US3780283A

US3780283A - Percussion-ignitable flash unit having contact-actuable pre-energized strikers and photographic apparatus using such units

Info

Publication number: US3780283A
Application number: US00232303A
Authority: US
Inventors: J Poweska; J Stoneham
Original assignee: Sylvania Electric Products Inc
Current assignee: GTE Sylvania Inc
Priority date: 1968-10-11
Filing date: 1972-03-06
Publication date: 1973-12-18
Anticipated expiration: 1990-12-18

Abstract

A flash unit having percussion-ignitable flash lamps and individual striker elements releasably retained in a preenergized condition. The individual striker elements are mounted on the unit at a location for selective percussion firing of individual lamps upon striker release and individual access sites are provided on the unit to allow selective release of individual holding elements. A photographic apparatus cooperates with such units to effect selective release of individual striker elements in synchronization with picture-taking operations.

Description

United States Patent 1191 Poweska et al.

1 1 Dec. 18, 1973 Smith....

FOREIGN PATENTS OR APPLlCATlONS (135,443 9/1936 Germany 431/93 Primur lirumincr-Fred L. Bruun Attorney-Joseph C. Ryan PERCUSSION-IGNITABLE FLASH UNlT HAVING CONTACT-ACTUABLE PRE-ENERGIZED STRIKERS AND PHOTOGRAPHIC APPARATUS USING SUCH UNITS [75] Inventors: Joseph V. Poweska, Rochester;

Jeffrey R. Stoneham, Hilton, both of NY.

[731 Assignee: Sylvania Electric Products, Inc.,

Danvers, Mass.

[221 Filed: Mar, 6, I972 [21] Appl. No.: 232,303

Related US. Application Data [60] Continuation of Ser. No, 813,524, April 4, I969, abandoned, which is a division of Ser. No. 766,751, Oct. 11, 1968, Pat. No. 3,596,581.

[52] US. Cl. 240/l.3, 431/93 [51] Int. Cl. G03b 15/02 [58] Field of Search 240/13, 37, 37.l;

[56] References Cited UNITED STATES PATENTS 744,540 11/1903 Hammer 95/1 1.5 R

[57] ABSTRACT A flash unit having percussion-ignitable flash lamps and individual striker elements releasably retained in a pre-energized condition. The individual striker elements are mountedon the unit at a location for selective percussion firing of individual lamps upon striker release and individual access sites are provided on the unit to allow selective release of individual holding elements. A photographic apparatus cooperates with such units to effect selective release of individual striker elements in synchronization with picturetaking operations.

3 Claims, 14 Drawing Figures PAIENIEMEcmma 3380.283

sum 20? a I PATENIEMEB 18 ms sum 30? 3 PERCUSSION-IGNI'IABLE FLASH UNIT HAVING CONTACT-ACTUAELE PRE-ENERGIZED STRIKEIIS ANDPIIOTOGRAPIIIC APPARATUS USING SUCH UNITS CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. Pat. application Ser. No. 813, 524, filed Apr. 4, 1969, now abandoned, which is a division of U.S. Pat. application Ser. No. 766,751, filed Oct. 11, 1968, now U.S. Pat. No. 3,596,581.

Reference is made to commonly assigned U. S. Pat. application Ser. No. 765,930, entitled Multilamp Flash Unit," filed Oct. 8, 1968, now U.S. Pat. No. 3,612,849 in the name of David E. Beach and U.S. Pat. application Ser. No. 765,926, entitled Percussion Activatable Flash Units Having Individual Striker Ele merits and Photographic Apparatus for Using Such Units, filed Oct. 8, 1968, now U.S. Pat. No. 3,576,155 in the name of David E. Beach.

BACKGROUND OF THE INVENTION .paratus using such flash units.

2. Description of the Prior Art In order to obviate the necessity for providing electrical flash-ignition sources and circuits in photographic apparatus, percussion-ignitable photoflash lamps have recently been developed for use with photographic appparatus. Such percussion-ignitable photoflash units, in general, employ lamps having an envelope containing a combustible material such as shredded zirconium foil and a combustion supporting gas such as oxygen, sealed in the envelope at a pressure of several atmospheres. A percussion activatable ignition tube is provided at the bottom end of such lamps, with the top of the ignition tube opening into the lamp envelope and the bottom end of the tube closed and extending outside the envelope to a location suitable for percussion striking.

