US2313126A

US2313126A - Tone arm

Info

Publication number: US2313126A
Application number: US374964A
Authority: US
Inventors: Dally Roy
Original assignee: Webster Electric Co Inc
Current assignee: Webster Electric Co Inc
Priority date: 1941-01-18
Filing date: 1941-01-18
Publication date: 1943-03-09
Anticipated expiration: 1960-03-09

Description

March 9, 1943.

R. DALLY TONE ARM Filed Jan. 18, 1941 3 Sheets-Sheet 1 A QW WN m.

.3 Sheets-Sheet .2

R.- DALLY TONE ARM Filed Jan. 18, 1941 mvlm.

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R. DALLY March 9, 1943.

TONE ARM Filed Jan. 18. 1941 5 Sheets-Sheet 3 mur ///7 AI I* 9;

. j zodezz/Zaf 20g e, a g (J l Patented Mar. 9, 1943 TONE ABM Roy Daily, Racine, Wis., assignor to Webster Electric Company, Racine, Wis., a corporation of Delaware Application January 18, 1941, Serial No. 374,964

7 Claims.

The present invention relates to tone arms and is particularly concerned with tone arms of the type having a crystal reproducer.

One of the objects of the invention is the provision of an improved tone arm construction in which a number of the parts of the assembly, and in particular parts of the reproducer unit, may be eliminated.

Another object of the invention is the provision of an improved tone arm construction adapted to be used for sound reproducing apparatus of high fidelity and which is adapted to be used with conventional phonographs to give the best reproduction and minimum record wear and to eliminate undesirable frequency responses.

Another object of the invention is the provision of an improved light tone arm and reproducer unit structure in which the characteristics of inertia and weight may be conveniently adjusted to any desired value.

Another object of the invention is the provision of an improved form of tone arm pivotal support by means of which the tone arm may be so mounted that it can be lifted up when installed on the phonograph to such position that the bottom of the pickup can be inspected and the needle most conveniently inserted.

Another object of the invention is the provision of an improved tone arm support having a resilient connection between the tone arm and support so that the tone arm can be removed at any time by merely springing apart the pintle supporting springs which are carried by the tone arm support and by means of which any wear may be taken up so that there is no possibility of rattling.

Another object of the invention is the provision of an improved tone arm and reproducer unit which may be manufactured more economically than the devices of the prior art, which may be assembled with less labor, and which requires a lesser number of parts.

Another object of the invention is the provision of an improved tone arm and reproducer unit which is so constructed that the chuck is protected against axial jars which might otherwise break the crystal.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings in which similar characters of reference indicate the same parts throughout the several views.

Referring to the drawings accompanying this specification, of which there are three sheets:

Fig. 1 is a top plan view of a tone arm and turntable installation embodying the present invention;

Fig. 2 is a full size bottom plan View of the tone arm removed from its pivotal support;

Fig. 3 is an enlarged sectional view taken on the plane of the line 3-3 of Fig. 2 looking in the direction of the arrows;

Fig. 4 is a fragmentary vertical sectional view taken on the plane of the line 4-4 of Fig. 1 looking in the direction of the arrows;

Fig. 5 is a fragmentary horizontal sectional view taken on the plane of the line 5-5 of Fig. 4 looking in the direction of the arrows;

Fig. 6 is a fragmentary sectional view taken on the plane of the line 6-6 of Fig. 4 looking in the direction of the arrows; Y

Fig. 7 is a similar view taken on the plane of the line 1--1 of Fig. 4 looking in the direction of the arrows;

Fig. 8 is a similar view taken on the plane of the line 8-8 of Fig. 4 looking in the direction of the arrows;

Fig. 9 is a similar view taken on the plane of the line 9-9 of Fig. 4 looking in the direction of the arrows;

Fig. 10 is a vertical sectional view taken on the plane of the line lll-I0 of Fig. 1 looking in the direction of the arrows, showing details of structure of the means for supporting the tone arm in its inoperative position;

Fig. 11 is a fragmentary bottom plan view of the reproducer end of the tone arm showing the details of structure of this part of the arm;

Fig. 12 is a fragmentary vertical sectional view of the opposite end of the tone arm showing the structure of a pivotal support for the tone arm; and

Fig. 13 is a fragmentary horizontal sectional view taken on the plane of the line i3-I3 of Fig. 12 looking in the direction of the arrows.

