Apparatus suitable for cooperation with a cassette provided with magnetic tape, magnetic-head unit and magnetic-head for use in the apparatus, housing suitable for use in the magnetic-head unit, and method of manufacturing the magnetic-head unit

Abstract: An apparatus (1) has a magnetic-head unit (17) with a housing (18) in which a magnetic head (47) is situated. The magnetic head (47) has a head face (49) in which a gap end of a transducing gap (51) extends and a first mounting surface (107) perpendicular to a gap plane (59) through the transducing gap (51). The magnetic-head unit (17) has a front section (29) of which tape guides (31, 33) form part and which is provided with a second mounting surface (75), which is positioned relative to the first mounting surface (107) of the magnetic head (47). This results in an accurately defined position of the magnetic head (47) relative to the tape guides (31, 33).

Description: The invention relates to an apparatus suitable for cooperation with a cassette provided with a magnetic tape, which apparatus comprises tape-transport means for transport of the magnetic tape in its longitudinal direction, and a magnetic-head unit, which unit comprises a housing holding a magnetic head for reading and/or writing information on magnetic tape, which head has a head face towards the tape, if present, and which head face has a transducing gap terminating in the head face and defining a gap plane which is at least substantially perpendicular to the head face, and which unit comprises a pair of tape guides, each guide located at a respective opposing lateral side of the transducing gap and including a guide surface for engaging a major side of the magnetic tape, which guides define a tangent plane connecting the guide surfaces, the magnetic head being mounted in the housing with a first mounting surface parallel to and cooperating with a second mounting surface of the housing. The invention also relates to a magnetic-head unit for use in such apparatus. The invention further relates to a method of manufacturing a magnetic-head unit comprising a housing and a magnetic head, which method comprises the following steps: manufacturing the magnetic head provided with a first mounting face, a head face, and at least one transducing gap, manufacturing the housing provided with a second mounting face, tape guides and height guides, positioning the magnetic head in the housing, causing a gap plane through the transducing gap to be oriented perpendicularly to a connecting line between the height guides, and affixing the magnetic head in the housing. An apparatus, a magnetic-head unit and a method of the type defined above are known from EP-A 0 120 518. For the reproduction of information recorded on a magnetic tape it is desirable that the position of the transducing gap of the magnetic head relative to the magnetic tape is the same as during the process in which this information has been recorded on the magnetic tape. If this position is not the same this will result in signal loss during information reading. Moreover, it is desirable that the position of the magnetic tape relative to the magnetic head is the same for each apparatus. This is in order to ensure that a recording made on one apparatus can be reproduced without signal loss by means of another apparatus. During the recording or reproduction of information on/from a magnetic tape by means of this known apparatus the magnetic tape always occupies the same position relative to the magnetic head. In the known apparatus the correct position of the magnetic tape relative to the magnetic head is obtained in that during tape transport the magnetic tape is guided by two tape guides of the magnetic-head unit and one tape edge of the magnetic tape is held in contact with height guides of the magnetic-head unit. This accurately defines the position of the magnetic tape relative to the magnetic-head unit. Since the magnetic head is accurately positioned relative to the height guides in the magnetic-head unit this accurately defines the position of the magnetic tape relative to the magnetic head. When the magnetic head is positioned in the magnetic-head unit the transducing gap of the magnetic head should be adjusted not only in a plane parallel to a plane tangent to the tape guides but also in a direction perpendicular to this tangent plane. A drawback of this is that the positioning means required for this purpose should be movable in many directions and rotatable about many axes, so that intricate and therefore expensive position means are needed. It is an object of the invention to provide an apparatus of the type defined in the opening paragraph