One such lamp is disclosed in U.S. Pat. application Ser. No. 765,930, entitled Multilamp Flash Unit, filed Oct. 8, 1968 in the name of David E. Beach. In this unit, the ignition tube contains an anvil rod coated with percussion-ignitable material such as a mixture of zirconium and fulminate; and, upon striking the tube the material is activated and ignites the combustibles in the envelope through the open end of the ignition tube.

Another type of percussion-ignitable photoflash lamp is disclosed in copending U.S. Pat. application Ser. No. 765,926, entitled Percussion Activatable Flash Units Having Individual Striker Elements and Photographic Apparatus for Using Such Units, filed Oct. 8, 1968, in the name of David E. Beach. In the flash units disclosed in this application, a percussion cap is provided at the bottom of the ignition tube; and upon striking of the cap, a primer charge in the tube is ignited by the cap and in turn ignites the combustibles in the lamp envelope. In this latter-mentioned application a percussionignitable flash lamp is disclosed as it can be assembled in a unit with a percussion striker which is held in a pre energized condition by a movable latch member that is movable to release the striker to effect ignition of the lamp.

SUMMARY OF THE INVENTION The present invention provides an improved preenergized, percussion-ignitable flash unit. One feature of the present invention provides a pre-energized, percussion-ignitable flash unit in which the energized striker unit can be positively contacted and dislodged from a stationary retaining protrusion on the unit base. This feature of the present invention eliminates necessity for a releasing latch member in the unit and thereby simplifies construction of the unit and reduces the liklihood of accidental firings. Another feature of the present invention provides an improved torsion spring striker construction for use in percussionignitable flash units and which enables application of large torsion forces to effect percussion firing.

It is therefore an object of the present invention to provide an improved pre-energized, percussionignitable flash unit.

It is another object of the present invention to provide a flash unit having pro-energized striker elements which are contact-actuatable.

Another object of the present invention is to provide a pre-energized, percussion-ignitable flash unit of simplified construction and assembly.

Another object of the present invention is to provide a pre-energized, percussion-activatable flash unit which reduces the liklihood of accidental lamp-firing.

Yet another object of the present. invention is to provide a multilamp, percussion-ignitable, photoflash unit having pre-energized striker construction of an improved type.

Still another object of the present invention is to provide percussion-ignitable photoflash units having preenergized torsion spring strikers.

DESCRIPTION OF THE DRAWINGS The above and other objects and advantages will be apparent to one skilled in the art from the following description of preferred embodiments of the invention with reference to the accompanying drawings in which like numerals denote like characters and wherein:

FIG. 1 is a perspective view, with portions removed for illustration, of one embodiment of multilamp flash 1 unit in accordance with the present invention, mounted on photographic apparatus;

FIG. la is a partial section of the flash unit in FIG. 1, as indicated, showing a manner of mounting the preenergized striker elements of that unit; I

FIG. lb is a partial section similar to FIG. Ia but showing an alternative manner of mounting the preenergized striker elements in that unit;

FIG. 2 is a perspective view of a multilamp flash unit with portions removed for illustration and showing another embodiment of the present invention;

FIG. 3 is a perspective view of a multilamp flash unit with portions removed for illustration and showing yet another embodiment of the present invention;

FIG. 4 is an enlarged top view of the flash unit shown in FIG. 1 having parts omitted for purpose of illustration;

FIG. 4a shows the unstressed configuration of the springs shown in FIG. 5;

FIG. 5 is a sectional view taken along the lines 5-5 in FIG; 4;

FIG. 6 is a fragmentary view of a portion of the unit shown in FIG. but showing the striker element in its released position;

FIG. 7 is a perspective view of a camera showing one embodiment of actuating structure with which the present invention may be employed, therefore, portions of the camera housing being removed and parts omitted for purpose of illustration;

FIG. 8 is a perspective view of the actuating elements shown in FIG. 7 when in a cocked position; and

FIGS. 8a and 8b disclose a modification of the retaining element of the flash unit and actuating member;

FIGv 9 is a top sectional view of a portion of the camera shown in FIG. 7 showing the socket rotating mechanism of the camera.

