever having a pair of opposite projections respectively located in said recesses of said. plate portions and turnably engaging the latter at said recesses thereof, said lever having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring carried by said cover, located on the opposite side of said pawl from said piston rod, engaging said pawl between said predcterminedaxis and said-piston rod and urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward said cover.

10. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering saidV open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod fixed to said piston andcommunicatingwith the space located between the latterand saidv bottom of said container, said piston rod extending` through said cover; a plurality of ratchet'teeth joined to saidpiston rod at one side thereof and extending along the length thereof; a lever turnably engaging said4 cover at a part thereof located at a side of said piston rodoppositel from said one side thereof, being located between saidcover and container, having at said one side of said piston rod a U-snaped portion having opposite sides each ofA which is formed with a recess directed away from said cover, and said lever having an operating end portion extending through said cover; a pav-.fl having a pair of opposite projections respectively located in said recesses and turnably engaging said lever at said recesses thereof for movement about a predeterminedaxis, said pawl being located opposite said ratchet teeth; and a single spring carried by said cover, located on the opposite side of said pawl from said piston rod, engaging said pawl'between said predetermined axis and said piston rod and urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward said cover.

li. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof, said piston being made in one piece, having a relatively. thick central portion, and having an outer yieldable peripheral portion in sealing, slidable engagement with the inner surface of said container and being substantially thinner than said central portion; a hollow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod eX- tcnding through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover at a part thereof located at a side of said piston rod opposite from said one side thereof, being located between said cover and said container, and having an operating end portion extending through said cover; a pawl turnsbly engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring carried by said cover, located on the opposite side of said pawl from said piston rod, engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith in a, direction substantially parallel to said piston rod toward said cover.

l2. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof, said piston being made in one piece, having a relatively thick central portion, and having an outer yieldabie peripheral portion in sealing, slidable engagement with the inner surface of said container and being substantially thinner than said central portion, said piston being made of polyethylene; a hoilow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said contianer, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover at a part thereof located at a side of said piston rod opposite from said one side thereof, being located between said cover and said container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring carried by said cover, located on thc opopsite side of said paw] from said piston rod, engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith in a direction substantially parallel to said piston rod toward said cover.

i3. A dispensercomprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof; a hollow piston rod xed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover, being located between the latter and sai-d container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith toward said cover, said spring being in the form of a wire having opposite free ends engaging said cover and having an intermediate substantially U-shaped portion extending toward said cover in a direction substantially parallel to said piston rod and having a pair of opposite legs interconnected by a third leg located in engagement with said pawl.

14. A dispenser comprising, in combination, a container having a closed bottom and an open top; a cover covering said open top of said container; a piston slidably mounted in said container for movement toward and away from said bottom thereof, said piston being made in one piece, having a relatively thick central portion, and having an outer yieldable peripheral portion engaging said container and being substantially thinner than said central portion; a hollow piston rod fixed to said piston and communicating with the space located between the latter and said bottom of said container, said piston rod extending through said cover; a plurality of ratchet teeth joined to said piston rod at one side thereof and extending along the length thereof; a lever turnably engaging said cover, being located between the latter and said container, and having an operating end portion extending through said cover; a pawl turnably engaging said lever for movement about a predetermined axis and being located opposite said ratchet teeth; and a single spring engaging said pawl between said predetermined axis and said piston rod and urging said pawl and said lever therewith toward said cover.

References Cited inthe tile of this patent UNITED STATES PATENTS Holst May 31, 1927 Hammerschmidt Jan. 6, 1942

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