in which the magnetic head is positioned more simply relative to the tape guides. The apparatus in accordance with the invention is characterised as defined in Claim 1. By this the position of the magnetic head in a direction perpendicular to the tangent plane to the two guide surfaces is defined, so that positioning means merely have to adjust the magnetic head during manufacturing in a plane parallel to the tangent plane. This enables simpler and hence cheaper positioning means to be used. Furthermore, this defines the angles about an axis parallel to the gap plane and through the transducing gap. Moreover due to the presence of the third mounting surface, the first and the second mounting surface are not interconnected directly, so that connection means, for example an adhesive or welds, does not affect the position of the first mounting surface relative to the second mounting surface. Thus these surfaces are always positioned correctly against one another. It is to be noted that GB-A 2 203 279 discloses a tape recorder of the automatic reversing type which comprises a head mount and a rotatable magnetic head structure including a magnetic head. The head mount has a head insertion hole formed therein, the head mount having a first tapered face formed around a portion of said hole adjacent a tape cassette. The magnetic head structure has a second tapered face formed at a portion thereof near a tape contacting face thereof at which the magnetic head is to contact with a tape of the tape cassette. The magnetic head structure is rotatable around an axis in the head insertion hole with the second tapered face thereof face-contacted with the first tapered face, a spring being provided for urging the magnetic head structure towards the tape cassette to establish a face relationship between said tapered faces. An embodiment of the apparatus in accordance with the invention is characterised in that the mounting surfaces are in contact with one another. The absence of an element, for example a positioning member, between the mounting surfaces enables the head face to be positioned even more accurately relative to the tape guides. An embodiment of the apparatus in accordance with the invention is characterised in that the magnetic-head unit comprises a mounting bracket which is connected to the magnetic head at the location of the third mounting surface and to the front section. An embodiment of the apparatus in accordance with the invention, in which the magnetic-head unit comprises two height guides which are situated at first axial ends of the tape guides and disposed on a connecting line perpendicular to a gap plane through the transducing gap, and in which the magnetic-head unit further comprises two control surfaces situated at second axial ends of the tape guides and adapted to guide one tape edge of the magnetic tape, thereby maintaining the other tape edge in contact with the height guides, wherein the control surfaces also form part of the front section. As the control surfaces bring the magnetic tape into contact with the height guides the magnetic tape occupies always the same position relative to the magnetic head. This means that the control surfaces should always be in contact with the magnetic tape. This is achieved by connecting the control surfaces to the tape guides, so that the control surfaces always occupy the correct position relative to the tape guides and hence relative to the magnetic tape. The magnetic head unit according to the invention is characterized as defined in Claim 5. An embodiment of the magnetic head unit in accordance with the invention is characterised in that the housing comprises a cylindrical section provided with the height guides, and the front section is secured to the cylindrical section. By dividing the housing into a cylindrical section and a front section the housing can be manufactured simply from metal sheet. This is not possible in the case of a one-piece housing. In comparison with, for example, a plastics a metal has the advantage that it is wear-resistant and can provide magnetic shielding. An embodiment of the magnetic head unit in accordance with the invention is characterised in that the cylindrical section comprises a first and a second half, the first half being provided with the height guides and the second half being provided with auxiliary tape guides, and the front section is situated between the height guides and the auxiliary tape guides. If the cylindrical section comprises two halves the height guides and auxiliary tape guides can be accurately and simply spaced from one another by first interposing the front section between the halves and bringing the height