US2308265A - Speed responsive device - Google Patents

Description

Jan. 12, 1943. H. L. ONE 2,308,265 spam) RESPONSIVE' DEVICE Filed Sept. 27, 1941 5 Sheets-Sheet l INVENTOR [191 /2 e b 0119 BY HIS A'r'ToRNEY Jan. 12, 1943. H. 1.. BONE 2,308,265

SPEED RESPONSIVE DEVICE Filed Sept. 27, 1941 Q 3 Sheets-Sheet 2 INVENTOR Hvbe L. 190m HIS A'IITORNEY Jan. 12, 1943., H. L. BONE 2,308,265

SPEED RESiONSIVE DEVICE Filed Sept. 27, 1941 3 Sheets-Sheet 5 amen Hmbe .flone av Patented Jan. 12, 1943 SPEED RESPONSIVE DEVICE Herbert L. Bone, Forest Hills, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvama Application September 27, 1941, Serial No. 412,665

Claims.

My invention relates to speed responsive devices, and particularly to governors which are adapted for use on trains in connection with automatic train control equipment to limit the speed at which the trains may operate under certain conditions.

One object of my invention is the provision of a small, simple, and light weight governor which is capable of being driven directly from the end of an axle of a car or locomotive, and which has a high degree of sensitivity at predetermined critical speeds both accelerating and decelerating.

Another object of my invention is the provision in a governor of the type described of toggle type v which is proportional to the speed of the vehicle 7 or other device with which the governor is connected, at least one such centrifuge member being provided for each contact speed desired. The centrifuge members are arranged for swinging movement toward and away from the axis of the plate to in and out positions, and are biased to their in positions by means of springs. The parts are so proportioned that when the critical speed at which the centrifuge members are intended to respond is reached, the members will immediately move all the way from their in to their out positions, or vice versa, according as the plate is then accelerating or decelerating. A toggle type contact mechanism is mounted in a fixed position at one side of the path of move ment of each weight element, and is operatively connected with the associated weight element through the medium of a pin carried by the weight element and cooperating with a pair of cams secured to the contact mechanism. The two cams of each pair are provided with opposed cam faces, and the parts are so arranged that when the associated weight element changes its position, the pin will strike one cam face or the other depending upon the position the parts then occupy, and will thereby reverse the contact.

When the contact reverses, the cam which was struck moves out of the path of the pin and subsequently remains out of the path of the pin until the weight element again changes its position, at which time the pin will strike the other cam and will thereby operate the contact to the position corresponding to the new position of the weight element.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I shall describe one form of speed responsive device embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a vertical sectional view showing one form of governor embodying my invention. Fig. 2 is a left-hand view of the governor shown in Fig. 1 with the cover removed to better illustrate the construction of the parts. Fig. 3 is a top view of the governor shown in Fig. 1 with a portion of the cover removed and the remainder shown in section to illustrate the contact mechanism of the governor.

Similar reference characters refer to similar parts in each of the several views.

Referring to the drawings, the governor in the form here shown comprises a housing I provided with a removable cover 2 through which access to the interior of the housing may be had. The housing I is adapted to be secured, in any suitable manner not shown, to the journal box of a railway vehicle adjacent one end of one of the axles of the vehicle, and rotatably mounted in the housing I in ball bearings 3 and 4 disposed in the opposite ends of a bearing opening 5 is a drive shaft 6. This drive shaft is adapted to be driven from the end of the associated axle, and the parts are so arranged that when the housing I is secured to a journal box in the intended manner, the drive shaft will align axially with the axle. The ball bearings 3 and 4 are of the sealed type, and are separated by an annular space for the reception of a suitable lubricant. The drive mechanism for connecting the drive shaft with the associated axle forms no part of my present invention, and is therefore not shown in the drawing. This drive mechanism may, for example, be similar to that shown and described in an application for Letters Patent of the United States, Serial No. 373,132 filed by myself and another on January 4, 1941, for Generator and mounting means therefor.

Secured to the inner end of the drive shaft 6 to rotate therewith is a centrifuge assembly C comprising three centrifuge members 8, 9 and I8 pivotally attached by means of pivot pins H, 52 and [3, respectively, to a bearing plate [4 keyed to the shaft. The pivot pins ll, [2 and i3 are disposed at one end in bushings l5 pressed into the plate id, and at the other end in bushings l6 pressed into bearing straps l1, l8 and I9, respectively. The bearing straps H, l8 and I9 are secured by means of screws 28 to bosses 2| cast on the bearing plate, and shims (not shown) are interposed between the bosses and the bearing caps to provide proper end play for the centrifuge members.