Referring to Fig. 1, 20 indicates the fixed support for the tonearm 2| and the turntable 22 in the form of the top panel of a phonograph or other housing. The tone arm, which is indicated in its entirety by the numeral 2i, includes a pivotal supporting member 23 by means of which the tone arm is mounted for substantially universal movement so that it can be lifted from the record and so that it can progress across the record as its needle follows the groove in the record 24.

The tone arm is preferably of a channeled construction having an upper wall 25 (Fig. 6) and a pair of depending

side walls

26 and 21 joined by the partially cylindrical corner portions 28. At its rear or pivotally supported end, it has an end wall 29, closing the end of the channel and joined to the top wall 25 by a partially cylindrical portion 38.

The width of the top wall and of the channeled arm preferably increases somewhat from its rear end toward the free or reproducer end and the channel preferably has an enlargement at its reproducer end, as shown in' Fig. 5. At this end the side. wall 21 is integrally joined to a side wall portion 3| which extends outward at an angle and is joined to a side wall portion 32 which extends diagonally down toward the other end wall 33 of the channeled arm. The side wall 26 may extend in substantially the same direction throughout its full length to the point where it joins the end wall 33.

All of these side wall portions are Joined to their respective end wall or other side wall portions by the

curved corner walls

34, 35, 36, as indicated in Fig. 11, and the walls of the enlargement, which is indicated in its entirety by the numeral 31, are preferably slightly deeper than the rest of the tone arm so that the enlargement forms a housing 38 which` is of greater depth than that portion of the arm which extends backward from it.

The enlargement 31 may be provided on its side walls and top wall 38 with a plurality of transversely extending reenforcing ribs 40 (Fig. 1) extending from the bottom of each wall up over the top of the arm and down the other side.

The inside of the top wall 25 is preferably formed with a pair of longitudinally extending flanges or ribs 4|, 42 (Fig. 2) spaced sumciently to form a groove which will frictionally retain the

conductors

43, 44 leading from the reproducer to the

connectors

45, 46. These connectors comprise strips of metal having a head 41 formed at one end and having a body provided with an aperture for receiving a screw bolt 48 which passes through the aperture and is threaded into a lug that is integral with the tone arm.

The other end of each connector, shown at 49, may be of substantially T shape so that its oppositely projecting flanges may be bent about the wire of the

insulated conductors

43 or 44 to which they are soldered.

The tone arm may have another integral inwardly projecting cylindrical lug 50 provided with a threaded aperture for receiving a bolt which will clamp to the arm a supporting member for the conductors that will be connected to the

connectors

45, 46. This latter conductor will pass along the tone arm and down through the aperture in the supporting post (Fig. 12) to the electrical circuits which are disposed below the supporting table 20.

The tone arm is preferably provided with a plurality of reenforcing ribs, such as the ribs 52 (Fig. 2), 53, 54 and 55, and at its free end the tone arm is preferably provided with an inwardly projecting cylindrical Wall 56 forming a tapered cylindrical socket 51 for receiving a metal body 58 preferably of lead or similar material having a predetermined amount of inertia. The lead body 58 is of substantially the same size as the socket 51 and is secured in place by driving it into the socket and spreading it slightly by impact with a tool. It is retained by friction.

The

ribs

53, 54 previously mentioned are located at the supported end of the tone arm and they provide the

walls

26 and 21 with sulcient body so that bearing

apertures

58, 66 may be of greater length. At its free end, the tone arm is preferably provided with a handle 6| and this handle may take the form of a cast metal member having a supporting portion 62 and a nger piece 63.

The supporting portion comprises a body which is formed on its opposite sides with the

parallel grooves

64, 65 of substantially rectangular cross-section. These grooves are wide enough to receive the end wall 33 between the walls of the grooves and the end wall is preferably provided with an upwardly extending slot 66 open at the bottom so that the supporting portion 62 of the handle may be slid upward into the slot 66.