guides and auxiliary tape guides into contact with the front section, after which the halves are interconnected, for example by welding. An embodiment of the magnetic head suitable for use in the apparatus in accordance with the invention has two main parts comprising a substrate, which carries a magnetic-head structure in layers, and a counter-block, which is situated on the magnetic-head structure, the first mounting surface being provided on one of the main parts. During the manufacture of the magnetic head both the head face and the mounting surface can be formed in one clamping operation or in one machining operation, for example by means of an accurate grinding operation. This accurately defines the position of the mounting surface relative to the head face, so that in the magnetic-head unit the head face occupies an accurate position relative to the tape guides. The method in accordance with the invention is characterised as defined in Claim 9. The first mounting surface can readily be formed accurately relative to the transducing gaps because both the first mounting surface and the transducing gaps are provided on one and the same element. By connecting this first mounting surface to the second mounting surface of the front section the magnetic head need no longer be adjusted in a direction perpendicular to the mounting surfaces. This simplifies the step of positioning the magnetic head relative to the housing, which enables simpler positioning tools to be used and reduces the time required for positioning, which has lowers costs. This is not possible with conventional magnetic heads because in such heads each transducing gap is formed by two yoke halves placed in an enclosure, which enclosure is subsequently positioned in the housing of the magnetic-head unit. As a result of this, there is no direct relation between the enclosure, on which the first mounting surface may be formed, and the transducing gaps. An embodiment of the method in accordance with the invention is characterised in that the housing, apart from the front section, is formed from two halves of a cylindrical section provided with the height guides and auxiliary tape guides respectively, the front section being interposed between the height guides and auxiliary tape guides of the two halves, after which the two halves are moved towards one another so that the height guides and the auxiliary tape guides make contact with the front section, after which the two halves are connected to one another and the front section is connected to the two halves. When the magnetic-head unit is manufactured in this way the tape guides accurately adjoin the height guides. If the height of the tape guides is smaller than the width of the magnetic tape one edge of the magnetic tape will be in contact with the control surfaces during operation, causing the opposite edge of the magnetic tape to be pressed against the height guides and the magnetic tape to be positioned accurately relative to the magnetic head. An embodiment of the method in accordance with the invention is characterised in that after the height guides and auxiliary tape guides have been brought into contact with the front section a clearance exists between the two halves, and before the two halves are interconnected the halves are positioned relative to one another in a direction parallel to and in a direction perpendicular to the front section in such a way that the height guides and the auxiliary tape guides are aligned with each other. This method and the presence of the clearance between the two halves enables less stringent requirements to be imposed on the dimensioning of the halves, so that these halves can be manufactured simply and cheaply. An embodiment of the method in accordance with the invention is characterised as claimed in Claim 12. By bringing the auxiliary tool into the contact with the mounting bracket at four points, arranged in opposite pairs, the mounting bracket accurately follows the movements of the auxiliary tool and, in addition, pressure can be exerted on the mounting bracket. The pressure promotes a proper contact between the auxiliary tool and the mounting bracket. The mounting bracket cannot move relative to the auxiliary tool, so that the magnetic head can be positioned accurately. The invention will now be described in more detail, by way of example, with reference to the drawings. In the drawings: Figure 1 is a perspective view showing an apparatus with a magnetic-head unit in accordance with the invention and a cassette, Figure 2 is a perspective view of the magnetic-head unit provided with a magnetic head and a housing with a front section, Figure 3 is a front