In FIG. I a multilamp flash unit I constructed in ac' cordance with one embodiment of the present invention is shown detachably mounted on a photographic apparatus 2, in this instance a camera. Because photographic camera having structure to detachably receive and sequentially index electricallyignitable multilamp photoflash units are generally known, the present description will be directed to particular elements of such cameras which form a part of or cooperate more directly with the present invention, elements not specifically shown or described herein being understood to be selectable from those known in the art.

By referring to FIGS. 1-3 it can be seen that each of flash unit embodiments I, II and III include a plurality of percussion-ignitable flash lamps 3 which are mounted with their individual reflectors 4 around the central axis of a base 5 to form an assemblage which is generally cubic in configuration. The base 5 suitably can be formed of molded plastic. By refer briefly to FIG. 5 it can be seen that each of the flash units shown in FIGS. l-3 have a downwardly extending hollow post 6 adapted to be mounted in a socket on the camera 2 in a known manner. The upright walls 7 of the unit are transparent and a top 8 is provided to complete the package enclosure.

The flash lamp 3 of the units I, II and III are similar to the type disclosed in US. Pat. application Ser. No. 765,930, entitled Multilamp Flash Unit, filed Oct. 8, 1968, in the name of David E. Beach in that the units are provided with a hollow ignition tube 9 which opens on its top into the flash lamp envelope. These tubes can contain an anvil rod coated with a primer charge such as a composition of zirconium and fulminate like the ignition tubes in the above mentioned Beach application, or can contain other percussive-activatable charges such as are known in the art. However, it will be noted that the ignition tubes 9, in these units, need not extend outside the container because of the novel preenergized striking device provided in accordance with the present invention.

Referring now to FIGS. 1 and 4-6, the particular flash unit embodiment I of the present invention shown therein will be described in more detail. It can be seen that the strikers 10 of this embodiment are in the form of a unitary spring member having an inverted U- shaped upright portion 11 and two generally horizontal striker portions 12. The flash unit I utilizes two of the spring elements 110 so that with two striker portions 12 on each spring 10, each of the four flash lamps 3 is provided with an individual striker element 12. The spring members 10 are mounted with the inverted U-shaped portions thereof in diagonally opposite corners of the unit and extending generally normally upward from the base 5. The U-shaped members 11 can be supported with respect to the unit by a hollow sleeve 13 as shown in FIGS. 1 and la or, alternatively, clamped rigidly at their top to the unit by web 13/ as shown in FIG. 1b, in a manner which substantially prevents transmission of torsional stress between the legs of the U member 11.

The striking portions 12 of each spring 10 are generally perpendicular to the upright portions 11 so as to extend generally parallel with respect to the interior of base 5. The spring 10 is formed so that the striker portions 12, in their unstressed condition, are generally parallel and formed as extensions of the upright por tion, bent The unstressed configuration of a spring 10 can be seen in FIG. 4a; however, the construction of the springs unstressed configuration can vary in accordance with characteristics of the material used and the energy desired for percussion.

It can be seen that when the springs 10 have been mounted in the flash unit I and striker arms 12 stressed to the positions shown in FIGS. 1 and 4, considerable torsional restoring forces in portions I1 urge the striker arms 12 towards the ignition tubes 9 of the flash unit.

As shown in FIG. 5, the bottom ends of ignition tubes 9 can be embedded in the base 5 to obtain rigid support and a back-up ring 50 can be moulded in the base to further support the tubes during percussion. The base 5 is provided with upwardly extending posts or stops 14 which provide means for dislodgably restraining the free ends of striker portions 12 under stress so that the spring is in a condition which is herein termed preenergized.

As mentioned above, the force urging the strikers 12 towards ignition tubes 9 include a large torsional restoring force resulting from the twisting of the upright portion 11. Further, it can be seen that when the upright portion is mounted as by a sleeve 13 as shown in FIGS. 1 and la, the torsional forces acting to restore the strikers are derived from both legs of the upright portion I2. However, when the top of striker 10 is clamped by web 13' as shown in FIG. lb the torsional restoring force for any one striker is derived substantially from only one leg of the upright portions 11 of springs 10.

