US2244760A - Speed responsive device - Google Patents

Description

June 10, 1941'.

H. L. BONE SPEED RESPONSIVE DEVICE Filed June 30, 1958 5 Sheets-Shea; 1

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Patented June 10, 1941 SPEED RESPONSIVE DEVICE Herbert L. Bone, Forest Hills, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application June 30, 1938, Serial No. 216,718

16 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 to provide a governor of the type described which can be mounted on and driven from the end of an axle of a train, and which includes means whereby the governor contacts can be readily made to operate at the desired car speeds regardless of the particular diameter of the wheels which support the axle from which the governor is driven.

A further object of my invention is to provide in a governor of the type described means for changing the setting of the governor contacts to compensate for wheel wear to enable the speeds at which the governor contacts operate to be readily maintained at the same values throughout the life of the wheel.

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

Governors embodying my invention are an improvement on the governor disclosed and claimed in a copending application for Letters Patent of the United States, Serial No. 205,276, filed by myself and John W. Livingston on April 30, 1938, now Patent No. 2,211,554, August 13, 1940, for Speed responsive devices, and also on the governor disclosed and claimed in Letters Patent of the United States No. 1,878,305 granted to Per Utne on September 20, 1932, for Speed responsive devices.

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

In the accompanying drawings, Fig. 1 is a front elevational view of a governor embodying my invention with one of the covers removed to illustrate the contact structure of the governor. Fig. 2 is a vertical longitudinal sectional view of the governor shown in Fig. 1. Fig. 3 is a sectional view taken substantially on the line III-III of Fig. 1. Fig. 4 is a sectional view taken substantially on the line IV-IV of Fig. 2. Figs. 5 to 8, inclusive, are detail views showing various construction features of the governor illustrated in the preceding views. Fig. 9 is a graph showing the operating characteristics of the governor illustrated in the preceding views.

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

Referring first to Figs. 1 to 4, inclusive, the governor in the form here shown comprises a suitable housing I which encloses all of the operating parts of the governor, and which 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 2 of the vehicle. In keeping with modern tendencies to reduce weight to a minimum, it is desirable that the housing should be as light as possible, and to this end the housing is preferably in the form of a single unit heat treated alloy casting provided with such openings as are necessary or desirable to permit ready assembly of the parts and subsequent access to them for inspection, maintenance or repair. The housing openings are all closed by suitable cover plates or otherwise, as will appear from an inspection of the drawings, to prevent the introduction of dirt, moisture or other foreign substances into the housing, and to retain within the housing the necessary lubricants.

The interior of the housing I is divided by means of suitable partition walls into two compartments 3 and 4, and rotatably mounted in the lower end of the compartment 3 in axial alignment with the axle 2, by means of roller bearings 5 is a helical gear 6. This gear is driven by the axle 2 through the medium of a flexible coupling 29, and meshes with a helical gear I secured to a member B comprising part of a centrifuge device. The flexible coupling 29 is similar in all respects to that shown and described in the aforementioned Bone and Livingston application, Serial No. 205,276, and inasmuch as this coupling forms no part of my present invention it is believed to be unnecessary to describe it in detail herein.

The member B is rotatably mounted in the compartment 3 in a vertical position at one side of the helical gear 6 by means of suitable antifriction bearings, here shown as a roller bearing 8 and a ball bearing 9, and comprises two spaced longitudinally aligned tubular spring housings III and I I connected together by two integral transversely spaced parallel side plates I2. The confronting ends of the spring housings are provided with inwardly extending annular flanges Illa and Ila which form openings lb and Nb, respectively, and extending with some clearance through the opening Iilb into the housing III is a rod I3, the lower end of which is provided with what may be termed a piston I I, and the upper end of which is secured to a link head I5. A rod I6 similarly extends with some clearance through the opening IIb into the housing II and is provided at its upper end with a cup-shaped piston I1, and is secured at its lower end to a link head iii. A coil spring is surrounds the rod l3 between the piston l4 and the flange Illa, and biases this rod to a lower position in which the link head engages the flange Mia, and a compressed coil spring 29 similarly surrounds the rod IE between the piston H and the flange Ha. For reasons which will appear hereinafter, spring 28 is lighter in weight and has a flatter rate than spring 59. Furthermore, spring 2i: is of such length that it has a slight initial compression with the centrifuge at rest, while spring Ii is made somewhat shorter than spring 24), so that this spring will not come into action until the centrifuge has reached a predetermined speed, for example 2E3 axle revolutions per minute. The side plates l2 of the member B support a transversely extending shaft 2| which is located at equal distances from the two spring housings l3 and H, and which passes through the axis of the member B at right angles thereto, and mounted on this shaft are two crossed centrifuge arms 22 and 23, each arm, as here shown, being made up of two parallel members. One end of each centrifuge arm 22 and 23 is pivotally connected by means of links 24 and 25 with the link head i5, and the other end of each centrifuge arm is pivotally connected by means of links 2'3 and 23 with the link head [8.