view of the magnetic-head unit, Figure 4 is rear view of the housing, Figure 5a is a side view of the housing, Figure 5b is a plan view of the housing, Figure 6 is a plan view of the cylindrical section, Figure 7a is a front view of the cylindrical section, Figure 7b is a side view of the cylindrical section, Figure 8 is a plan view of the front section, Figure 9a is a front view of the front section, Figure 9b is a side view of the front section, Figure 10a is a front view of an alternative front section, Figure 10b is a side view of the alternative front section, Figure 11 is a perspective of the magnetic head, Figure 12 is a rear view of the magnetic head with a mounting bracket, Figure 13 is a sectional view of the magnetic-head unit provided with the mounting bracket, Figure 14 is a rear view of two other magnetic heads with positioning members, Figure 15 is a sectional view of the magnetic-head unit provided with the other magnetic heads and positioning members, and Figure 16 illustrates the cooperation between the magnetic head and an auxiliary tool for positioning the magnetic head relative to the front section. Figure 1 shows an apparatus 1 suitable for cooperation with a cassette 3 provided with magnetic tape. The apparatus 1 has tape-transport means 5, 7 for transport of the magnetic tape in the longitudinal direction. These tape-transport means comprise capstans 9, 11 and pressure rollers 13, 15 which cooperate with one another. For reading and writing information on the magnetic tape the apparatus 1 comprises a magnetic-head unit 17. This magnetic-head unit 17 is shown in Figure 2. The magnetic-head unit has a housing 18, height guides 21, 23 and auxiliary tape guides 25, 27 forming part of this housing. The housing 18 has a front section 29 provided with tape guides 31, 33 having guide surfaces 35, 37. The front section 29 further has two control surfaces 43, 45 which are inclined relative to the guide surfaces 35, 37. A magnetic head 47, which also forms part of the magnetic-head unit 17, is secured to the front section 29. Preferably, the housing 18 is made of mu-metal, so that the magnetic head 47 is magnetically shielded from the surrounding. The magnetic head 47 has transducing gaps 51 and a head face 49 in which gap ends of the transducing gaps 51 extend, see Figure 3. The height guides 21, 23 are situated at first axial ends 53, 55 of the tape guides 31, 33 and guide a tape edge 72. The two height guides 21, 23 are disposed on an imaginary connecting line 57, which extends perpendicularly to a gap plane 59 through the transducing gaps 51. As a result of this, the gap ends of the transducing gaps 51 always extend perpendicularly to one of the tape-transport directions 61. However, for this the tape edge 72 should be constantly in contact with the height guides 21, 23. In order to achieve this the control surfaces 43, 45 have been provided opposite the height guides 21, 23 at second axial ends 63, 65 of the tape guides 31, 33. The distance 67 between the height guides 21, 23 and the line of intersection between the control surfaces and the guide surfaces 35, 37 is smaller than the width 67 of the magnetic tape 71. This ensures that the other tape edge 73 is always guided by the control surfaces 43, 45. As these control surfaces are inclined relative to the guide surfaces the magnetic tape is subjected to a force directed towards the height guides, causing the tape edge 72 to be pressed against the height guides 21, 23. Figures 4, 5a and 5b show the housing 18. Figure 4 shows a rear view of the housing. The housing 18 has a cylindrical section 19 and is open at the rear, thus enabling the magnetic head to be mounted on the front section via the rear. The front section comprises a mounting surface 75 on which the magnetic head 47 can be arranged with a mounting surface. The mounting surface 75 of the front section 29 extends parallel to a tangent plane 77 to both guide surfaces 35, 37, see Figure 5b. By positioning the magnetic head with a mounting surface relative to the mounting surface 75 of the front section 29 the number of degrees of freedom of the magnetic head is reduced. This results inter alia in the position of the magnetic head 47 in a direction perpendicular to the tangent plane 77 to the two guide surfaces 35, 37 being defined. The position of the magnetic head 47 in a direction perpendicular to the tangent plane 77 is important inter alia in order to obtain a proper contact between the magnetic head and the magnetic tape, which is necessary for a correct signal transfer between the magnetic head and the magnetic tape. Moreover, this defines the angles about an axis through the gap ends