The two centrifuge members 8 and 9 are constrained to operate in unison by means of interconnected arms iI-a and 3a, and together these members constitute a low speed governor. These members are free to swing toward the axis of rotation of the plate 14 to in positions in which stop surfaces 81) and 91) provided on these members engage fixed stop surfaces Ma and Mb provided on the plate [4, and away from the axis of rotation of the plate M to out positions in which other stop surfaces 80 and 9c provided on these members engage other stop surfaces 140 and hid provided on the plate l4, and are con stantly biased toward their in positions by means of compressed coil Springs 22 and 23. The springs 22 and 2-3 are positioned at their outer ends by spring guides 24 and 25 screwed through threaded openings provided in the plate l4, and are held in place at their inner ends by spring guides 9d and 3d provided on the centrifuge members 8 and 9, respectively.

The centrifuge member it) constitutes a high speed overnor, and is free to swing between an in position in which a circular part b which projects into an opening his in the plate [4 engages the side of the opening nearest the axis of the plate l4, and an out position in which the part lfib engages the opening Me at the side farthest from the axis of the plate M. The centrifuge member la is biased to its in position by means of a compressed coil spring 26 similar to the springs 22 and 23. One end of the spring engages a spring guide 2! secured to the plate l4, and the other end surrounds a spring guide 28 secured to the centrifuge member [0.

The characteristics of the springs 22, 23 and 25 and the angles at which they apply force to the associated centrifuge members are such that for all speeds of the plate 14 below certain predetermined critical speeds corresponding to the vehicle speeds at which it is desired to have the high and low speed governors respond, the springs will act to hold the associated centrifuge members in their in positions. However, when the plate i is accelerated to the critical speed at which the low speed governor is intended to respond, the centrifuge members 8 and 9 will then immediately move all the way from their in to their out positions, and, when the plate I4 is accelerated to the critical speed at which the high speed governor is intended to respond, the centrifuge member ID will immediately move all the way from its in to its out position. Likewise, when the plate M is decelerating, and the proper critical speeds are reached, the high and low speed centrifuge members will immediately swing all the way from their out to their in positions. These latter speeds will usually be about 6% lower than the respective speed at which the contact members move to their out positions when the plate 14 is accelerating.

It will be noted that the low speed governor is composed of a pair of interconnected centrifuge members, whereas the high speed governor is composed of a single centrifuge member. The reason for this difference in construction is that the centrifuge members for the low speed governor are required to possess considerable mass in order to develop sufiicient centrifugal force at low speeds, and unless they are balanced in such a manner that they are unaffected by gravity and vibrational forces they will be actuated by these forces and cause improper governor operation (i. e. contact chatter). The necessary balance is obtained by the use of two centrifuge members constructed and arranged in the manner shown. Such a construction is not necessary for the high speed governor since at the higher speeds only a small mass is required to develop the required centrifugal force, and the vibrational and gravitational forces are small compared to the centrifugal force.

The low speed centrifuge member 8 is provided with a laterally projecting pin 8e which operates a low speed contact mechanism LSM, and the high speed centrifuge member 10 is provided with a. laterally projecting pin l0a which operates a high speed contact mechanism HSM. The pins 86 and 10a project from opposite sides of the plate l4, as will be apparent from an inspection of Fig. 1.

As best seen in Figs. 2 and 3, the contact mechanisms LSM and HSM are mounted on contact supports 39 and 3| secured at their ends by means of studs 32 to supporting shelves 33 cast integrally with the opposite side walls of the housing I in confronting spaced relation. These contact mechanisms are similar, and a description of one will suffice for both.

Referring particularly to the low speed contact mechanism LSM, this mechanism comprises a pair of movable contact fingers 34 and 35 which cooperate with fixed contact fingers 34a and 350, respectively, to form contacts 3434a and 3535a. The contact fingers 34 and 34a are clamped to the opposite sides of an insulating block 39 by means of a terminal post 31 which is electrically connected with the finger 34a, but insulated from the finger 34, and a terminal post 38 which is electrically connected with the finger 34, but is insulated from the finger 34a. The contact fingers 35 and 35a are similarly clamped to the opposite sides of the insulating block 33 by means of a terminal post 40 which is electrically connected with the finger 35a, but insulated from the finger 35, and a terminal post 4| which is electrically connected with the finger 35, but insulated from the finger 35a. The insulating block 39 is disposed between insulating blocks 42 and 43, and is secured to the upper side of the contact support 30 by means of studs 44 which pass through clearance holes in all three blocks and are screwed into tapped holes provided in the contact support 33.