It will be seen, therefore, that when the member B is rotated, the resulting centrifugal force I will tend to move the centrifuge arms into a common plane which is perpendicular to the vertical axis of the member B, and that, until the centrifuge attains the axle speed at which the spring i9 comes into play, the centrifugal force will be opposed by the force exerted by the spring 20, but that, above this axle speed the centrifugal force will be opposed by the force exerted by both springs. It will also be seen that as the speed of rotation of the member B increases, the pistons l4 and I! will move toward each other, and as the speed of rotation of the member B decreases, these two pistons will move away from each other.

For the purpose of providing adequate lubrication to the centrifuge and associated driving gearing, the lower end of the compartment 3 is filled with oil, and an oil pump C is provided whereby this oil is pumped upwardly through a pipe and is caused to flow downwardly over the member 13 and associated parts. This pump may be similar in construction to the oil pump described in the aforementioned Bone and Livingston application, Serial No. 205,276, and is driven by the member B in the manner described in the said Bone and Livingston application.

The piston I! of the centrifuge device is provided at its upper end with a reduced portion which, together with a washer 3| which is clamped against this reduced portion by means of a castellated nut 32, forms an annular groove 53, and extending into this groove at diametrically opposite points are two rollers 34 mounted on a crack arm 35 secured to one end of a shaft 36. The shaft 36 is journaled at the end nearest the crank arm in a bushed bearing 3'! for oscillation about an axis perpendicular to the longitudinal axis of the member B and extends into the compartment 4 through a small compartment 38 formed between the two compartments 3 and 4. It will be apparent, therefore, that the shaft 35 will be rotated in one direction in response to an increase in the speed of rotation of the member B, and in the opposite direction in response to a decrease in the speed of rotation of the member B,

The bearing 31 is mounted in a wall of the casing 1 which is common to the two compartments 3 and 38, and in order to prevent any oil which may work past this bearing from getting into the compartment 4, a concave oil deflecting plate 39 is pressed onto the cam shaft adjacent the righthand side of the bearing. This plate is disposed within a clearance hole 40 formed in the wall of the casing l which is common to the two compartments 38 and 4, and cooperates at its righthand side with an oil retaining plate 4| secured to the wall of the compartment 38. Any oil which leaks into the compartment 38 is permitted to drain back into the compartment 3 by a passageway 42 formed in the bottom of the compartment.

Endwise movement of the shaft 36 in one direction is prevented by a thrust washer 43 interposed between the crank arm 35 and the bearing 31, while endwise motion of the shaft in the opposite direction is prevented by the flange on bushing 31 and plate 39.

A cam sleeve 45 is mounted on the portion of the cam shaft 36 which is disposed within the compartment 4 in such manner that this sleeve is free to move longitudinally relative to the shaft through a limited distance. This sleeve, however, is constrained to rotate with the shaft by means of a key 41 which cooperates with a keyway 48. The right-hand end of the sleeve cooperates with means which I shall describe presently for moving the sleeve longitudinally relative to the shaft to different positions, and the sleeve has mounted thereon a plurality of contact controlling cam segments, here shown as four in number and designated by the reference characters 5%., b, 50c and 50d, respectively. These cam segments operate an associated group of contacts through the medium of rollers 5la, 51b, 5lc and 5ld (Fig. 5), respectively, secured to rocker arms 52a, 52b, 52c and 52d, as will be explained more fully hereinafter, and in order to permit these groups of contacts to be selectively operated at the required car speeds, it is desirable to be able to readily adjust the angular position which each cam segment occupies with respect to the cam sleeve. To this end, the hub of each cam segment is split, and has mounted therein two screws 53 and 54. The one screw 53 serves as a means to rotate the segment to different positions, and meshes with worm teeth cut in a groove formed in the cam sleeve, while the other screw 54 serves as a means to draw the split portion of the hub together and thus clamp the segment in its adjusted position. It will be seen, therefore, that if it is desired to change the angular position of any cam segment with respect to the shaft, this may be quickly and conveniently done by first loosening the clamping screw 54, then rotating the adjusting screw 53 in one direction or the other until the segment is moved to the desired angular position, and then again tightening the clamping screw.