The width of the slot is substantially equal to the width of the body portion 62 between the

grooves

64 and 65 and the depth of the slot 66 is equal to the depth of the body portion 62 at this point. 'I'he slot 66 is tapered and rounded at the top and it receives the body portion 62 with a frictional fit of sulcient tightness so that the handle is retained by the tone arm.

The finger portion 63 extends longitudinally outward from the body portion 62 as shown in Fig. 4 and has its lower part provided with a concave surface 61 for engagement with a finger. Its upper side may have a similar curvature.

In addition to serving as a support for the handle, the groove 66 also provides access to the needle-clamping screw 68 (Fig. '7) which is preferably made of the type having a threaded shank and a head with a cruciform socket 69 that requires a special type of tool which the ordinary user may not have so that he will not tamper with the tone arm.

The tone arm is preferably constructed of cast or molded material. It may be cast of various types of light metals, such as aluminum, or aluminum alloys, but is preferably made of a molded insulating material such as a phenolic condensation compound or some other form of molding .powder such as that called Bakelite."

All of the parts of the tone arm so far described, except the conductors and connectors, handle and weight, are of one integral piece, so that they may be manufactured economically and require no labor in assembly. Such a tone arm made of insulating molded material is very light and when used with the iiexible type of needle such as that shown at 10 (Fig. 6), might result in movement or vibration of the complete tone arm by the needle instead of producing the desired effect on the crystal of the reproducer.

Therefore, the relatively light tone arm is provided with the inertia mass previously described and indicated at 58 which has suiiicient inertia so that the tone arm has the proper inertia characteristics. This mass also gives the tone arm suicient weight at its free end and concentrates the weight at the desired point so that the needle will track properly in the record groove.

Referring to Fig. 11, this is a bottom plan view of the free end of the molded tone arm channel which is provided with integral formations suitable for the support of the crystal and other elements of the reproducer which forms a part of the tone arm. In this case one of the clamping members or housing members for the reproducer forms an integral part of the tone arm.

The reproducer housing is preferably of a type somewhat similar. to that disclosed in my prior application Serial No. 338,519 filed June 3, 1940, for Crystal pick-up units. One of the half-housing members disclosed in that application is prefv has.

erebly employed witnthe tone. arm structure in y this embodiment of the invention.

Thus, the chamber 880i' the toneis-'pref-- erably provided with a pair of inwardly project-l ing parallel ribs or walls 1|, 12 which projectfrom 44 and to clamp the insulated portion of these conductors in such manner that it will be held in fixed position.

spaced inwardly of the end w'all 13 there is a transversely extending rib 11 in the reproducer chamber 18 having an upper plane surface which is located below the upper surface of walls 1| and 12 when the walls are viewed as seen in Fig. l1 in the inverted position. The rib 11 serves to support a resilient block 18 which may be made of soft resilient rubber or printers roll composition or other material -of similar resilient characteristics.

Referring again to Fig. ll, the end wall 14 is provided with a transversely extending half cylindrical groove 80 for passing a portion of the chuck which has the threaded bore for receiving the clamping screw 88. The walls 1|-14 of 'that portion of the reproducer housing which is integral with the tone arm are preferably suitably enlarged at the points where the' threaded bores 8| are located, as these threaded bores are used in connection with the screws for clamping the other half housing to the tone arm.

The molded tone arm also has inside the crystal I chamber 1I an inwardly extending integral bearing lug 88 whichmay be of substantially rectangular external/outline but which is provided with a half oylmxrioai groove u and with misto conical tapered portions '85, 86 leading to the groove 94.

Referring now to Fig. 4, 90indicates in its entirety the other half-housing member which cooperates with the walls of chamber 18 in the tone arm to complete the chamber for the crystal of the reproducer. 'I'his half-housing member 90 is in fact practically similar to the construction of one of the half-housing members of my prior application above mentioned and it may comprise a metal stamping made of suitable sheet metal such as aluminum or an aluminum alloy.