and about an axis parallel to the imaginary connecting line 57 perpendicular to the gap plane 59. These angles are also important for a proper contact between the magnetic head and the magnetic tape. In this way, three degrees of freedom of the magnetic head relative to the magnetic-head unit and hence relative to a magnetic tape are defined. The position of the magnetic head 47 in a direction parallel to the longitudinal direction of the magnetic tape need not be adjusted if only the magnetic head 47 is situated between the tape guides 31, 33. This requirement is met because the magnetic head extends through an opening 79 in the centre of the front section between the tape guides 31, 33 (see Figure 4). As a result of this, only the two remaining degrees of freedom of the magnetic head have to be defined. This is achieved by adjusting the distance from the transducing gaps to the tape edge 72 of the magnetic tape and adjusting the angle between the transducing gaps 51 and the longitudinal direction of the magnetic tape. This last-mentioned adjustment is obtained by adjusting the angle between the gap plane 59 to an angle of 90 degrees relative to the imaginary connecting line 57 on which the height guides 21, 23 are situated. Figures 6, 7a and 7b show the cylindrical section 19 of the magnetic-head unit 17. The cylindrical section 19 comprises a first and a second half 83, 85 and is made of a sheet material. The first half 83 comprises the height guides 21, 23 and the second half 85 comprises auxiliary tape guides 25, 27. By first placing the front section 29 between the halves 83, 85 and bringing the height guides 21, 23 and auxiliary tape guides 25, 27 into contact with the front section 29, after which the halves 83, 85 are connected to one another, for example by welding, the height guides 21, 23 and auxiliary tape guides 25, 27 can be spaced from one another accurately and simply. The height guides 21, 23 and the auxiliary tape guides 25, 27 are then spaced at a distance 89 from one another, which distance is equal to the height of a tape guide 31, 33 with a control surface 43, 45. During assembly of the front section 29 with the housing 18 the first axial ends 53, 55 of the tape guides 31, 33 then come into contact with the height guides 21, 23 (see Figure 5a), so that the distance 67 between the height guides 21, 23 and the control surfaces 43, 44 is smaller than the width 69 of the magnetic tape 71 and in operation the tape edge 72 is pressed against the height guides 21, 23. Figures 8, 9a and 9b show the front section 29 of the magnetic-head unit. The front section 29 is made in one piece and is punched from a sheet material, the tape guides 31, 32 and control surfaces 43, 45 being formed at the same time. The front section 29 is connected to edges 95, 97 (see Figure 7a) of the cylindrical section 19 by edge portions 91, 93. Figures 10a and 10b show alternative front section 30 of the magnetic-head unit. This front section 30 also comprises control surfaces 44 and 46, which are situated at one of the ends of the tape guides 32 and 34 and which are curved with radius R. This is in contrast with the control surfaces 43 and 45, which are straight in the view shown in Figures 9a and 9b and which are inclined relative to the tape guides 31 and 33. Figure 11 shows the magnetic head 47 of the magnetic-head unit. The magnetic head 47 has two main parts 101 and 105 formed by a substrate and a counter-block. The substrate 101 carries a magnetic-head structure in layers 103, which structure is covered by the counter-block 105. The substrate 101 and the counter-block 105 have been ground to form the head face 49, in which the gap ends 51 of the transducing gaps extend. The substrate is formed with mounting surface 107 by which the magnetic head 47 can be brought into contact with the mounting surface 75 (see Figure 4) of the front section 29, in order to position the head face 49 relative to the tape guides 31, 33. For this purpose the mounting surface 107 should be formed accurately relative to the head face 49. The substrate 101 has a further mounting surface 109. This surface enables the magnetic head 47 to be secured to the front section 29 via a mounting bracket, so that no adhesive layer is needed between the mounting surfaces 75 and 107 and these mounting surfaces can be accurately in contact with one another. Figures 12 and 13 show how the magnetic head is secured to the front section. The magnetic head 47 is secured to a mounting bracket 115 by the mounting surface 109, for example by means of an adhesive layer. The clearance 116 between the rear of the magnetic head 47 and the mounting bracket 115 is filled with