For reasons which will appear hereinafter, the widths of the cam segments and the lengths of the associated rollers are so proportioned that each roller will engage the associated cam segment in any longitudinal position to which the cam sleeve is free to move if the cam shaft is rotated to the proper angular position, and secured to the cam segments adjacent their lower edges are cam plates 55a, 55b, 55c and 55d, one edge of each of which is beveled at an angle to the cam shaft, as shown in Fig. 2, and forms a continuation of the cam face of the cam segment in such manner that by moving the cam sleeve longitudinally to different positions, the angular positions of the cam shaft at which the rollers will engage the cam faces of the associated cam segments may be simultaneously varied in a predetermined manner. The rocker arms 52a, 52b, 52c and 52d are pivoted at their upper ends on pins 51a, 51b, 51c and 51d mounted in bifurcated supports 56a, 56b, 56c and 56d secured by means of screws 51c in the manner shown in connection with the rocker 520 in Fig. 3, to a bracket 58, and the bracket 58, in turn, is secured to the housing I within the compartment 4 by means of studs 59, which studs also serve to secure an insulating panel 60 to the bracket. Interposed between each support and the bracket are one or more shims 6|, the functions of which will be made clear presently. The lower end of each rocker arm is pivotally attached to a push rod assembly designated by the reference character 62 with a distinguishing subscript, and the free ends of which are slidably supported in openings 63 formed in the panel 68. Each push rod assembly is of moulded insulating material, and comprises a pair of push rods which are provided intermediate their ends with confronting bosses, and which are clamped together at the bosses by a bolt 64, to form an H-shaped structure having a central arm or cross bar 65. The cross bar on the side facing the rocker cooperates with a depending stop arm 66 formed on the bracket 58, and interposed between each rocker and the associated stop arm is a coil spring 99 which constantly biases the rocker to the position in which the cross bar of the associated push rod assembly engages the stop arm. The other side of each cross bar cooperates with a flexible contact finger 68 disposed on the rear side of the panel, while the outer ends of the push rods cooperate with flexible contact fingers 69 and 16 disposed on the forward side of the panel. Each finger 68 is secured to the panel at its upper end by means of a terminal post II, and cooperates at its lower end with a relatively stiff contact finger 12 to form a contact 68'|2. The finger 18 in turn is clamped at its lower end between two metal blocks 19 and 80 which are secured to the panel 68 by means of a terminal post 15, and is pierced adjacent its upper end to receive with some clearance an adjusting screw 8|. The screw 8| is mounted in a threaded opening provided in an upstanding projection formed on the outer block 80, and carries a pair of lock washers 82 and a lock nut 83 disposed on the side of the projection opposite to the finger 12. The nut 83 is prevented from rotating by a slotted leaf spring 84 which straddles the nut, and which is riveted to the projection. It will be apparent that by pushing the upper end of the leaf spring inwardly to the point in which the slot is clear of the nut, the nut can be turned, and the nut is so adjusted that it will produce sufiicient friction on the threads of the screw to cause the screw to remain at any position to which it is adjusted. It will be obvious, of course, that by adjusting the screw the position of the finger 12 can be varied, thus providing a convenient means for adjusting the position of the rocker at which the contact 68-12 opens, as will be pointed out somewhat more fully hereinafter.

The flexible fingers 69 and Ill are secured at their upper ends to the panel 60 by means of terminal posts I1 and I6, and clamped against the forward face of each finger is a leaf spring 85, the length of which is such that its lower end is disposed approximately opposite the point at which the associated push rod engages it. The lower end of the flexible fingers 69 and 10 cooperate with fixed contact members 89 and 90 to form contacts 69-89 and l090, respectively, these fixed contact members being secured to the panel by means of suitable terminal posts 18 and 14.

The fiexible contact fingers are biased by their own resiliency to the positions in which the associated contacts are all closed, and the parts are so proportioned that when the roller carried by any rocker is out of engagement with the associated cam segment, the associated contacts will all be closed, but that when the roller carried by any rocker is engaging the face of the cam segment, the contacts will all be open. The parts will usually be further so proportioned that the four groups of contacts will be operated at different vehicle speeds as the speed of the vehicle changes.

In adjusting the contacts of any group, the cam shaft 96 is first rotated to the position in which the roller on the rocker associated with such group of contacts is clear of the associated cam segment, and the associated depending stop arm 66 is then bent to such a position that when the cross bar of the associated push rod assembly is engaging the stop, the ends of the push rods will clear the fingers 69 and 10 to permit these fingers to engage the associated fixed contact members 89 and 98. The shaft 36 is next rotated to the position in which the roller on the rocker is riding on the face of the cam segment, and shims 6| are inserted between the rocker supports and the frame having the necessary thickness to cause the push rods to move the fingers away from the associated fixed contact members a sufficient distance to provide the desired front contact opening. The screw 8| is next so adjusted that as the roller 5| rides up onto the cam segment, the contact 68-42 will open at a speed of approximately 1 mile per hour below the speed at which the other contacts open. It should be noted that during this latter adjustment if the finger 12 is moved toward the right as viewed in Fig. 3, the finger 68 will tend to follow it, and since the distance between the tips of the push rods and the cross bar of the push rod assembly is fixed, the distance moved by the push rod assembly between the point at which the contact 68|2 and the contacts 6989 and l09ll open is varied.