This half-housing member is provided with a border ange, the side portions of which are shown in Fig. 6 at 9| and 92 as relatively narrow ilanges, and the end portions of which are shown in Fig. 4 at 93 and in Fig.y '1 at 94, 95. The hous-- ing member 90 comprises a sheet metal member which is recessed inside the border anges 9|-95 and it thus forms a part of 'the chamber within which the crystal and chuck of the` reproducer are housed. Its 'border flanges 9 |-95 are adapted to engage the at or plane surface indicated at 98 on theside and end walls 'I I-14 of the chamber 18 in the tone arm enlargement 81 to form a substantially closed housing.

Certain of these border flange portions, however, are provided with'recesses as follows: Referring to Fig. 7 between .

theborder flange portions

94, 95 there is a partially cylindrical pressed groove 91 which registers with the-partially cylindrical groove 80 of Fig. 11 to form a cylindrical bore for receiving one o f the trunnions 88 of the chuck which is indicated in its entirety by the numeral |00. 4

groove and surfaces substantially like those 'indicated at 84, 88, 88 in Fig. 11.

When the two

housing portions

18 and 80 are placed together. these grooves y84 register and form a cylindrical bearing supporting bore for the right-hand trunnion |08 of the chuck |00. The sheet metal half-housing 90 is also provided with an inwardly extending rib |09 (Fig. 4) having a plane upper surface ||0 which may extend fully across the half-housing 90. 'I'his surface is intended to support a resilient block similar to that previously described for clamping the crystal members in i'lxed /position in the housing as shown in Fis. 4. o

The size of the blocks 19, ill and the ridges |08 and 11 relative to the thickness of the crystals and the space in the housing are such that the blocks 19, are compressed and the crystals resillently clamped by the housings when the parts are assembled as shown in Fig. 4. To secure the housings together, the sheet metal member 90 is provided with apertures registering with the apertures 8| at the ends of the housing 18 and screws pass through apertures in the halfhousing 90 and are threaded into the bores I8| to secure these two housing members together.

The chuck |00 comprises a cast metal member which may be made of any suitable metal such as die cast metal having a cylindrical trunnion 98 on one side of its central body I2 and another trunnion |08 on the other side of the central body ||2. These bearing portions are aligned, being generated on the same axis and the trunnion |08 is preferably bordered by the frusto-conical thrust surfaces H3, ||4.

Thus, a tubular sleeve ||8 of live resilient material, such as rubber, may be' placed on the trunnion |08, also covering the frusto-conical surfaces I3, ||4, and the asseinbLv, including the sleeve, will be of a suitable shape to be com' plementary to the aperture formed by the grooves 84 and |05 and the frusta-conical surfaces 85,

86 and |06, |01 in the half-housing members.

Here again the live rubber sleeve H5 is slightly larger than the space which it is to occupy so y A ings H3, ||4 and truste-conical surfaces 85, 86,

The trunnion 98 may be substantially cylindrical and it isprovided with a live resilient rubber sleeve H6 which engages the

cylindrical grooves

80 and 91 in the housings and prevents metal-tometal contact between the chuck and the housing at this point.

This sleeve is also initially compressed when the housings are secured together, as will be evident from the fact that the compressed portion is smaller at the left-hand end of the sleeve in Fig. 5. The trunnion 88 is provided with anax- The sheet-'metal rnent-housing 'member u is l also formed with an inwardly pressed formation III between its ends and at the right of the chuck ially extending bore I|1 which is threaded to receive the threaded shank of the clamping screw 33. This screw shank is long enough to extend through the bore ||1 into engagement with a needle 1l which is mounted in a communicating borelllinthebodylll v The main body ||2 of the chuck |00 may comprise a substantially cylindrical diagonally outward and downwardly extending portion ||2 having the bore ||3 which is open at the bottom and which communicates with the bore I|1.at the top.

The needle 13 is preferably of the type havingk a cylindrical upper shank ||3 which has a fiattened surface |23 for engagement with the shank of the bolt 43. The needle has this surface in order that it may be disposed in proper rotative position as it also has a pair of concave depressions |2| at the opposite sides of the needle be'- tween'its point and the cylindrical shank III in the bore ||3.

