GB2063548A - Turntable - Google Patents

Abstract

A record player turntable made in two parts comprises an upper part (10) having a record supporting surface (21) and a lower part (11) having a depending peripheral flange (12) and a central boss (13) with an inner metal sleeve (18) which rotates upon the normal upstanding centre post or sleeve on the record player deck plate. The upper part (10) has a central circular opening (22) with flexible legs (23) extending downwardly from the periphery of the opening and having snap-engagement with apertures (19) formed in the enlarged upper part (16) of the central boss (13) so that the two parts (10) and (13) are releasably connected together. In an alternative form, the central boss of the lower part has upwardly extending flexible tongues which have releasable snap-engagement with the periphery of the central hole in the upper part. <IMAGE>

Description

SPECIFICATION Record player turntable This invention relates to turntables for record players and has for its object to provide a new or improved form of turntable which provides certain advantages and benefits (as detailed hereinafter) in the manufacture of turntables, and the assembly of turntables in record players.

One form of drive for a record player turntable is that wherein the turntable is formed on its underside with an integral depending flange which is circular and concentric with the axis of rotation of the turntable and which forms an integral pulley around which a driving belt is engaged to transmit the drive from the driving motor spindle to the turntable.

In another form of drive, the turntable also has on its underside an integral depending flange and in this form the drive is transmitted to the inner surface of this flange by means of a jockey pulley which is itself driven by the driving spindle of the record player driving motor.

The invention is concerned broadly with turntables for record players having either of these forms of drive.

According to the invention we provide a turntable made in two parts, there being an upper part which provides the support for the record and a lower part which includes the aforesaid depending flange and which is adapted for mounting on the record player for rotation about a vertical axis, the two parts being provided with co-operating means to enable the upper part to be engaged nonrotatably with the lower part and there being means for releasably securing the two parts together.

The expressions "upper", "lower" and "vertical" as used herein refer to the disposition of the turntable in its normal operating position with the record support surface in a horizontal plane.

Preferably, the lower part includes a central hollow boss adapted for mounting the turntable rotatably upon the normal fixed centre sleeve on the deck plate of a record player.

Referring to the first mentioned form of drive, when installing a conventional onepiece turntable in a record player the turntable is presented to the normal central bearing sleeve extending vertically from the deck plate of the record player with the driving belt engaged round the turntable integral pulley and then the final operation is to engage the belt around the driving spindle. This means that an opening must be provided through the operative surface of the turntable to enable fingers to be passed through to manipulate the belt and engage it with the driving spindle, and in practice this means the provision of two diametrically opposed openings of the same shape and positioning so as to maintain the balance of the turntable.

At present, some inexpensive turntables are made as mouldings in plastics material and the presence of the aforesaid holes means that a rubber or plastics material mat has to be provided to conceal the holes. The turntable of the present invention, having no such holes, does not require a mat and enables some saving in cost to be effected.

A turntable for a record player having the second mentioned form of drive does not require the holes and therefore a mat is not necessary but during the process of moulding a turntable in plastics material, the presence of the depending flange results in the appearance of a slight circular depression on the upper surface of the turntable immediately above the position of the flange and in order to provide a respectable outward appearance, this circular depression has to be obscured or filled in some way usually with the aid of a trim ring or strip. The present invention avoids this problem.

As discussed hereinafter, the invention may also be applied with advantage to the construction of a metal turntable, for example one made as an aluminium or aluminium alloy die casting.

The invention is illustrated by way of example in the accompanying drawings which show alternative embodiments of the invention.

In the drawings:~ Figure 1 is a section taken vertically through a two-part turntable; Figure 2 is a plan view of the lower part of another form of two-part turntable; Figure 3 is a section on line 3-3 of Fig. 2; and Figure 4 is an enlarged fragmentary section on line 4-4 of Fig. 2.

Referring to the drawing, the turntable shown in Fig. 1 comprises an upper part generally indicated at 10 and a lower part generally indicated at 11, both being formed as mouldings in a suitable plastics material and the lower part 11 having a depending peripheral flange 12 which is connected to a central boss formation 13 by an annular web 14. At its periphery, the web 14 has an upstanding circular rib 15 which is an upward continuation of the flange 12 and is provided for a purpose hereinafter referred to.

