A FASTENING ARRANGEMENT FOR HOLDING TOGETHER THE TWO SECTIONS OF A TELEPHONE HANDSET CASING

Abstract: Fastening arrangement for holding together the two sections (1, 2) of a telephone handset casing. The microphone (21) and/or the telephone receiver is held in position in the casing by means of a clamping element (16). The clamping element is provided with a cam surface (23) which is close to a steady support in the casing section which contains the microphone or the telephone receiver when the two casing sections are pressed together, the clamping element (16) is urged diagonally downwards. During this movement the clamping element grips a flange (24) in the upper casing section (1) and presses it downwards so that the casing sections are firmly held together.

Description: A FASTENING ARRANGEMENT FOR HOLDING TOGETHER THE TWO SECTIONS OF A TELEPHONE HANDSET CASING. " TECHNICAL FIELD The present invention relates to a fastening arrangement for holding together two sections of a telephone handset casing. BACKGROUND ART It is previously known to construct telephone handsets consisting of two sections, a lower section and an upper section, which are hold to- 5 gether by means of screws in the hand grip to form a complete casing. During mounting, the microphone and the telephone receiver are placed in the Lower section, the upper section hooked over one of the ends of the lower section. The screws in the hand grip are then tightened to press the two casing sections together. When tightening the screws also 10 the microphone and the telephone receiver are pressed towards the bottom of the lower section by means of clamping rings or plates. De¬ pending on the distance between the fastening screw and the end of the casing where the sections are to be pressed together, bending strains with associated cracks can arise. DISCLOSURE OF THE INVENTION ι 15. The object of the invention is to provide an arrangement eliminating the mentioned bending strains by firmly holding together the distant ends of the sections forming the casing. The invention is characterized as it appears from the claims. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described more in detail, by way of example 0 and with reference to the accompanying drawings, in which Fig. 1 shows one embodiment of a hand set according to the invention just prior to fastening the two casing sections together. ^JHET Fig 2. shows the same set after fastening the sections together. Fig 3. shows in cross-section the microphone end of the hand set during mounting. Fig. shows the same arrangement as Fig. 3 in the mounted state, Fig. 5 shows the lower section with a clamping plate in plane view partly in section, and Fig. 6 shows the hand set as seen from the microphone end, partly in section. BEST MODES FOR CARRYING OUT THE INVENTION The upper casing section of the handset is designated 1 in Fig. 1 and the lower casing section is designated 2. At one of its short ends the lower section 2 is provided with a groove 3 into which a hook 4 on the upper section can engage so as to provide a pivot point about which the upper section can pivot until the opposite end is in close contact with the end of the lower section. In previously known handsets, the fastening has been carried out by means of screws which when tightened act to press the two sections together as well as causing a clamping ring or plate to press the microphone and the telephone receiver, respectively, towards the bottom of the lower section. It appears that, when pressing together the ends of the sections by means of the screws, a considerable bending strain arises due to the distance between the screw and the end of the casing. This can result in cracks which can be prevented by a clamping plate 6 which is schematically indicated in Fig. 1 and whose purpose is not on¬ ly to hold the microphone and/or the telephone receiver pressed against the bottom of the lower section, but also to keep the two sections pressed against each other at one of the r ends. The clamping plate or ring has two pairs of studs 7 and 8 at the short side of the hand¬ set which, when the casing sections are tightened are urged ourwards, one of the pairs 18 slipping into the lower section 2 through the ~ guide openings 25 at the same time as a further pair of lugs 19 is pushed diagonally downwards in order to engage a flange 24 on the in¬ side of the upper section. Thus, the upper section is pressed towards the lower one and is kept in a stable position so that bending strains are prevented as will be explained more in detail below. Figs. 3 and 4 show -the clamping plate and its function in connection with the fastening of the upper and the lower sections. The lower section 2 has a stud 11 extanding inwards with a collar 12. Oppo¬ sitely, on the upper section a stud 13 extending inwards is provided having a hole 14 for the stud 11 and being provided with a thread 15 into which a screw 5 can be screwed in order to bring the two casing sections closer together by tightening. The clamping plate 16, shown in Fig. 5 in plan view by means of its fork-shaped end provided with • lugs 17 engages the stud 11. When the clamping plate is placed in the lower section 2 prior to assembly of the two casing sections the lugs 17 are approximately on a level with the upper edge of the stud 11 as shown in Fig. 3. The pairs of lugs 18 and 19 at the free ends of the forks' arms of the clamping plate 16 provide pairs of claws- 18 and 19, respectively, of which the claw pair 18, upon mounting, engages into the hole 25 in the lower section as appears from Figs. 3 and 5. The clamping plate is also provided with two projections 20 directed down¬ wards whose purpose it is to k-eep the microphone 21 in a pressed down position. Furthermore the clamping plate is provided with a resilient arm 22 which elastically obstructs displacement of the plate in a down- wards direction. Between the fork-shaped end of the clamping plate provided by the lugs 17 and the major portion of the clamping plate an interconnecting arm 23 forming an obtuse angle with these two parts is provided. ' A cam surface 24 on the inner side of the intercon- necting arm is in close contact with the collar 12. When, after placing of the clamping plate 16 between the casing sections as shown in Fig. 3, the screw 5 is tightened, the stud 11 is inserted into the hole 14 and the lower surface of the stud 15 exerts a force on the lugs 17. The cam surface 24 slides over the edge of the collar 12. In this way the clamping plate 16 is pressed diagonally downwards during elastic de- formation of the spring 22 as appears from Fig. 4. In the position shown in Fig. 3, the clamping plate 16 does not engage the upper casing section and, furthermore, the pairs of lugs 19 are not in close contact with the flanges 24 on the inner side of the upper section. Fig 3 shows the position before the tightening of the screw has started. In reality, however, the upper section is already pressed down suffi- ciently for the lugs 19 to be in a position higher than the flanges 24 when beginning the tightening of the screw. When, during the tightening the clamping plate 16 is displaced diagonally downwards, the pair of Lugs 19 grips the flange 24 and presses this downwards at the same time as the pair of lugs 18 is guided through the hole 25 in the out- wards direction. When the screw 5 is tightened the two sections are completely locked relative to each other and play or bending strains cannot arise. In Fig. 4 the wall part 26 (Fig. 3) has been removed to illustrate the position of the flange 24 after the Locking.