The base 5 also includes four openings I5 to the exterior of the flash unit I. The openings 15 are in the illus' trated embodiment located intermediate the posts 14 and mounted upright portions 11 of the spring 10 and beneath the striker portions 12 when in their preenergized positions shown in FIGS. 1 and 5. However, it will be appreciated from the following description of operation that the free ends of striker portions 12 can be formed to extend beyond posts 14 and under free ends the pre-energized springs 12.

By referring to FIGS. 4-6 it can be seen that when an actuating member such as 72 is moved upwardly from the exterior of the flash unit I through one of the access sites defined by openings 15, the striker portion 12 associated with that opening will be moved upward to a position in which is no longer restrained by stop 14 and is free to be moved by the restoring forces of spring 10 into percussion contact with the ignition tube 9 located in its firing path.

It will of course be appreciated that in order to prevent accidental dislodging of the striker portions 12, the posts 14 can be slightly ramped over the pins or that the striker portions 12 can be weakly secured to the posts as by embedding the wire ends partially in the posts l4 or base 5. Also it is to be noted that the spring can he formed so that the mounted striker portions 12 have a slight downward bias against the base 5 to further prevent accidental firings.

Referring now to FIG. 2,the flash unit embodiment ll of the present invention will be described. ln flash unit ll. the wire strikers are formed as cantilever springs with fixed ends 21 embedded in the base 5 and free ends 22 dislodgably restrained by posts 23. A plurality of'openings 24 provide access for an actuating member to dislodge the strikers 20 from posts 23 in the manner described with respect to FIG. 1.

ln FIG. 3 it can be seen that the springs 30. of flash unit Ill are similar to those shown in FIG. 1 in that torsional restoring forces are applied by upright members 31 to cause the striker portions 32 to move into percussion contact with ignition tubes 9. However, in this instance, each striker portion 32 is provided with an individual inverted U-shaped member; and the four inverted-U members of the unit Ill are mounted in the center of the flash unit by a sleeve 33. The sleeve 33 can be secured to the top of the flash unit lll. Again restraining posts 34 and access openings35 are provided so that actuation of ignition-tubes 9 can be effected in the same manner described with respect to the embodiments shown in FlGS. 1 and 2.

It will be appreciated that individual striker elements of the present invention need not take the specific forms illustrated but can include other biased element which can be dislodgably retained within the flash unit in a pre-energized condition and which, upon dislodging actuating contact will effect percussion activation of an associated flash lamp.

it also is to be noted that the striker and restraining elements need not be enclosed in the flash unit in the specific manner shown herein; however, it is very desirable that such elements be protected by structure of the unit in such a fashion that accidental firing is not likely. For this purpose, easily rupturable protective structure can be provided to prevent accidental activation of the holding elements. in accordance with the present invention, it only is necessary that the unit be provided with actuating sites with which an actuator member of a photographic apparatus can cooperate to dislodge a preenergized striker element.

It will also be appreciated that the present invention can be utilized with flash units having any number of flash lamps in that a corrresponding number of contactdislodgable, preenergized striker elements can be provided for any number of flash lamps in the unit.

Referring now to FIGS. 7-9 one embodiment of photographic apparatus with which the flash unit of. this invention may be employed is provided for selectively moving into dislodging contact with preenergized striker elements in a flash unit such as that in FIGS. 1-5, will be described.

The camera comprises an exterior housing 41 and an interior frame 42 on which various operating elements of the camera are mounted. ln FIG. 7 it can be seen that a socket 43, of a known type adapted to detachably receive and support a flash unit with a base 5 such as is shown in FIG. 5, is provided in an opening on the top of housing 41.

In FIG. 7 it can be seen that the camera 40 has a film advance wheel 45 with an operating lever 46, the wheel 46 being connected to a filmdrive shaft 47 which successively advances photographic film inserted in the camera in a known manner. The wheel 45 also has a lug 48 formed on its periphery, the purpose of which will be subsequently described.

A shutter release lever 50 is slidalhly mounted on pins 51 for movement in a vertical direction and is urged up wardly by shutter release spring 52. In FIG. 7 is can be seen that the shutter release lever includes an operating top 55 and has extending horizontally therefrom a retaining arm 53' which terminates in a shutter release latch 54.

A shutter driver is mounted in the camera on suitable means (not shown) for rotation on pin 61 in operative association with the shutter release latch 54 and the camera shutter (not shown). The shutter driver is biased by shutter drive spring 62 for rotation in a counterclockwise direction as viewed from the top in FIG. 7 and includes a cocking arm 63, shutter actuating arm 64 and retaining arm 65 which will be further described hereafter.

