PROCESS FOR SEALING A HOUSING FOR A MULTI-LAMP PHOTOFLASH UNIT

Abstract: A multi-lamp photoflash unit includes a plastic housing member (5) having a back portion (7) with a plurality of cavities (11), a reflector (35) nested therein and a multiplicity of flashlamps (45) located in the cavities. A front portion of the housing member folds over and is bonded by a knurled seal to the back portion. In the process, the front (9) and back (7) portions of the plastic housing member are positioned intermediate knurled head members (51, 53) which are energized to effect the desired knurled seal.

Description: KNURLED SEAL FLASHLAMP ARRAY TECHNICAL FIELD This invention relates to flashlamp arrays and more particularly to knurled seals for bonding a plastic housing member of a multi-lamp photoflash array. CROSS REFERENCE TO OTHER APPLICATIONS A concurrently filed application.in the name of Carl F. Kackenmeister bearing the Title "Folded Edge Seal For Flashlamp Array" is assigned to the Assignee of the present application, has a U.S. Serial No. (Attorney's Docket No. D-23,349) and relates to photoflash array sealing. BACKGROUND ART Numerous multi-lamp photoflash units have been developed, manufactured and marketed and all of these units include a number of photoflash lamps and reflectors enclosed within a plastic cover. In each case, structural integrity and security of the unit is dependent upon a mechanical or chemical bonding of a base and cover. In such units, techniques such as mechanical bonding and hot-melt adhesives and glues have been employed to seal multi-lamp photoflash units. However, such techniques do leave something to be desired especially when employed in a relatively high production operation. Other processes such as heat sealing, which is employed in the Magicube structure, or ultrasonic sealing as utilized in the Flash Bar or Flip Flash constructions, also have been and still are used with varying degrees of success. Also, heat sealing often employs a high intensity light source which is focused on the junction to be heated. Thus, the plastic absorbs light energy and heat and is softened in an amount sufficient to weld multiple layers together. Unfortunately, high temperature lamps used for heat sealing tend to exhibit life problems, cooling problems and maintenance problems all of which are undesirable. Moreover, the plastic material must be such that it will absorb sufficient heat to soften the materials. Such requirements do tend to present problems in a high production operation. Additionally, ultrasonic heating is dependent upon sonic energy which is transformed into friction and heat by the movement of parts in contact with one another. Thus, the materials to be bonded must be similar or have similar characteristics and a relatively low softening temperature in order to insure a good bond. Moreover, good contact and accurate mating of the parts to be bonded is necessary due to the limited amplitude of the vibrating parts. Thus, it is not uncommon to configure the ultrasonic source to match a given bond or seal design. SUMMARY OF THE INVENTION An object of the present invention is to provide an enhanced multi-lamp photoflash array. Another object of the invention is to provide an improved seal for bonding a multi-lamp photoflash array Still another object of the invention is to provide an improved surface whereat an improved housing member seal is located. These and other objects, advantages and capabilities are achieved in one aspect of the invention by a multi-lamp photoflash unit having a plastic housing member with back and front portions bonded together by a knurled seal. In another aspect of the invention, a sealing process for a plastic housing of a multi-lamp photoflash unit includes the steps of positioning mutliple layers of plastic between a pair of head members which are energized to effect a bonding of the plastic layers and is characterized by the provision of a knurled surface on at least one of the pair of head members. In still another aspect of the invention, apparatus for sealing a plastic housing member includes an energizing source coupled to a pair of head members for applying energy from the source to a back and front portion of a housing member and is characterized by a knurled surface on at least one of the head members. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded view of a preferred form of multi-lamp photoflash array utilizing the invention; and Fig. 2 is an elevational view of array of Fig. 1; and Fig. 3 is a graphic illustration of apparatus suitable to the fabrication of the array of Fig. 1. BEST MODE FOR CARRYING OUT THE INVENTION For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the accompanying drawings. Referring to the drawings, Figs. 1 and 2 illustrate a preferred form of multi-lamp photoflash array embodying the invention. The photoflash array includes plastic housing member 5 having a back portion 7 and a front portion 9. The back portion 7 includes a multiplicity of cavities 11 each having an off-set portion 13, to be explained hereinafter, and a pair of oppositely disposed sidewalls 15 which are in a plane substantially normal the opening of the cavities 11. The cavities 11 are spaced from one another by a bridging