These concave depressions |2| give the needle an intermediate resilient portion which i'lexes or bends more easily in a plane passing through the axis ofy the needle and extending at right angles to the tangent to the groove of the record.

It will be noted in Fig. 5 that the housing half which is integral with the tone arm is disposed at an angle to the major axis of the tone arm and this is for the purpose of bringing the needle into proper position for approximate tangential tracking with respect to the spiral grooves of the record.

The chuck has at its' end opposite to the trunnion 33, a substantially U-shaped formation comprising the two ilanges |22, |23. These flanges have the plane clamping surfaces |24 and are provided with a clearance at |25over the rest of the surface between the flanges |22 and |23.

The uppermost flange |22 also has its upper plane surface |23 engaging a live rubber block |23 which engages the top wall 25 of the tone arm.- 'I'his block |23 may consist of live resilient rubber or printer's roll composition or other suitable resilient material and it is included for the purpose of giving the chuck and crystal assembly and tone arm the desired resilient and frequency characteristics.

The crystal assembly |25 may comprise a pair of suitable crystals such as Rochelle salts adapted to generate' an electromotive force when subjected to torsion. I'he crystal assembly may consist of a pair of crystals |30, |3I separated by a layer of metal foil |32 which is connected to one of the conductors, such as conductor 43, by a foil strip |33 and a drop of solder |34.

The two crystals |30 are connected over all by a covering of foil, the upper layer of which is indicated at |35 and Vthe, lower layer at |36, both 70' layers being insulated from the centrally located foil |32 vby the crystals |30 and |3|, and the outer layer may extend over both edges and sides completely enclosing the crystals and protecting them frommoisture.

As the crystal members in this pickup are disposed in a plane parallel to the plane of the record. they will'of course be cut appropriately with respect -to the axes of the crystal from which they are made, so that the twisting action of the chuck under the influence of the needle' will generate electromotive forces that are collected by means of the foil |32, |35, |36, and carried to the

conductors

43 and 44 by the strips of foil |33, |31.

vThe units may be provided with

conductors

43, 44 which lead to

connectors

45, 46 or with conductors of any desired length extending the full length of the tone arm and down through the support Il,

Referring to Figs. 12 and 13. the rear end of the tone arm is supported upon the column 5 which comprises a tubular member having a through bore |33 having its upper end formed with a relatively narrow thrust surface |33. 'I'his narrow thrust surface is provided by making the end portion |40 of the bore |30 frusto-conical and by providing a taper |4| at the upper outer surface of the cylindrical column 5|.

At its lower end this column has a reduced'- threaded portion |42 and there is an annular shoulder |43 which engages a stamped sheet metal collar |44. The collar |44 has a centrally located bore |45 for passing the reduced 4threaded portion |42 and it comprises a flange which extends downwardly and radially so that its lower and outer edge |45 is adapted to rest on the phonograph table 20. v

A very light spring washer of the wavy type is preferably interposed between flange |53 and thrust bearing surface |39 to prevent any rattling. I'he lower end of the tube |50 is provided with a half cylindrical groove |54 extending com- 5 pletely around the tube and adapted to receive a round spring wire |55 which is bent to substantially circular form and which exerts a clamping action that retains it in the groove |54.

'I'he spring |64 comprises a strip of spring steel bent to substantially U shape and having its yoke |65 provided with the aperture for receiving the rivet |62. The two legs |66, |61 of this spring extend in the same general direction but may diverge slightly as shown in Fig. 13 and at their ends they are provided with apertures for receiving the riveted studs |66 which are similar in.

shape but opposltely disposed.

This reduced cylindrical portion |12 ts in the bearing apertures 59 and 60 of the tone arm while the frusto-conical portion |1| bears against the end portion of the apertures 59 or 60 and under the resilient compression of the spring arms |66, |61, any wear which occurs in the bearing is taken up and rattling is positively prevented.

The tone arm is thus pivotally supported on the post at an axis which is disposed very close to the rear wall 29 and the flange |51 is of suilicient length so that as the tone arm pivots upward, the rear wall 29 may pivot down into the space which appears between the tone arm in Fig. l2 and the flange |53.

