US2829754A

US2829754A - Centrifugal tab governor

Info

Publication number: US2829754A
Application number: US478224A
Authority: US
Inventors: John H Norcross
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1954-12-29
Filing date: 1954-12-29
Publication date: 1958-04-08
Anticipated expiration: 1975-04-08

Description

April 8, 1958 J. H. NORCROSS CENTRIFUGAL TAB GOVERNOR Filed Dec. 29, 1954 FIG. I

JNVENTOR.

JOHN H. NORCROSS (Muddy ATTORNEY III/ll eration.

2,829,754 CENTRIFUGAL TAB GOVERNOR John H. No'rcross, Poughkeepsie, N. Y., assign-or to International Business Machines Corporation, New York,

N. Y., a corporation of New York 7 Application December 29, 1954, Serial No. 478,224

a 2 Claims. (Cl. 197-64) This invention relates to typewriters and more particularly to an improved governor for a typewriter carriage.

. It is well known in the art that it is necessary to provide some sort of a speed governor on a carriage in order to reduce shock after a tabulation run. The governor is connected to the carriage so as to be operable only when the carriage is moving in its normal escapement direction, and to be inoperable during a carriage return operation. One specific example of a tabulation governor is shown. in U. .5. Patent 2,129,650 assigned to the same which type has been used in prior arttypewriters. However, the conventional embodiment of centrifugal force governors have been found noisy and expensive, there fore, it is a first object of this invention to provide an improved inexpensive centrifugal force governor.

It is a further object of this invention to provide an improved centrifugal force governor which is quiet in op- It is a still further object of this invention to provide an improved. centrifugal force governor wherein the coefficient of friction between the operating surfaces will remain constant through prolonged use.

It is a still further object of this invention to provide an improved integral housing and mounting means for a centrifugal force governor.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose by way of example, the principle of the invention and the best mode,

which has been contemplated of applying that principle.

In the drawings:

Fig. 1 is a rear elevation of portions of a typewriter carriage and carriage control mechanism.

Fig. 2 is a side elevation taken through the plane 22 of Fig. 1 in the direction of the arrows; while Fig. 3 is a front view of the centrifugal force governor and mounting means shown in Fig. l.

Briefly, this invention relates to an improved centrifugal force governor wherein the housing and mounting means are an integral molded piece and wherein the flyweights have a nylon insert therein for contact with the inner-peripheral surface of the molded phenolic housing, whereby when the flyweights are forced outwardly through the inter-engagement of a motor gear and the pinion driving the flyweight shaft through a spring clutch, the nylon insert will engage the inner-peripheral phenolic surface United States Patent of thehousing to effect a braking force in response to the carriage speed.

With reference to the drawings, a carriage 2- is indicated as being moved in letter spacing (or normal escapement) direction by tape 4 which interconnects the garriage 2 with a well known spring motor 6. The lat- 2,829,754 Patented Apr. 8, 1958 "ice ter is mounted on the frame of the typewriter by some bolt or other mounting means 8.

It is well known that the carriage normally moves in the directionof the arrow under the influence of the spring motor 6 as controlled by an escapement pawl mechanism which is: not shown. As the pawl is stepped is pivotally supported for movement into and out of the plane of the paper abouta pivoting mechanism 18 so that the bent over tab stop.20 is moved outwardly to engage a tab stop in a well known manner as the right hand end 16 is pivoted into the plane of the paper. In the process of setting the tab lever for a tab operation, a pawl control lever 22 is rocked by the tab check lever outof the plane ofth'e paper to lift the escapement pawls out of the escapement rack ltlwhereupon the carriage is free to travel in the direction of the arrow under the influence of tape 4 and spring motor 6.

In order to control the speed of the carriage during a tabulation run, a tabulation governor 24 is providedto be operable in response to the speed of the carriage.- The governor 24 comprises a combined housing and bracket member 26, a flyweight member 28 and a shaft 30 connected through a spring clutch 32 to a pinion 34. The pinion 34, in turn, is meshed with a motor gear 36 coaxially mounted with respect to the spring motor 6v to .be

rotatable therewith.

The combined housing and bracket 26 is molded from one of the phenolics, such as Bakelite to provide anin;

tegral cylinder 37, bushing 38 which supports a pair of

bearings

40, 42 in which the shaft 30 is mounted for rotation relative tothe cylinder 37, and a mounting bracket 441' The bracket 44 is provided with a mounting aperture 46 plus an integral mounting brace formed by the

sides

48, 50 which ride in a complementary mounting portion of the typewriter frame (not shown). Through this structure, the governor can be mounted on the typewriter frame with its pinion 34 in engagement with the motor gear 36 through the operation of a single screw passing through the aperture 46.

