US2965377A

US2965377A - Automatic phonograph tripping mechanism

Info

Publication number: US2965377A
Application number: US673735A
Authority: US
Inventors: Boer Petrus A De
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-07-23
Filing date: 1957-07-23
Publication date: 1960-12-20
Anticipated expiration: 1977-12-20

Description

Dec. 20, 1960 P. A. DE BOER AUTOMATIC PHONOGRAPH TRIPPING MECHANISM Filed July 23, 1957 v INVENTOR PETR S ANTONIUS DE 8051 ATTORNEY AUTOMATIC PHONOGRAPH TRIPPING MECHANISM Petrus A. De Boer, 60 Godelindeweg, Naarden, Netherlands Filed July 23, 1957, Ser. No. 673,735

2 Claims. (Cl. 274-15) The invention relates to a phonograph with cam mechanism for the automatic control of the pick-up arm, said mechanism being set rotating stepwise between the playing of two records by a pawl rod, which receives a reciprocating movement from the spindle of the turn-table and acts on a ratchet wheel connected with the cam mechanism.

A phonograph of this type is known from the U.S. Patent No. 2,620,194.

According to the invention this device is constructed in such a way: that after a number of rotational steps of the ratchet wheel the pawl rod is engaged and seized by the ratchet wheel; that at the end of the subsequent rotational step the ratchet wheel receives a pre-rotation, which terminates the action of the spindle of the turn-table on the pawl rod; and that upon the needle entering the terminal groove of the record being played the engagement of the pawl rod by the ratchet wheel is eliminated.

By this means the advantage is gained that the driving motor of the phonograph is not loaded, during the playing of the record, by the reciprocating movement of the pawl rod and, consequently, need not perform work to bring about this movement. Objectionable interfering noises, which may be caused by the moving parts during the playing of the record, are thus avoided; the motor may be made smaller and wear is minimized.

The invention is to be elucidated more in detail with reference to the drawing, which shows a diagrammatic plan view of an embodiment.

Fig. 1 shows only the essential parts of the device according to the invention.

Fig. 2 shows the same parts, and in addition an embodiment of a device for eliminating the engagement of the pawl rod by the ratchet wheel upon the needle entering the terminal groove of the record played.

The reference number 1 designates the spindle of the turntable. Fitted eccentrically on this spindle is a disc 2. The disc 2 co-operates with a lever 3, which is adapted to pivot about a stationary axis 4. Connected with the free end of the lever 3 and adapted to pivot about it is a pawl rod 5. The righthand end of the pawl rod 5 has been shaped like a hook 6 and co-operates with a ratchet wheel 7 of a cam mechanism (not shown) for the automatic control of the pick-up arm during the changing of a record; said cam mechanism has not been shown in the drawing because it does not form part of the invention.

The toothing of the ratchet wheel 7 has been constructed locally at 8 in such a way that the pawl rod 5 can be engaged and seized by the ratchet wheel 7.

The pawl rod 5 is acted upon by a tension spring 9, which tends to hold the lever 3 against the disc 2 and the pawl rod 5 against the ratchet wheel 7.

The reference number 10 designates a member which, when moved in the direction of the pawl rod 5, eliminates the engagement of the pawl rod 5 with the ratchet wheel 7.

Fitted on the upper surface of the ratchet wheel 7 is a non-circular disc with a cam 13. Against the rim of ate 2,965,377 Patented Dec. 1960 the non-circular disc 15 presses, under the influence of a spring 16, the end of an arm 14, which is adapted to pivot about a stationary pivot 17.

The device according to the invention is shown in the position in which it is when a record is being played on the phonograph. In this position the ratchet wheel 7 is stationary The free end of the arm 1-4 rests against the flank of the cam 13. Owing to this the ratchet wheel 7 cannot rotate in clockwise direction. The hook 6 rests in the engaging recess 8. In consequence the position of the pawl rod 5 is such that the disc 2 during its continual rotation cannot come into contact with the lever 3. The pawl rod 5 therefore is stationary.

When at the end of the record played the needle of the pick-up arm enters the terminal groove of said record, then in a manner to be explained more in detail the member 10 is briefly pressed against the pawl rod 5. In consequence the hook 6 is lifted from the engaging recess 8. The pawl rod 5 is then pulled to the right by the spring 9, and the lever 3comes to rest against the disc 2. During the next revolution of the disc 2 the pawl rod moves to the right until the hook 6 engages behind the next tooth 11 of the ratchet wheel 7. During the subsequent regular reciprocating movement of the pawl rod 5 under the influence of the disc 2 the ratchet wheel 7 is rotated stepwise in the direction of the arrow 12. Through this stepwise rotation the automatic control of the pick-up arm during the changing of the record is brought about.

After some time the recess 8 arrives to the right of the place where in Fig. l the reference number 11 has been placed. During the subsequent movement to the right of the pawl rod 5 the hook 6 is engaged and seized by the recess 8. If the pawl rod 5 then moves to the left again, the position reached is approximately the one i1- lustrated in 1. This position is not reached to the full, since the movement to the left ofthe pawl rod 5, conditionedby the disc2, is not sufficient for this purpose.