Referring now to Figs. 1 and 10, the tone arm is preferably provided with an auxiliary support for holding it and protecting the needle and reproducer against damage when it is not being used on a record. This support is indicated in Fig. 1 at |13. This support preferably comprises a tubular metal column |14 having an enlarged bottom portion |15 provided with a at lower surface |16 which engages the table 20.

The upper end of the smaller portion of the tube |14 may be engaged by a cylindrical rubber block |11 of such diameter that it has to be compressed when it is inserted between the depending

flanges

26 and 21 of the tone arm. 'This rubber member |11 preferably has its upper corners rounded at |6| so as to give the block a kind of taper which will permit it to be compressed as it slides ln between the anges 26 and 21.

The rubber block has it central bore .|16 tapered at |19 to receive the head of a screw bolt |60 which passes through the rubber cushion |11 and the column |14 and secures the rubber tothe column and the column to the table 20 by means of a nut on its lower threaded end, the bolt passing through the table.

The size of the rubber member |11 is such that when the tone arm is pushed on it as shown in Fig. 10, the tone arm is retained against removal by friction, but it may be pulled oi! by application of a predetermined vertical force whenever it is desired to lift the tone arm and place it on a record.

The tone arm may be removed from the column 5| at any time by compressing the spring legs |61, |66, sufilciently to remove the trunnions |12 from their bearings 59 and 60. The tone arm is insulated by the rubber at |59 from needle noise or other undesirable noises which mightl be transmitted to the tone ann by the column.

The characteristics of the tone arm and reproducer are greatly improved over the devices of the prior art. There is less needle wear due to the lightness of the ytone arm, and the inertia characteristics of the tone arm may be adjusted to vany desired value.

By locating the handle 62 and the weight 58 near the free end of the tone arm, its mass is concentrated near the crystal pickup unit and made most effective, and the tone arm may be made much lighter than if the same mass were distributed throughout the full length of the tone arm.

The present tone arm may be manufactured at a very low cost because of the reduction in the number of its parts, and it may be assembled more quickly than the devices of the prior art in which the reproducer is a separate unitbefore it is placed in the tone arm. The crystals are protected against moisture by being completely enclosed in tin foil and they are protected against breakage by the thrust bearing arrangement which is located just behind the needle.

A thin resilient needle may be employed and the operator is deterred from tampering with it because ofthe fact that the needle clamping screw is concealed by the handle and a special clamping screw is used for which a special tool should be employed.

While I have illustrated a preferred embodiment of my invention, many modications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but de- Y sire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desired to secure by Letters Patent of the United States, is:

1. In a crystal reproducing member, the combination of a. tone arm having a recess formed in its free end and having a half-housing formed in said recess for enclosing a crystal unit and a chunk, a. second half-housing memberv adapted to engage the housing formed in said tone arm, means .for securing said housing members together, a crystal unit carried by said housing members, and a needle chuck movably mounted between said housing members and engaging said. crystal unit, said tone arm being constructed of molded insulating material and said other half-housing member being a stamped sheet metal member.

2. In a crystal reproducing member, the combination of a tone arm having a recess formed in its free end and having a half-housing formed in said recess for enclosing a crystal unit and a chuck, a second half-housing member adapted to engage the housing formed in said tone arm, means for securing said housing members together, a crystal unit carried by said housing members, and a needle chuck movably mounted between said housing members and engaging said crystal unit, said tone arm being constructed of molded insulating material and said other halfhousing member being a stamped sheet metal member, and said means for securing comprising threaded screw bolts passing through apertures in said sheet metal member and threaded into threaded bores in said tone arm.