' An actuating plunger is slidably mounted in a bore in the frame 42 of the camera and urged upwardly by an actuating spring 71 so that, when released from its cocked position, an actuating pin 72 on the upper end of plunger 70 will pass through an actuating opening 73 in the camera top. The actuating opening 73 and plunger 70 are aligned with respect to socket 43 so that the access opening 14 associated with a forwardlyfacing lamp 3 of a percussion-ignitable unit such as disclosed in FIG. 1, will be aligned with these elements when in the socket 43. The actuating plunger 70 has a cocking pin 76 and a retaining notch formed on the bottom end thereof at a location for cocked engage ment by retaining arm 65 of shutter driver 60.

A cocking slider 80 is mounted for horizontal movement in the camera by means not shown and has an opening 81 engaged by lug 48 of film advance wheel 45. The slider 80 includes a shutter driver cocking arm 82 and a ramped end 83 adapted to contact cocking pin 76 and move plunger 70 downwardly against spring 71.

In FIG. 7 the parts of the camera are shown during a picture-taking operation with shutter release lever 50 partially depressed; whereas in FIG. 8 the parts are shown in a cocked position after film wind and ready for a picture-taking operation.

By referring to FlGS. 7 and 8 it can be seen that when the camera is in the ready condition shown in FIG. 8 and shutter release lever 50 is depressed, the shutter release latch 54 releases shutter driver 60 so that arm 64 can move counterclockwise to actuate the camera shutter (not shown) in a known manner. This movement of the released shutter driver 60 also causes retaining arm 65 to release actuating plunger 70 so that the actuating pin 72 is moved upwardly through the actuating opening 73 and into the aligned access opening 14 of an inserted flash unit 1. This action releases the individual spring 12 which is associated with the for wardly facing flash lamp 3 and provides photoflash in synchronization with the camera shutter.

During film advance, the film advance wheel 45 is rotated counterclockwise causing slider 80 to move right to the position indicated by the dotted lines in FIG. 8. Rightward movement of the slider 80 causes ramped end 83 of the slider to contact pin 76 and move the actuator plunger 70 downward. Also during this right ward movement the shutter driver cocking arm 82 en gages and moves the shutter driver clockwise against spring 62 and over shutter release latch 54 to its cocked position. The final stages of clockwise rotation of the shutter driver 60 causes its retaining arm 65 to move into notch 75 of the lowered plunger 70 thereby retaining the plunger in the cocked position. After the film advance wheel 45 has been returned to its original position shown in PK]. 7 the camera elements are cocked and ready for another picture-taking operation.

By referring to FIGS. 7 and 9, the mechanism which provides socket rotation in proper cooperation with film advance and the cocking of actuating plunger 70 can be seen.

As shown in FIG. 7, the slider 80 has formed thereon an upper arm 85 which is pinned to a socket rotating arm 86 that can be more clearly seen in FIG. 9. As shown in FIG. 9, a spring 87 urges socket rotating arm 86 towards slider 80 and against a stop 88 on upper arm 85. The rotating arm has a claw 89 formed on its forward end that is adapted to engage ears 91 which are formed on the lower portion of socket 43.

It can be seen that during film advance the slider 80 first cocks plunger 70 thereby withdrawing the pin 72 from an inserted flash unit and moves rotating arm into contact with an ear 91 on socket 43 as indicated by the dotted position a in FIG. 9. Further movement of the slider to dotted position 6 effects rotation of the socket 43 with the pin 72 out of an interfering position. The socket is indexed and held in the advanced position by engagement with a spring loaded detent 92 in notches 93 of the socket 43.

The invention has been described in detail with particular reference to preferred embodiments thereof but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. In a substantially enclosed flash unit of the type having a base and at least one percussion-ignitable photoflash lamp with an individual activating element and reflector mounted within a transparent-walled package, the improvement comprising:

a striker including a spring portion and a movable striker portion and being mounted on said unit in a manner such that said striker portion is urged by said spring portion along a striking path towards and into percussion-contact with said activating element of said lamp;

stationary stop means, located along said striking path and spaced from said activating element, for restraining said striker portion in an energized condition, said stationary stop means comprising a protrusion extending upwardly from said base into said striking path; and

means for providing access to said striker portion located beneath said striker portion when said striker 8 portion is restrained by said protrusion whereby a dislodging force can be imparted to said striker portion from the exterior of said unit, said access providing means comprising an opening through said base.