a further adhesive layer. The mounting surface 107 of the magnetic head 47 is subsequently brought into contact with the mounting surface 75 of the front section 29. After this the magnetic head 47 is adjusted in such a way that the imaginary connecting line 57, on which the height guides 21, 23 are situated, extends perpendicularly to the gap plane 59 (see Figure 3). Now the mounting bracket 115 is connected to the front section 29. Before the magnetic head 47 with the mounting bracket 115 is introduced into the housing 18 the magnetic head 47 is connected to a foil 113 provided with electrical conductor tracks. Subsequently, this foil is also attached to the mounting bracket 115, so that the connection between the conductor tracks and the magnetic head is relieved from external forces which may be exerted on the foil 113 when the magnetic-head unit 17 is mounted in the apparatus 1. After the mounting surface 107 of the magnetic head 47 has been brought into contact with the mounting surface 75 of the front section 29 the mounting bracket 115 is first secured to the front section 29 with an end 117. Subsequently, the mounting bracket 115 is secured to the front section 29 with a portion 121 situated near the magnetic head 47. The mounting bracket 115 then draws the magnetic head 47 against the front section 29. By thus securing the mounting bracket to the front section 29 the adhesive joint between the mounting bracket 115 and the mounting surface 109 is only subjected to compressive stress. The connection between the mounting bracket 115 and the front section 29 can be formed, for example, by three welds 125. Figures 14 and 15 show a magnetic-head unit 131 whose housing 133 is identical to that of the magnetic-head unit 17 but whose magnetic head 137, 139 has a different shape. Instead of one head this magnetic-head unit 131 comprises two magnetic heads 137 and 139. In the present case the mounting surface 141, 143 is not situated on the substrate 145, 147 but on the counter-block 149, 151. The magnetic heads 137, 139 are positioned relative to the front section 135 via positioning members 153, 155. The positioning members 153, 155 are then in contact with mounting surfaces 157, 159 on the front section 135 and with the mounting surfaces 141, 143 on the magnetic heads 137, 139. How the position of the magnetic head relative to the front section is adjusted will now be described with reference to Figure 16. After the magnetic head 47 has been connected to the substrate 101 by means of the mounting bracket 115 an auxiliary tool 161 is brought into contact with the mounting bracket 115. The auxiliary tool 161 has two teeth 163, 165 which each comprise a circularly cylindrical wall portion 167, 169. During the cooperation of the auxiliary tool 161 with the mounting bracket 115 the teeth 163, 165 engage in recesses 171, 173 in the mounting bracket, each tooth 163, 165 contacting the mounting bracket 115 with only two points 175, 176, 177, 178 and the magnetic head is pressed with its mounting surface 107 against the front section 29. By rotating the auxiliary tool 161 the angle between the gap plane 59 and the imaginary connecting line 57 between the two height guides 21, 23 (see Figure 3) can be adjusted and by translating the auxiliary tool 161 the distance between the transducing gaps 51 and the connecting line 57 (which in operation coincides with the tape edge 72 of the magnetic tape 71) can be adjusted. As a result of these specially chosen shapes of the recesses 171, 173 and of the teeth 163, 165 the contact between the auxiliary tool 161 and the mounting bracket 115 is established at four points 175, 176, 177, 178, so that the magnetic head exactly follows the translation and rotation of the auxiliary tool 161. This auxiliary tool 161 can be used in the same way for the adjustment of the magnetic heads 137, 139 of the magnetic-head unit 131. Although the invention has been described above with reference to the drawings it is to be noted that the invention is not at all limited to the embodiments shown in the drawings. The invention likewise relates to all embodiments deviating from those shown in the drawings within the scope defined by the Claims. For example, the second mounting surface may be a plane containing three points defined by, for example, three projections on the rear of the front section. It is also possible to provide further control surfaces instead of the height guides, the magnetic tape being positioned in a central position between the control surfaces and the further control surfaces during operation of the apparatus, the two edges of the magnetic tape being in contact with control surfaces.