3. In a reproducer unit the combination of a housing member of a molded phenolic condensation compound formed with projecting side flanges defining the walls of the housing, said side flanges being provided with threaded bores, end flanges on said housing, one of said end flanges having an enlarged aperture for clearance around the chuck and the other of said end flanges having grooves formed therein for partial reception of rubber-covered conductors and said latter end flange having a threaded bore, said housing being formed on 'its interior with a raised surface for engaging a crystal and having spaced from said surface a projecting lug provided with a half cylindrical 4bearing surface and with tapered thrust surfaces on both sides, a metal housing member comprising a stamped sheet metal member formed with an outwardly projecting border flange adapted to engage the side walls of the, first-mentioned housing, said lateral member having a pressed formation for engaging the crystal vand another pressed formation provided with thrust surfaces and a half cylindrical bearing surface, a crystal clamped between said housing members and a chuck engaging said crystal .and having a trunnion, said trunnion having thrust surfaces at its ends and a resilient covering for said trunnion and thrust surfaces whereby the trunnion and thrust surfaces may be clamped Ibetween the housing members to secure it for a limited universal movement.

4. In a reproducer unit the combination of a housing member of a molded phenolic condensation compound formed with projecting side flanges defining the walls of the housing, said side flanges being provided with threaded bores, end flanges on said housing, one of said end flanges having an enlarged aperture for clearance around the chuck and the other of said end flanges having grooves formed therein for partial reception of rubber-covered conductors and said latter end flange having a threaded bore, said housing being formed on its interior`with a raised surface for engaging a crystal and having spaced from said surface a projecting lug provided with a half cylindrical ybearing surface and with tapered thrust surfaces on both sides, a` metal housing member comprising a stamped sheet metal member formed with an outwardly projecting border flange adapted to engage the side walls of the first-mentioned housing, said lateral member having a pressed formation for engaging the crystal and another pressed formation provided with thrust surfaces and a half cylindrical bearing surface, a crystal clamped between said housing members and a chuck engaging said crystal and having a trunnion, said trunnion having thrust surfaces at its ends and a resilient covering for said trunnion and thrust surfaces whereby the trunnion and thrust surfaces may be clamped between the housing members to secure it for a limited universal movement, and threaded members passing through said sheet metal member and threaded into said insulating housing to clamp the chuck, the crystal and the conductors between said housing members.

5. In a combined tone arm and reproducer unit, the combination of a tone arm of molded material having a housing formed in its free end for housing part of a crystal and chuck assembly, a complementary housing member adapted to be combined with the tone arm to complete the enclosure of the crystal and chuck assembly, said housings having half-cylindrical grooves formed at the rear end thereof whereby substantially cylindrical apertures are formed when the housing is assembled, and conductors for effecting connections with said crystal unit comprising insulated electrical conductors covered with live resilient material, the insulation of said conductors being of slightly larger size than said cylindrical aperturesrwhereby the conductors may be clamped between the parts of the housing to anchor them to the housing.

6. In a combined tone arm and reproducer unit, the combination of a tone arm of molded material having a housing formed in its free end for housing part of a crystal and chuck assembly, a complementary housing member adapted to be combined with the tone arm to complete the enclosure of the crystal and chuck assembly, said housings having half-cylindrical grooves formed at the rear end thereof whereby substantially cylindrical apertures are formed when the housing is assembled, and conductors for effecting connections with said crystal unit comprising insulated electrical conductors covered with live resilient material, the insulation of said conductors being of slightly largerv size than said cylindrical apertures whereby the conductors may .be clamped between the parts of the housing to anchor them to the housing, said tone arm being formed on its lower side with a pair of parallel ribs between which said conductors may be compressed and retained by frictional engagement therewith.

7. In a combined tone arm and reproducer unit, the combination of a tone arm of molded material having a housing formed in its free end for housing part of a crystal and chuck assembly, a complementary housing member adapted to be combined with the tone arm to complete the enclosure of the crystal and chuck assembly, said housings having half-cylindrical grooves formed at the rear end thereof whereby substantially cylindrical apertures are formed when the housing is assembled, and conductors for effecting 4:on-

nections with said crystal unitJ comprising insulated electrical conductors covered with live resilient material, the insulation of said conductors .being of slightly larger size than said cylindrical apertures whereby the conductors may be clamped between the parts of the housing to anchor them to the housing, said tone arm being formed on its lower side with a pair of parallel ribs between which said conductors may be compressed and retained -by frictional engagement therewith, and electrical connectors carried by the other ends of said conductors and secured to the lower end of said tone arm.

ROY DALLY.