Patent GB-585090-A (GB)
Title: Improvements in electric record-changing gramophones
IPC: G11B17/02
Filed: 1944-03-15
Abstract: 585,090. Magazine gramophones. OLSSON, G. D. March 15, 1944, No. 4851. [A Specification was laid open to inspection under Sect. 91 of the Acts, Sept. 20, 1944.] [Class 40 (ii)] The pick-up arm in a magazine gramophone is lifted and lowered and swung horizontally from a single electromagnetic clutch which also drives the mechanism for feeding records to the turntable. Pick-up lifting and lowering and traversing. As shown in Figs. 5 and 7, the driving member of the clutch is constituted by an armature 94 having facial teeth 97. The armature is supported on a hollow stub-shaft 85 so as to be capable of upward movement when the electromagnet 101 is energized. The shaft 85 is carried on the motorboard 1 and has one end formed as a worm gear 86 through which the shaft is driven. Within shaft 85 is a sleeve 79 surrounding a lift-rod 63. Sleeve 79 carries at its upper end a gear-wheel 103 for engaging armature 94 having facial teeth 98 and being capable of limited vertical movement. The gear-wheel is normally held in its uppermost position by a spring 107. The lower end of sleeve 79 is formed with a skirtlike flange 80 having a recess 81 and an inner cam 82 of triangular form in plane development disposed opposite the recess, the recess and cam co-operating to constrain a pin 64 passing through rod 63, and rod 63, to move up and down. Pin 64 and rod 63 are prevented from rotating as one end of the pin enters a slot 66 in bracket 61. Rod 64 passes upwardly through the hub 62 of the bracket 68 which carries the pick-up arm 70 pivoted about the horizontal axis 71. The end 76 of the pick-up arm is forked about the hub 62 and is engaged by a cross-pin 78 carried in lift-rod 63 and passing through flared slots in the hub. Vertical movement of the rod 63 thus controls the raising and lowering of the pick-up. The swinging movement of the pick-up arm to move the pickup horizontally is effected by engagement of a pin 75 on a gear-wheel 144 in an extension 73 of the bracket 68, gear-wheel 144 rigidly mounted on a shaft 45 mounted on top-plate 11 and driven by engagement with a gear-wheel 130 which is formed on a sleeve 124 surrounding a depending portion of the hub 62. The lower end of sleeve 124 extends over the upper end of a sleeve 108, the two sleeves being constrained to rotate together and the lower sleeve being constrained to move vertically with the lift-rod. Sleeve 108 has a flange 109 at its lower end provided with spring-pressed teeth 99 for engaging teeth 97 on armature 94. Surrounding sleeve 108 is a further sleeve 116 which is urged downwardly by a spring 129 and has two pins 119 extending from its base through holes 120 in the flange 109, pins 119 butting on the upper surface of the gear-wheel 103. Spring 129 is stronger than spring 107, but sleeve 116 is formed with a cam surface 121 which engages a fixed abutment 123 so that at certain positions of the cam the pressure of spring 129 is relieved, allowing gear 103 to disengage armature 94. Pick-up positioning. Insulating segments 132, 133, mounted between rings 131 threaded on the sleeve 124, pass between contact springs 135, 136 and 137, 138, the two pairs of springs being connected in parallel. Normally, the branch through 135, 136 is closed, but when a 12" diameter record is fed to the turntable, a lever 188, Fig. 14, is actuated which opens the closed branch at 190, 191 and closes the other branch at 191, 192. This transfers control of the magnet circuit from segment 132 to segment 133 whereby the position at which 'the pick-up lands on the record is determined for the 12" record as well as for the 10" record with which the machine is normally set to operate. Detent 194 latches .spring 191 in the position to which it is operated by lever 188, while the positioning and lowering of the pick-up is in progress, but is released by operation of a cam 146 on shaft 45 so that the mechanism may function correctly for the next record. Return of pick-up. As the pick-up moves inwardly across the record, arm 70 and bracket 68 move and segments 132, 133 are rotated anti-clockwise as viewed in Fig. 14, till they move from between the associated contacts which then close. Flange 80 of the lift-rod is then 90. degrees out of the position shown in Fig. 5 with the lift-rod elevated. Magnet 101 is energized, lifting armature 94 which is engaged by gear 103. Flange 80 