The contact fingers 34 and 35 are operatively connected at their free ends to the opposite ends of an insulating strip 36 which is secured intermediate its ends to the upper end of a connecting spring 45. The connecting spring 45 extends downwardly with clearance through a hole 46 provided in the support 30, and is bolted at its lower end to the center of a bowed toggle spring 41. The toggle spring 4'! is secured at its ends to the underside of the contact support 30 by means of clamping blocks 48 and clamping bolts 49, and

cooperates through the medium of cams 50 and with the pin Be provided on the low speed governor. Th cams 50 and 5| are secured to the toggle spring by means of the same bolts which secure the connecting spring 45 to the toggle spring, and are provided with confronting outwardly diverging cam faces.

The parts are so proportioned that the contacts 3 i3 la and 3535a will be closed or open according as the toggle spring 41 occupies its downwardly bowed position in which it is shown in the drawing or is moved to its upwardly bowed position. The parts are further so proportioned that when the toggle spring occupies its downwardly bowed position and the low speed centrifuge members 8 and 9 occupy their in positions, the pin 8c will move between the cam faces 5M and 55a (see Fig. 2) without striking either cam face, but that, if the low speed centrifuge members 8 and 9 move to their out positions when the toggle spring occupies its downwardly bowed position, the pin 8e will then strike the cam surface 56a, and will thereby force the toggle spring past its dead center position, thus causing it to snap to its upper position. The parts are still further so proportioned that when the toggl spring t! occupies its upwardly bowed position if the centrifuge members 8 and 9 are then in their out positions, the pin 86 will move between the cam surfaces Eda and 51a without striking them, but that, if the centrifuge members 8 and 9 move to their in positions under these conditions, the pin 86 will then strike the cam surface em and will cause the toggle spring i'l to to its lower or downwardly bowed position.

It will be apparent, therefore, that with the governor constructed in the manner described, the contacts 3d34a and 35-35a will be closed when the cam plate I4 is at rest or is rotating at any speed at which the low speed centrifuge members 8 and 9 occupy their in positions, but will be open when the bearing plate M is rotated at any speed at which the low speed centrifuge members 8 and 9 occupy their out positions. It will also be apparent that when the contacts C s-Ma and 3535a open or close, they will do so with a snap action.

The operation of the high speed contact mechby the high speed centrifuge member Ill and pin iita is similar to the operation. of the low speed contact mechanism by the low speed centrifuge member 8, and will be apparent from the foregoing description without further detailed description.

It will be noted that the contact operating pins 8e and Ida are so located on their respective centrifuge members that when the centrifuge members are in their mid positions, a line drawn from the axis of the centrifuge assembly C to the center of each cam operating pin will be tangent to the are about which the cam operating pin oscillates in response to movement of the associated centrifuge member between its in and out positions. The force with which the cam operating pins strike the cams causes a reaction on the pins which tends to drive the centrifuge members back to their original positions. This requires that the angle of the cam surfaces and the inertia of the centrifuge members be such as to provide satisfactory operation and still not offer so much resistance that the force with which the pin hits the cam will set up undesirably high forces.

The location of the pins 8e and Ma in the manner shown makes the line of engagement of the forces and the resultant movement on the centrifuge members the same for both directions of rotation of the centrifug assembly, and thus gives satisfactory operation for both directions of operation.

One advantage of contact mechanisms constructed in the manner described is that the associated toggle spring will always assume one extreme position or the other, that is, it will not stick in an intermediate position.

Another advantag is that a definite force, depending upon the number of toggle spring leaves used, their size and the amount they are bowed (i. e. the stroke), is required to move the toggle spring out of either extreme position. The amount that the toggle spring leaves are bowed depends upon how much shorter the distance between the clamping bolts 49 is than the distance between the holes in the toggle spring leaves, and can be adjusted. For example, with four leaf springs .010" thick and A wide adjusted to provide a stroke of /4", a force of approximately 4 pounds is required to move the toggle spring away from either extreme position.

A further advantage of contact mechanisms embodying my invention is that the weight and consequently the inertia of the moving parts, is small, and there are no pivots or toggle cranks to wear or stick. Inasmuch as, especially at high speeds, the contact assembly must move quickly from one position to the other when engaged by the contact operating pins, it is highly desirable that the contact operating structure be as light as possible, not only to give satisfactory operation, but also to prevent the development of destructive forces. The contacts are normally biased to their open positions so that breakage of any of the parts of the contacts will cause the contacts to open. This is very desirable from a safety standpoint.