The central boss formation 13 has an upper part 16 of enlarged diameter and a lower part 17 and a central axial passage extending through the boss 13 in which is fitted a metal sleeve 18, which may be incorporated as an insert in the moulding of the boss 13 and this sleeve 18 is adapted for rotatable engagement with the normal central upstanding sleeve provided on the record player deck plate. The enlarged upper part 16 of the central boss also has three through passages 19 which are spaced apart at 1 20' around the axis and also three further through passages 20 also spaced apart at 120 around the central axis and in 60" relationship with the through passages 19.

The upper part 10 of the turntable provides a record support surface 21 and a central circular opening 22 and from the periphery of this opening 22 there are three downwardly extending legs 23 spaced apart at 120" around the central axis, each downwardly depending leg having a tapered nose 24 at its lower end providing an upwardly presented shoulder 25. The plastics material is such as to provide a certain degree of flexibility in each leg 23 so that it can be deflected in directions towards and away from the central axis.

At the central opening 22 there is a depending annular flange 26 which locates within the central opening in the upper part 16 of the central boss 13 when the upper part of the turntable is engaged with the lower part. The legs 23 extend downwardly from the flange 26. In assembling the two-part turntable in a record player, the lower part 11 is first engaged with the normal fixed centre sleeve of the record player and in the case of a belt type of drive, the driving belt is engaged around the exterior of the flange 12 and around the normal driving spindle of the record player motor. In the case of a jockey pulley drive, the part 11 is manipulated to engage the jockey pulley with the inner surface of the depending flange 1 2.

Thereafter the upper part 10 is presented downwardly to the lower part 11 and the flexible legs 23 pass through the passages 19, with each leg being deflected outwardly slightly until the nose 24 has passed completely through the passage 19 and the leg can spring back towards the central axis to engage the upwardly presented shoulder 25 with the underside of the part 16 of the central boss. At the same time, the flange 26 engages within the central opening 22. Finally, the assembled turntable may be retained in place in the normal manner by means of a circlip engaging over the upper end of the record player centre sleeve and restraining the sleeve 18 from upwards movement. The complete turntable may be removed from the record player by disengaging the aforesaid circlip and lifting the two part assembly off the centre sleeve of the record player.The top part may then be released from the lower part by deflecting the legs 23 outwardly to enable them to be pulled through the passages 19.

Thus, the turntable may be removed, separated into two parts and subsequently reassembled in the record player any number of times according to the requirements of servicing or replacement of a loose or broken belt.

The legs 23 are dimensioned so that when in the engaged position as shown in the drawing, the leg is under tension urging the central region 26a of the upper part downwardly whereby this central region 26a may flex slightly during assembly and become under tension so that the underside thereof is held in firm engagement with the circular rim 15 on the lower part. This ensures that there is no possibility of "slack" in the assembly of the two parts.

Referring to Figs. 2, 3 and 4, the main difference between this alternative embodiment and the one above described is that in this case the means for releasably securing the two parts together are formed on the lower part of the assembly. This lower part, which is formed as a moulding in plastics material, has the downwardly depending flange 30 and upwardly presented peripheral rim 31 with a dished central portion 32 in which is moulded the metal sleeve 33 for engagement over the fixed centre sleeve or stump of a record player. In the particular form shown, the centre part 32 is also provided with an upwardly projecting centre stub 34 over which may be fitted a short centre spindle. However, in another form the stub 34 may be omitted so that the arrangement is similar to that of Fig. 1.

The vertical wall 35 of the centre dished portion 32 is interrupted at three places around its periphery spaced apart at 1 20' spacings so as to provide three upwardly extending flexible tongues 36. Each tongue 36 is formed by the provision of a pair of spaced parallel slits 37 extending through the wall 35 and at its upper end, each tongue 36 is formed with an outwardly projecting nose 38 having a downwardly presented shoulder 39. The inherent resilience of the plastics material allows each tongue 36 to flex inwardly under pressure and then return to its original position.