is thus turned causing lift-rod 63 to move downwardly to lift the pick-up off the record. Sleeve 108 moves downwardly with rod 63 till teeth 99 engage teeth 97 on armature 94 and the swing- ing movement of the pick-up arm begins, first further inwardly and then outward. When the pick-up is clear of the record, abutment 123 and cam 121 co-operate to raise sleeve 116, and gear 103 disengages armature 94 and movement of the pick-up arm stops with the pick-up raised. Record-feeding mechanism. A cam 46 at the top of the shaft 45, Fig. 4; has a nose 47 which acts on a lever 41 for feeding records to the turntable. Lever 41 is connected by a rod 35 to an arm 31 which is secured to a shaft 29 which passes through a non-axial bore in a pin 26, Fig. 3, about which the records are stacked. The records are' supported on the upper surface 33 of a post 7 extending axially of the turntable. Shaft 29 has an eccentric foot 32 of the thickness of a single record and upon rotation of the shaft the lowermost-record on the stack is displaced so as to fall down post 7 on to the turntable. The rod 35 is spring urged to the position shown in Fig. 3 and is enclosed in an arm 14-15 which is hinged at one end so that it can be raised to an inclined position where it may be held by suitable means'(not shown). Records to be stacked are threadod over the post 7 on to the turntable. Arm 14, 15 is lowered with the pointed end 30 of shaft 29 in recess 9 at the top of post 7 so that the post and pin 26 are coaxial. The records are then raised about pin 26 which is displaced to bring end 30 into engagement with recess 8 on post 7 and the records rest on the top of the post. Record steadying and stopping of the machine when the magazine is exhausted. The arm 14, 15 carries two arms 48, 49 which serve to steady records stacked on post 7. The arm 49 is urged downwardly on to the top of the stack by a spring 55 connected to a member 51 on the arm having a pin 52 engaging a slot 54 in a member 53 secured to arm 48 so that the latter is also urged downwardly by spring 55. Arms 48, 49 yield when the stack is exhausted, and pin 52 engages an extension of switch member 57 and closes the switch 57, 58. After the last record has been played, the closure of switch 57, 58 permits the completion of the energization circuit for magnet 178 when a segment 134, Figs. 7 and 14, mounted about sleeve 124, moves between contact springs 139, 140 to open the circuit of magnet 101 and moves spring 140 into contact with spring 141. Armature 174 of magnet 178 is attracted and releases a setting disc 169 on the spindle of operating knob 152. The disc and control knob are then returned by a spring 156 to the stop position, whereat a projection 162 on an insulating disc 159 is inserted between contact springs 163, 164, thereby interrupting the current supply to the machine which stops. Obtaining predetermined intervals between successive playings. The contact springs 139, 140 have a bi-metallic spring 207 connected across them. Element 207 is heated by current passing through a resistance 209 and flexes away from contact 208. Thus, when contacts 139, 140 are opened, contacts 207, 208 will also be open and the current supply will be interrupted till the element 207 has cooled down sufficiently to close its contacts again. The temperature to which element 207 is heated is controlled by adjustment of the value of resistance 209 from a control which thus determines the duration of the intervals between playings. Repeated playing of records and manual operation. Control knob 152 may be set to positions in which a record will be played repeatedly and in which the machine may be operated by hand. For repetitive playing a projection 162 on an insulating disc 161 is moved between contact springs 167, 168 to prevent operation of magnet 178. Movement of knob 152 also causes arm 184, Fig. 7, to engage cam disc 146 and raise the disc and its shaft 45 so that with cam 146 and cam 46 become ineffective. The means for positioning the pick-up thus remains in its set condition and no record is fed to the turntable. For manual operation, projection 162 on insulating disc 160 is moved between contact springs 165, 166 to interrupt the operating circuit for the clutch magnet 101. It is stated in the Specification that the contact springs 135, 136, 137, 138 and 139, 140, 141 and the means for restoring the pick-up arm positioning contacts 190, 191, 192 may be actuated directly by the pick-up arm as it swings.