Claims: Apparatus (1) suitable for cooperation with a cassette (3) provided with a magnetic tape, which apparatus comprises tape-transport means (5, 7) for transport of the magnetic tape in its longitudinal direction, and a magnetic-head unit (17; 131), which unit comprises a housing (18) holding a magnetic head (47; 137, 139) for reading and/or writing information on magnetic tape, which head has a head face (49) towards the tape, if present, and which head face has a transducing gap (51) terminating in the head face and defining a gap plane (59) which is at least substantially perpendicular to the head face, and which unit comprises a pair of tape guides (31, 33), each guide located at a respective opposing lateral side of the transducing gap and including a guide surface (35, 37) for engaging a major side of the magnetic tape, which guides define a tangent plane (77) connecting the guide surfaces, the magnetic head being mounted in the housing with a first mounting surface (107; 141, 143) and a third mounting surface (109), the housing (18) comprising a front section (29; 135) adjacent the head face (49), which section includes both the tape guides (31, 33) and a second mounting surface (75; 157, 159), the second mounting surface being provided at that side of the front section that is opposite to the tape guides and being parallel to the tangent plane (77), the first mounting surface (107; 141, 143) extending at least substantially perpendicular to the gap plane (59), being provided at that side of the magnetic head that is provided with the head face and being parallel to and cooperating with the second mounting surface (75; 157, 159) of the housing, the third mounting surface (109) extending at least substantially perpendicularly to the first mounting surface (107) and being connected to a mounting face of the magnetic head unit. An apparatus as claimed in Claim 1, characterised in that the mounting surfaces (75, 107) are in contact with one another. An apparatus as claimed in Claim 1 or 2, characterised in that magnetic-head unit (17) comprises a mounting bracket (115) which is connected to the magnetic head (47) at the location of the third mounting surface (109) and to the front section (29). An apparatus as claimed in Claim 1, 2 or 3, in which the magnetic-head unit (17) comprises two height guides (21, 23) which are situated at first axial ends (53, 55) of the tape guides (31, 33) and disposed on a connecting line (57) perpendicular to a gap plane (59) through the transducing gap (51), and in which the magnetic-head unit (17) further comprises two control surfaces (43, 45) situated at second axial ends (63, 65) of the tape guides (31, 33) and adapted to guide one tape edge (73) of the magnetic tape, thereby maintaining the other tape edge (72) in contact with the height guides (21, 23), wherein the control surfaces (43, 45) also form part of the front section (29; 135). A magnetic head unit suitable for use in an apparatus as claimed in Claim 1, 2, 3, or 4, which unit comprises a housing (18) holding a magnetic head (47; 137, 139) for reading and/or writing information on magnetic tape, which head has a head face (49) for cooperation with a magnetic tape, and which head face has a transducing gap (51) terminating in the head face and defining a gap plane (59) which is at least substantially perpendicular to the head face, and which unit comprises a pair of tape guides (31, 33), each guide located at a respective opposing lateral side of the transducing gap and including a guide surface (35, 37) for engaging a major side of a magnetic tape, which guides define a tangent plane (77) connecting the guide surfaces, the magnetic head being mounted in the housing with a first mounting surface (107; 141, 143) and a third mounting surface (109), the housing (18) comprising a front section (29; 135) adjacent the head face (49), which section includes both the tape guides (31, 33) and a second mounting surface (75; 157, 159), the second mounting surface being provided at that side of the front section that is opposite to the tape guides and being parallel to the tangent plane (77), the first mounting surface (107; 141, 143) extending at least substantially perpendicular to the gap plane (59), being provided at that side of the magnetic head that is provided with the head face and being parallel to and cooperating with the second mounting surface (75; 157, 159) of the housing, the third mounting surface extending at least substantially perpendicularly to the first mounting surface (107) and cooperating with a mounting face of the unit. A magnetic-head unit as claimed in Claim 5, characterised in that the housing comprises a front section (29; 135) of which tape guides (31, 33) form part and which housing has a second mounting surface (75; 157, 159) parallel to a