In assembling this form of two-part turntable into a record player, the lower part is first engaged over the fixed centre sleeve on the record player and then the upper part 40 which has a plain central opening is presented downwardly towards the lower part and the engagement of the inner periphery of the upper part 40 with the sloping faces on the noses 38, causes the tongues 36 to be deflected inwardly so that the noses 38 can snap over the edge of the central opening in the part 40 to come into engagement as shown in Fig. 4. The remainder of the inner periphery of the upper part 40 locates around the outer surface of the upstanding wall 35 on the lower part.

As with the first described embodiment, the centre region of the upper part 40 is allowed to flex during assembly with the lower part so that it may be put under tension and ensure that the underside of the record supporting surface 41 is held firmly against the upwardly projecting rim 31 on the. lower part.

For a moulded plastics material turntable to be used in a belt drive form of record player, the invention eliminates the necessity for providing openings through the upper surface of the turntable for the fixing of the belt and thus eliminates the need for providing any rubber mat. This can effect an appreaciable saving in the cost of manufacture., With a plastics material turntable to be used wth a record player having a jockey pulley drive, the two-part assembly eliminates any circular depression appearing as a result of the moulding process and thus removes the necessity for making provision to conceal such depression.

The invention may also be applied to an aluminium turntable and in one form, the lower part may be a plastics material moulding as in Fig. 4, with the upper part 40 being formed as a die casting in aluminium. In this form, the invention provides a manufacturer with the advantage of being able to offer interchangeable moulded plastic or aluminium turntables to suit particular customers requirements.

In the case of a wholly aluminium turntable, where both the upper and lower parts are formed as aluminium die castings, separate snap-in type fastener components may be provided for securing the two parts releasably together.

In the arrangement of Fig. 4, where the upper part 40 is formed of aluminium, a rubber or plastics mat may be provided as shown in dotted lines.

A further advantage applicable to turntables being used in record players with either form of drive is that the lower part may be a standard part whilst a number of different forms of upper part may be produced with the record player support surface of different design according to customers' requirements such that a stock of different designed upper parts may be kept and used selectively as required with a standard form of lower part.

Claims (7)

1. A record player turntable made in two parts, there being an upper part which provides the support for the record and a lower part which includes a depending flange of circular form, concentric with the axis of rotation of the turntable, said lower part being adapted for mounting on the record player for rotation about a vertical axis, the two parts being provided with co-operating means to enable the upper part to be engaged nonrotatably with the lower part and there being means for securing the two parts releasably together.

2. A turntable according to Claim 1 wherein the lower part has a central hollow boss and an annular web, at the periphery of which is provided said depending flange and also an upstanding circular rib, the upper part having a central circular opening with a depending annular flange which locates with the upper end of the central boss of the lower part and the underside of the upper part being in engagement with the upper surface of said rib.

3. A turntable according to Claim 2 wherein the upper part of said central boss of the lower turntable part is of enlarged form and has a number of holes extending therethrough which are equiangularly spaced about the central axis and the depending annular flange of the upper turntable part has a number of downwardly extending flexible legs which engage with resilient snap action in said holes when the two turntable parts are assembled together.

4. A turntable according to Claim 1 wherein the lower part has a central hollow boss and the upper turntable part has a central opening which engages around the upper end of said boss, the annular wall of said boss being formed with slots to provide a number of upwardly extending flexible tongues which have snap action engagement with the periphery of said central opening when the two turntable parts are assembled together.

5. A turntable according to Claim 1 wherein the lower part has a central hollow boss and an annular web, at the periphery of which is provided said depending flange and also an upstanding circular rib which is an upwards extension of said flange and the upper turntable part has a central circular opening the periphery of which is located by the upper end of said boss with the underside of the upper turntable part being supported by the upper surface of said rib.

6. A record player turntable substantially as hereinbefore described with reference to and as shown in Fig. 1 of the accompanying drawings.

7. A record player turntable substantially as hereinbefore described with reference to Figs. 2, 3 and 4 of the accompanying drawings.