2. In a multilamp photoflash unit of the type having a plurality of percussion-ignitable flash lamps and individual lamp reflectors mounted within and in operative relation about a central axis of a transparent-walled container, the improvement comprising:

a plurality of spring-biased percussion strikers located within said container, said strikers being located respectively in operative relationship with and biased towards said flash lamps;

a plurality of stationary stop members, said stop members being constructed and located respectively in position to dislodgably restrain said strikers in a pre-energized condition, spaced from said flash lamps; and

said container including a base on which said flash lamps are mounted, said stop members respectively including protrusions extending generally normally from said base within said container, and a plurality of means defining openings through said base, said openings being respectively located in a manner such that an actuating member can be extended therethrough and into said container to contact and raise said strikers above said protrusion.

3. A percussion-ignitable flash unit comprising:

a base having an upper surface;

at least one percussion-ignitable photoflash lamp mounted on the upper surface of said base;

a spring member having a movable striker portion which is mounted on said unit in a manner such that said striker portion is urged toward said lamp in a striking plane extending generally parallel to the surface of said base;

means for dislodgably restraining said striker portion in a pre-energized condition, spaced from said lamp, said restraining means comprising a stop member located in said striking plane at a position spaced from said lamp and contactable by said striker portion, said stop member extending generally normally from said base through and slightly beyond said striking plane; and

means on said base defining an actuating site in said base located in the proximity of said striker portion when in said pre-energized condition whereby a dislodging force can be imparted to said striker portion through said base, said actuating site comprising means defining an opening through said base exposing at least part of said striker portion, when in its energized condition, for contact from the side of said base opposite said striker portion.

Claims

1. In a substantially enclosed flash unit of the type having a base and at least one percussion-ignitable photoflash lamp with an individual activating element and reflector mounted within a transparent-walled package, the improvement comprising: a striker including a spring portion and a movable strikEr portion and being mounted on said unit in a manner such that said striker portion is urged by said spring portion along a striking path towards and into percussion-contact with said activating element of said lamp; stationary stop means, located along said striking path and spaced from said activating element, for restraining said striker portion in an energized condition, said stationary stop means comprising a protrusion extending upwardly from said base into said striking path; and means for providing access to said striker portion located beneath said striker portion when said striker portion is restrained by said protrusion whereby a dislodging force can be imparted to said striker portion from the exterior of said unit, said access providing means comprising an opening through said base.

2. In a multilamp photoflash unit of the type having a plurality of percussion-ignitable flash lamps and individual lamp reflectors mounted within and in operative relation about a central axis of a transparent-walled container, the improvement comprising: a plurality of spring-biased percussion strikers located within said container, said strikers being located respectively in operative relationship with and biased towards said flash lamps; a plurality of stationary stop members, said stop members being constructed and located respectively in position to dislodgably restrain said strikers in a pre-energized condition, spaced from said flash lamps; and said container including a base on which said flash lamps are mounted, said stop members respectively including protrusions extending generally normally from said base within said container, and a plurality of means defining openings through said base, said openings being respectively located in a manner such that an actuating member can be extended therethrough and into said container to contact and raise said strikers above said protrusion.

3. A percussion-ignitable flash unit comprising: a base having an upper surface; at least one percussion-ignitable photoflash lamp mounted on the upper surface of said base; a spring member having a movable striker portion which is mounted on said unit in a manner such that said striker portion is urged toward said lamp in a striking plane extending generally parallel to the surface of said base; means for dislodgably restraining said striker portion in a pre-energized condition, spaced from said lamp, said restraining means comprising a stop member located in said striking plane at a position spaced from said lamp and contactable by said striker portion, said stop member extending generally normally from said base through and slightly beyond said striking plane; and means on said base defining an actuating site in said base located in the proximity of said striker portion when in said pre-energized condition whereby a dislodging force can be imparted to said striker portion through said base, said actuating site comprising means defining an opening through said base exposing at least part of said striker portion, when in its energized condition, for contact from the side of said base opposite said striker portion.