portion 17 and an aperture 19 is located in one or more of the bridging portions 17 to provide an exhaust passage for the cavities 11. Also, an outer ridge 21 of the back portion 7 of the plastic housing member 5 substantially surrounds the cavities 11 and includes a first relatively flat portion 23 adjacent the cavity 11 at each end of the array, a tapering portion 25 and a second relatively flat portion 27 joined to the first flat portion 23 by the tapering portion 25. The front portion 9 of the housing member 5 is of a light transmitting plastic and is formed to fold down and provide an envelope enclosing the contents of the back portion 7. This front portion 9 has an edge portion 29 connected by a tapering portion 31 to a relatively flat portion 33. Moreover, the edge portion 29, tapering portion 31 and flat portion 33 are of a configuration substantially identical to the first flat portion 23, tapering portion 25 and second flat portion 27 of the back portion 7 of the housing member 5 and are formed for bonding when the back portion 9 is folded to provide an enclosing envelope for the cavities 11. Referring for a moment to Fig. 1, the preferred multi-lamp photoflash array also includes a reflector unit 35 having a multiplicity of spaced reflector cavities 37 formed to nest within the cavities 11 of the housing member 5. Each of these reflector cavities 37 has a surface of reflecting material 39 thereon and includes a spaced portion 41 intermediate each pair of the reflector cavities 37. A hole 43 is provided in the spaced portion 41 and is aligned with the aperture 19 of the back portion 7 of the housing member 5. A multiplicity of flashlamps 45 formed for deposition within the reflector cavities 37 are affixed to a printed circuit board 47. This printed circuit board 47 includes a plurality of fingers 49 extending therefrom and formed for reception by the off-set portion 13 of the housing member 5. Thus, the reflector unit 35 is disposed within the cavities 11 of the back portion 9, the flashlamps 45 and fingers 49 of the printed circuit board 47 are located within the reflector cavities 37 and the package is in condition for sealing. In the sealing process, as illustrated by the apparatus of Fig. 3, the front portion 9 of the housing member 5 is folded to contact the back portion 7. Thereupon, the edge portion 29 tapering portion 31 and flat portion 33 are aligned with and contact the first flat portion 23, tapering portion 25 and second flat portion 27 respectively. Thereafter, one or more and preferably each one of the pairs 23-29; 25-31; and 27-33 of plastic layers are disposed intermediate a pair of head members 51 and 53. At least one and preferably both of the head members 51 and 53 has a knurled surface 55. This knurled surface 55 has a pattern wherein point contacts are created. These point contacts of the knurled surface 55 on each of the diametrically opposed head members 51 and 53 may be aligned to mesh or mis-aligned so as not to mesh depending upon the desired result. The pair of head members 51 and 53 are coupled to an energizing source 57 such as an ultrasonic energy source for example. Thus, the head members 51 and 53 are placed in contact with the plastic layers, 23-29 for example, and energized by the source 57 whereupon a knurled seal 59 of Fig. 2 bonding the back and front portions 7 and 9 of the housing member 5 is provided. Obviously, one or all of the pairs of plastic layers 23-29, 25-31 and 27-33 may be bonded utilizing the above-mentioned process and apparatus. Additionally, it is to be noted that the above-mentioned knurled surface technique wherein point contacts are formed in the plastic has permitted ultrasonic sealing without the necessity of providing energy directors as normally required when attempts were made to ultrasonically seal flat surfaces. As a result, the process and appartus is simplified and costs reduced. While there has been shown and described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined by the appended claims. INDUSTRIAL APPLICABILITY Thus, an enhanced multi-lamp photoflash unit has been provided wherein improved bonding of a plastic housing member is achieved. This improved bonding is dependent upon one or more knurled surfaces coupled to an energy source such as an ultrasonic energy source for example. In the illustrated example, the front and back portions of a plastic housing member are bonded by positioning of a portion thereof intermediate a pair of head members having a knurled surface. These head members are then energized to effect the desired knurled seal bonding the housing member. As previously mentioned, employment of the knurled surface permits energization by ultrasonic energy without the necessity of energy directors. Moreover, the utilization of such knurled surfaces to provide point contacts whereby energy is concentrated is also an advantage when other energy sources are utilized. For example, a heat source is adapted to bonding of surfaces which are configured to provide point contact thereDetween. Thus, a heat source and knurled surfaces provide an enhanced bond utilizinq a simplified apparatus and simplified process steps as compared with prior known techniques for bonding multi-lamp photoflash arrays.