Claims: WHAT WE CLAIM IS : 1 A fastening arrangement for holding together two sections of a telephone handset casing in which at least one of the telephone com¬ ponents is retained in position by means of a clamping element, charac¬ terized in that the clamping element (16) is provided with a cam sur- face (24) which is in close contact with a fixed support (12) in one said section (2) so that, when the two sections are pressed together as a result of pressure from the other section said element is urged diagonally downwards towards said at least one telephone component as a result of said cam surface sliding over-said fixed support, said clamping element (16) further being provided with projections (19) which as a result of the diagonal movement of the clamping element (16) are brought into engagement with a flange (24) on the other section ( 1 ) in order to firmly- old the two casing sections together. 2 A fastening arrangement according to claim 1, characterized in that the clamping element (16) includes a pair of forks arms, whose respective ends carry said projections (19). 3 A fastening arrangement according to claim 1, characterized in that the clamping element (16) includes a resilient arm (22) which is elastically deformed during displacement of the clamping element. 4 A fastening arrangement according to claim 1, characterized in that the clamping element (16) is provided with guide elements ( 17) which keep the clamping element during its displacement in an unchanged position in the transverse direction of the handset. 5 A'f ' astening arrangement according to claim 1, characterized in that the clamping element (16) is provided with further projections (18) displaceable in holes in said one section to hold said clamping element steady during its displacement in said one section. C?'?I

Inventors: LINDBERG JOERGEN F, STROEMER CARL A, TRONSLIEN ERLING
Applicants: ERICSSON TELEFON AB L M, LINDBERG JOERGEN F, STROEMER CARL A, TRONSLIEN ERLING
Application year: 1980
Main classification: H04M1
IPC codes: G09G3, H04M1, H04N5