tangent plane (77) to guide surfaces (35, 37) provided on the tape guides. A magnetic-head unit as claimed in Claim 6, characterised in that the housing (18) comprises a cylindrical section (19, 133) provided with the height guides (21, 23), and the front section (29) is secured to the cylindrical section (19, 133). A magnetic-head unit as claimed in Claim 7, characterised in that the cylindrical section (19) comprises a first and a second half (83, 85), the first half (83) being provided with the height guides (21, 23) and the second half (85) being provided with auxiliary tape guides (25, 27), and the front section (29) is situated between the height guides (21, 23) and the auxiliary tape guides (25, 27). A method of manufacturing a magnetic-head unit (17; 131) comprising a housing (18) and a magnetic head (47; 137, 139), which method comprises the following steps: manufacturing the magnetic head (47; 137, 139) provided with a head face (49) for cooperation with a magnetic tape, and which head face has a transducing gap (51) terminating in the head face and defining a gap plane (59) which is at least substantially perpendicular to the head face and with a first mounting surface (107; 141, 143), a third mounting surface (109), wherein the first mounting surface (107; 141, 143) is formed such that it extends at least substantially perpendicularly to the gap plane (59) and being provided at that side of the magnetic head that is provided with the head face and the third mounting surface (109) is formed such that it extends at least substantially parallel to the gap plane and wherein the head face (49) is obtained in a subsequent operation in which the head face is formed accurately in relation to the first mounting surface (107; 141, 143), manufacturing the housing (18) provided with a second mounting face (75; 157, 159), tape guides (31, 33) and height guides (21, 23), wherein the housing (18) is provided with a front section (29; 135) comprising the tape guides 9341, 33) and the second mounting surface (75; 157, 159), which front section (29; 135) is manufactured in one step in which the second mounting surface (75; 157, 159) parallel to a tangent plane (77) to the tape guides (31, 33) is formed, the second mounting surface being provided at that side of the front section that is opposite to the tape guides positioning the magnetic head (47; 137, 139) in the housing (18), causing the gap plane (59) through the transducing gap (51) to be oriented perpendicularly to a connecting line (57) between the height guides (21, 23), wherein the first mounting surface (107; 141, 143) of the magnetic head (47; 137, 139) is brought into a position parallel to and cooperating with the second mounting surface (75; 157, 159) provided on the housing (18), and affixing the magnetic head (47; 137, 139) in the housing (18), wherein the third mounting surface is secured to a mounting face of the unit. A method as claimed in Claim 9, characterised in that the housing (18), apart from the front section (29; 135), is formed from two halves (83, 85) of a cylindrical section (19) provided with the height guides (21, 23) and auxiliary tape guides (25, 27) respectively, the front section (29; 135) being interposed between the height guides (21, 23) and auxiliary tape guides (25, 27) of the two halves (83, 85), after which the two halves are moved towards one another so that the height guides and the auxiliary tape guides make contact with the front section, after which the two halves are connected to one another and the front section is connected to the two halves. A method as claimed in Claim 10, characterised in that after the height guides (21, 23) and auxiliary tape guides (25, 27) have been brought into contact with the front section a clearance exists between the two halves (83, 85), and before the two halves (83, 85) are interconnected the halves are positioned relative to one another in a direction parallel to and in a direction perpendicular to the front section (29; 135) in such a way that the height guides (21, 23) and the auxiliary tape guides (25, 27) are aligned with each other. A method as claimed in Claim 10 or 11, characterised in that the magnetic head unit is provided with a mounting bracket (115; 153, 155) provided with the mounting face, the magnetic head is positioned in the housing (19; 133) by means of an auxiliary tool (161), and the auxiliary tool comprises two teeth (163, 165) which engage in recesses (171, 173) in the mounting bracket, each tooth of the auxiliary tool being in contact with the mounting bracket at two points (175, 176, 177, 178).

Inventors: VOLLMANN NORBERT CHRISTIAN, VOLLMANN, NORBERT CHRISTIAN
Applicants: KONINKL PHILIPS ELECTRONICS NV, KONINKLIJKE PHILIPS ELECTRONICS N.V.
Application year: 1992
Main classification: G11B5
IPC codes: G11B15, G11B5