Claims: WHAT IS CLAIMED 1. In a process for sealing a plastic housing member for a multi-lamp photoflash unit which includes the steps of positioning multiple layers of plastic between a pair of head members, contacting the plastic layers with said head members, and energizing said head members to effect a seal of said multiple plastic layers, the improvement comprising the step of providing a knurled surface on at least one of said head members whereby said plastic layers have a knurled pattern creating point contacts and concentration of sealing energy. 2. In the process of Claim 1 the improvement comprising the step of providing a knurled surface on each of said head memberswhereby sealing energy is concentrated at knurled point contacts of said plastic layers. 3. In the process of Claim 1, the improvement wherein said step of energizing said head members to effect a seal of said multiple plastic layers is in the form of sonic energy applied to said plastic layers by said head members. 4. In the process of Claim 1, the improvement wherein said step of energizing said head members to effect a seal of said multiple plastic layers is in the form of heat applied to said plastic layers by said head members. 5. In Åa plastic housing member sealing process for a multi-lamp photoflash unit having a foldable plastic housing member with a back portion having a plurality of cavities for receiving flashlamps and a light transmitting front portion, said sealing process including the steps of positioning said back portion and front portion of said plastic housing member between a pair of head members, contacting said back and front portions of said plastic housing member with said head members and energizing said head members to effect a seal between said back and front portions of said plastic housing, said process characterized by the improvement comprising the step of providing a knurled surface on at least one of said head members contacting said back and front portions of said plastic housing whereby a knurled pattern providing point contacts and sealing energy concentration is provided on said back and front portions of said plastic housing member. 6. In the process of Claim 5, the improvement comprising the -step of providing a knurled surface on both of said head members whereby enhanced sealing of said plastic back and front portions is effected. 7. In the process of Claim 5, the improvement comprising the step of providing a knurled surface on each of said head members with said knurled surfaces aligned to effect meshing of one surface with the other. 8. In the process of Claim 5, the improvement comprising the step of providing a knurled surface on each of said head members with said knurled surfaces aligned to insure non-meshing of one knurled surface with the other. 9. In the process of Claim 5, the improvement comprising the step of applying sonic energy to said back and front portions of said plastic housing member from said energized head members. 10. In the process of Claim 5, the process of applying heat energy to said back and front portions of said plastic housing member from said energized head members. 11. Apparatus for sealing a plastic housing member of a multi-lamp photoflash unit wherein said plastic housing member includes a back portion having a plurality of lamp receiving cavities and a light transmitting front portion contacting said back portion, said apparatus including an energy source coupled to a pair of head members for applying energy from said source to said back and front portions of said housing member and characterized by the improvement wherein at least one of said pairs of head members has a knurled surface contacting one of said back and front portions of said housing member whereby said back and front portions are sealed to one another. 12. The apparatus of Claim 11 wherein each one of said pair of head members has a knurled surface contacting one of said back and front portions of said housing member. 13. The apparatus of Claim 11 wherein each one of said pair of. head members has a knurled surface and said knurled surfaces are aligned to provide meshing of one surface with the other. 14. The apparatus of Claim 11 wherein each one of said pair of head members has a knurled surface and said knurled surfaces are aligned to provide non-meshing of one surface with the other. 15. The apparatus of Claim 11 wherein said energy from said source is in the form of sonic energy. 16. The apparatus of Claim 11 wherein said energy from said source is in the form of heat. 17. A multi-lamp photoflash unit having a plastic housing member with a back portion having a plurality of cavities for receiving lamps therein and a light transmitting front portion, said unit characterized by the improvement wherein a knurled seal bonds said back and front portions of said housing member. 18. The multi-lamp photoflash unit of Claim 17 wherein one of said back and front portions is knurled and bonded to the other one of said back and front portions. 19. The multi-lamp photoflash unit of Claim 17 wherein said back and front portions are each knurled and bonded to one another. 20. The multi-lamp photoflash unit of Claim 17 wherein said plastic housing member has a reflector unit with a multiplicity of cavities formed to nest in said cavities of said back portion and to receive said lamps disposed therein and a knurled seal bonds said back and front portions of said housing member to provide an enclosure for said lamps and reflectors. 21. The multi-lamp photoflash unit of Claim 17 wherein said plastic housing member has a circuit board positioned intermediate a portion of said back and front portions thereof and a knurled seal bonds said back and front portions of said housing member external to said circuit board.

Inventors: BROADT, DAVID R., KACKENMEISTER, CARL F.
Applicants: GTE PRODUCTS CORPORATION
Application year: 1982
Main classification: G03B15
IPC codes: G03B15