It should be pointed out that while as shown in the drawing the governor is provided with two sets of normally closed contacts, these contacts can be arranged to be normally open, and, if desired, only one contact, or more than two contacts, can be provided. The contacts are shown as being secured to the left-hand ends of the contact supports 30 and 3|, as viewed in Fig. 2, but these contact supports are so constructed that the contacts may if desired be secured to the right-hand ends of the supports. When the contacts are secured to the left-hand ends of the supports as shown in the drawing, the lead wires may be brought in through an opening provided in the left-hand side wall of the housing I as viewed in Fig. 2, whereas, when the contacts are mounted on the opposite ends of the contact supports, the lead wires may then be brought into an opening 56 provided in the right-hand side wall of the housing I as viewed in Fig. 2.

Although I have herein shown and described only one form of speed responsive device embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A speed responsive device comprising a plate which is adapted to be rotated at different speeds, a stationary contact mechanism mounted ad- .iacent said plate, a centrifuge member mounted on said plate, and means secured to and rotatabl with said centrifuge member for at times operating said contact by impact.

2. A speed responsive device comprising a plate which is adapted to be rotated at different speeds, a centrifuge member secured to said plate for movement toward and away from the axis of rotation of said plate to in and out positions and biased to its in position, the parts being so proportioned that when said plate is accelerated or decelerated to the critical speed at which said centrifuge member starts to move it will immediately move all of the way from its initial position to the other position, a pin secured to said centrifuge member in such a position that when the centrifuge member is midway between its in and out positions a line drawn from the axis of rotation of said plate to the axis of said pin will be tangent to the arc traversed by said pin in moving from its in to its out position, a toggle type contact mechanism mounted adjacent said plate, and cam means provided with opposed cam faces one of which is adapted to be engaged by said pin in response to rotation of said plate to reverse said contact when and only when said contact occupies one position and said centrifuge member occupies its in position and the other of which is adapted to be engaged by said pin in response to rotation of said cam plate to reverse said contact when and only when said contact occupies its other position and said centrifuge member occupies its out position.

3. A speed responsive device comprising a plate which is adapted to be rotated at different speeds, high and low speed centrifuge members pivotally attached to said plate, hi h and low speed contact mechanisms mounted in fixed positions adjacent said plate, pins secured to said centrifuge members, and means included in said contact mechanisms and cooperating with said pins for operatively connecting said high and low speed contact mechanisms with said high and low speed centrifuge members respectively.

4. A speed responsive device comprising a plate which is adapted to be rotated at different speeds, a centrifuge member pivotally mounted on said plate for movement toward and away from the axis of rotation of said plate to in and out positions, a pin secured to said centrifuge memher, a bowed toggle spring secured in a fixed position adjacent said plate, cams secured to said toggle spring and provided with opposed cam surfaces so disposed that said pin will strike the one cam surface in response to rotation of said plate when and only when said spring is bowed in one direction and said centrifuge member occupies its in position and will strike the other cam surface in response to rotation of said plate when and only when said spring is bowed in the other direction and said centrifuge member occupies its out position, the parts being so proportioned that when said pin strikes either cam surface said spring will reverse its position with a snap action, and a contact operatively connected with said toggle spring and operated by movement of said spring between its two bowed positions.

5. A speed responsive device comprising a plate which is adapted to be rotated at different speeds, a centrifuge member pivotally mounted on said plate for movement toward and away from the axis of rotation of said plate to in and out positions, a pin secured to said centrifuge member in such a position that when the centrifuge member is midway between its in and out positions a line drawn from the axis of rotation of said plate to the aXis of said pin will be tangent to the arc traversed by said pin in moving from its in to its out position, a bowed toggle spring secured in a fixed position adjacent said plate, cams secured to said toggle spring and provided with opposed cam surfaces so disposed that said pin will strike the one cam surface in response to rotation of said plate when and only when said spring is bowed in one direction and said centrifuge member occupies its in position and will strike the other cam surface in response to rotation of said plate when and only when said spring is bowed in the other direction and said centrifuge member occupies its out position, the parts being so proportioned that when said pin trikes either cam surface said spring will reverse its position with a snap action, and a con tact operatively connected with said toggle spring and operated by movement of said spring between its two bowed positions.

HERBERT L. BONE.

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