A disc 54 is pinned or otherwise secured to the shaft 30, and in turn, provided with a pair of

mounting apertures

56, 58 for holding a pair of shafts 60, 62 parallel to shaft 30 and for rotation about its axis.

Conventional flyweights

64, 66, respectively, are mounted on the shafts 60, 62, respectively, and held in place by clips 68, thereby providing for pivotal movements of the flyweights about their supporting shafts 60, 62. Each flyweight has a

notch

72, 74 formed therein respectively, for carrying

nylon inserts

76, 78 which extend peripherally beyond the outer limits of the flyweights thereby being adapted for engagement with the inner-peripheral surface of the cylinder 37. The flyweights are held normally together in a conventional manner by a spring 80 (which may be positioned selectively in various of the holes 81 to vary the operating range of the governor), and in order to reduce the noise of the flyweights returning to their normal position, each one has an

insert

82, 84 respectively, of nylon or other resilient material, which engages the

hubs

86, 88 respectively, of the adjacent flyweights.

The advantage of the use of the

nylon inserts

76, 78 is that the material will not tend to rub off and coat the inner-peripheral surface of the cylinder 37 and, therefore, the co-efiicient of friction existing between the nylon it);

without departing from the spirit of the invention.

serts and the inner-peripheral surface of the cylinder 37 will remain constant thereby alleviating the necessity of adjusting the operation of the governor even after considerable use. r

The outer end of shaft 30 carries a mounting bushing 90 secured by a set screw 92 to the shaft]; The spring clutch 32 is mounted to peripherally grip the hub'94 of the bushing 90 and the hub 96 of the gear 34 in such a manner that the spring is tightenedwhen pinion 34 is rotated counterclockwise as viewed in Fig. l. The tightening of the spring 32 grips the hub 94 of the bushing 90 to rotate shaft 30 counterclockwise (Fig. 1) which would be clockwise as viewed in Fig. 3.. 'When the carriage is moved in a direction opposite'to the arrow of Fig. 1, however, spring 32 is unwound to disengage the hub 94 from the pinion 34 so that the flyweights will not move outto engage the wall of cylinder 37.

The clockwise rotation of the shaft 30 as viewed in Fig. 3, will cause the

flyweights

64, 66 to pivot about their respective supporting shafts 60, 62 so that the nylon inserts 76, 78 engage the inner peripheral surface of the cylinder 37 with a force that is proportional to the speed of rotation of the shaft 30. Accordingly, a braking force is applied to the carriage, which braking force is responsive to the speed of the carriage over its whole range of speed travel. I t

It has been found that the nylon Bakelite combination maintains'the same co-efficient of friction through prolonged periods of operation, thereby establishing a speed control on the carriage which is sensitive to the carriage' speed and which will operate without required adjustment during the prolonged periods.

While there have been shown and described and pointed out the fundamental novel features of the invention, as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, It isthe intention, therefore, to be limited only as indicated by the scope of the following claims;

What is claimed is: 1. In a typewriter having a'carriage freely movable under the control of the spring motor during a tabulation run, a speed responsive governor operable to regulate the speed of the carriage during its flight comprising an integral phenolic mounting bracket and housing defining a cylinder, a shaft mounted in said housing coaxially of said cylinder, at one way driving means interconnecting said shaft and said carriage to provide for rotation of said shaft in response to carriage flight, a plate having a pair of flyweights pivotally mounted thereon, and means interconnecting said plate coaxially of said shaft to be rotatable therewith whereby said flyweights will pivot outwardly in response to centrifugal force, said flyweights having nylon inserts therein at their point of engagement with the inner periphery of said cylinder wall whereby a speed responsive governor having a substantially uniform coeliicient of friction is provided for limiting the speed of said carriage during a tabulation run.

2. In a typewriter having a carriage freely movable under the control of the-spring motor during a tabulationrun, a speed responsive governor operable to regulate the speed of the carriage during flight comprising an integral Bakelite mounting bracket and governor housing defining a cylinder, a shaft mounted in said housing coaxially of said cylinder, spring clutch means interconnecting said shaft with said spring motor whereby said shaft is rotated at a rate proportional to carriage speed during a tabulation run, a plate having a pair of spaced apart fiyweights pivotally mounted thereon, and means mounting said plate coaxially of said shaft for rotation therewith to cause said flyweights to pivot outwardly as a result of centrifugal force, said flyweights having nylon inserts therein as their point of contact with the inner peripheral wall of said cylinder, whereby said nylon inserts act as brake shoes to provide a speed responsive governor having substantially a uniform coefficient of friction, irrespective of length of use.

References Cited in the file of this patent i UNITED STATES PATENTS 880,158 McFarland et al. Feb. 25, 1908 946,797 Ford Jan. 18, 191 0 1,005,781 Raber Oct. 10, 1911' Richter May 19, 1925