At the end of thismovement the cam 13 is rotating gets clear of the arm 14. The end of thearm 14 consequently comes to rest on the flank of the cam, as a result of which, under the influence of the spring 16, a small further rotation in the direction of the arrow 12 is imparted to the ratchet wheel 7. This rotation is such that the position of Fig. 1 is now reached again.

The small further rotation results in that the pawl rod 5 is displaced slightly to the left by the righthand flank of the recess 8. This displacement puts the lever 3 out of reach of the disc 2. In this way it is ensured that the pawl rod 5 performs no reciprocating movement during the playing of a record. The motor of the phonograph accordingly need not perform any work to bring about this movement, and the wear of the parts involved in this movement is minimized.

Fig. 2 will now be discussed. From this it appears how it can be ensured that upon the needle entering the terminal groove of the record being played, the member 10 is briefly pressed against the pawl rod 5. In so far as the same parts of Fig. 1 appear in Fig. 2, they have been given the same reference numbers.

The member 10 forms part of a lever 18, adapted to pivot about a stationary axis 19. The lefthand end 20 of the lever 18 is bevelled and lies in the path of travel of a pin 21, which follows the rotation of the spindle 1 of the turn-table. When the pin 21 comes into contact with the end 24), the lever 18 is slightly rotated in counterclockwise direction about the spindle 19.

The reference number 22 designates the pick-up arm; this is shown in dotted lines because it lies above the level of the other parts. The reference number 23 designates the spindle of the pick-up arm. Secured to the spindle 23 is an arm 24; the latter accordingly follows the movements of the pick-up arm.

A plate 26 is adapted to rotate with friction about a spindle 25 supported by the arm 24. This plate 26 rests against the righthand part of the lever 18.

When during the playing of a record the pick-up arm 22 gradually comes closer to the spindle 1 of the turntable, the arm 24 and, owing to the friction between said arm and the plate 26, also the plate 26 is carried along. With every revolution of the turn-table the left hand end 20 of the lever 18 will be moved a short distance in the direction of the spindle 1. Upon the pin 21 passing along the bevelled portion of the end 20, however, said end is each time pushed back again the same distance. The average position of the lever 18 will thus remain the same.

However, when the needle enters the terminal groove of the record being played, the pick-up arm will suddenly receive a greater displacement. This displacement is also transmitted to the lever 18 by the plate 26, and ensures that the lefthand end 20 of the latter is engaged by the pin 21 and that the lever 18 reaches the position shown in dotted lines, and with its righthand end 10 eliminates the engagement of the pawl rod 5 with the ratchet wheel 7. Shortly afterwards the pawl rod 5, under the combined influences of the spring 9 and the disc 2, moves to the right. During this movement the member 10 is pressed back by an appropriately shaped projection 27 on the pawl rod 5, so that the hook 6 can engage the next tooth of the ratchet wheel 7.

When the pick-up arm 22 sways outwards after a record has been played, the plate 26 comes into contact with a stationary pin 28, as a result of which, while overcoming the friction between said plate and the arm 24, it is put in the right position for the playing of the next record.

The device described for operating the member 10, in which a servo mechanism is employed, only serves as an example. The member 10 can also be caused to be controlled direct by the pick-up arm, or the pawl rod 5 can be disengaged from the ratchet wheel 7 by means of the lever 24, in a modified form thereof.

The invention naturally is not confined to the feature that the pawl rod 5 exercises a pulling action on the .vided.

What I claim is:

1. In a record player, a shaft adapted to control a pick-up arm control cam, a ratchet wheel on said shaft, said ratchet wheel having a recess therein, a turntable spindle having a disc thereon, a pawl rod engageable with said ratchet wheel and operatively connected with the said disc to cause rotation of said ratchet wheel upon rotation of said spindle, means to operatively disconnect said pawl rod from said disc consequent on said pawl rod engaging with the recess of said ratchet wheel comprising a noncircular disc on said shaft having a steep shoulder and a spring-urged lever engageable with said shoulder of said noncircular disc, said shoulder, when engaged by said spring-urged lever, adapted to yield to the force of said spring-urged lever to cause rotation of said noncircular disc, said shaft, and said ratchet wheel to disconnect said pawl rod from said spindle, and means operable upon entry of the needle in the terminal groove of a record on the turntable to disengage said pawl rod from said recess.

2. A record player according to claim 1 wherein said means to disengage said pawl rod from said recess comprises a pivoted lever one end of which is engageable with the pawl rod; an arm which follows the movements of the pick-up arm, a plate frictionally mounted on said arm whereby upon the needle of said pick-up arm entering into the terminal groove of the record, said plate moves said end of the pivoted lever against said pawl rod, thereby disengaging said pawl rod from said recess.

References Cited in the file of this patent UNITED STATES PATENTS 2,436,529 Pressley Feb. 24, 1948 2,747,879 Bacher May 29, 1956 2,803,465 Dobrogowski et al. Aug. 20, 1957