In order to be able to readily obtain the last mentioned adjustment, it is necessary that the number of turns of the screw 8| necessary to cause a difference of 1 mile per hour between the opening of the contact 68'|2 and the opening of the contacts 69-89 and Ill-90 of any group should be at least two or three, and the manner in which the finger 66 and the fingers 69 and I0 flex when they are being moved in the direction to open the contacts has a marked effect on this adjustment. The proper flexing of the fingers 69 and 10 to obtain the desired adjustment can best be obtained by providing the previously described leaf springs to control the flexing of these fingers. With this arrangement, the fingers 69 and I0 begin to exert pressure against the push rods of the push rod assembly before the associated contact 66-12 opens, and by the time this contact is almost open, most of the load due to the springs 69 and 10 has been transferred to the push rods so that only a slight increase in governor speed is necessary to move the cam segment sufliciently to open the contacts 69-89 and 'I090. The fingers 69 and I are quite flexible, and as a result, the motion of the push rod required to move the fingers B9 and In from the positions in which the associated contacts are fully closed to the positions in which these contacts just open is rather long, and the point in this travel at which motion of the push rod causes the contact 68-42 to open can be varied quite accurately by adjustment of the screw 8|.

When a governor is driven directly from a car axle in the manner described, it will be apparent that the centrifuge speed for a given car speed will be directly proportional to the diameter of the wheels which support the axle, and it follows, therefore, that with the governor constructed in the manner thus far described, if the governor contacts are set to operate at the desired car speeds for wheels having a particular diameter, and it is subsequently desired to use the governor on a car having wheels of a different diameter, or if the wheels decrease their diameters due to wear, it will be necessary to individually reset the cam segments to cause the contacts to again operate at the same car speeds. This individual adjustment of the cam segment requires a. com siderable amount of time and equipment, and my present invention resides primarily in the provision of means whereby when the governor contacts have been adjusted to operate at the desired car speeds for wheels of a particular diameter falling within the range of diameters usually encountered in practice, the contact setting of all four groups of contacts can be simultaneously varied with a minimum amount of effort to cause the contacts to operate at the same car speeds for any other wheel diameter falling within the usual range of diameters.

As here shown, these means comprise the previously described beveled. cam plates 55a, 55b, 55c and 55d which are attached to the cam segments 50a, 56b, 50c and 50d, and the means which I shall now describe for sliding the cam sleeve 45 longitudinally along the cam shaft 36 to predetermined positions to enable the angular positions of the cam shaft at which the rollers 5Ia, 5Ib, 5Ic and 5Id engage the cam plates to be simultaneously varied. The means for sliding the cam sleeves longitudinally in the form. here shown comprises a suitable casing I00 which is bolted to the governor housing I adjacent the right-hand end of the cam sleeve 45, and which 4 is provided with a hole i6! disposed in axial alignment with the sleeve. The hole IOI, in turn, is provided with helical threads, and screwed into this hole is a hollow sleeve shifting nut I02, the inner end of which receives the right-hand end of the cam sleeve 45, as viewed in Fig. 2, with some clearance, and the outer end of which is provided with an annular fiange I03, and with a hexagonal portion I04 which forms a wrench grip. The nut I02 is secured to the sleeve in such manner that the sleeve is free to rotate independently of the nut, but is constrained to move longitudinally in response to rotation of the nut by means of a screw I05, the head of which cooperates with an annular shoulder I06 formed within the nut, and the threaded end of which is screwed into and pinned fast to the sleeve. A dial I01 provided with a number of markings 29, 30, etc. representing wheel diameters in inches is fastened to the flange I03 of the sleeve shifting nut, and indicates by its position in relation to a mark I08 provided on the inside of the casing adjacent one edge of the dial, the position to which the nut should be turned to cause the contacts to operate at the desired speeds for any particular wheel diameter. The nut is arranged to be clamped in its adjusted position by means of a semicircular clamping member I09 (see Fig. 8) which is bolted by means of bolts I I0 and III to a semi-circular boss I00a formed in the easing I00 at the outer end of the hole NH, and which is effective when the bolts are tightened to frictionally engage the helical threads of the nut in a manner to securely clamp it in any position to which it is adjusted.

The linkage which connects the centrifuge arms 22 and 23 with the rods I3 and I6 is so designed that the force acting on the springs I9 and 20 varies approximately in direct proportion to the car speed, and with the springs I9 and 20 arranged in the manner pointed out hereinbefore so that the spring I9 does not come into play until an axle speed of 218 revolutions per minute is obtained, a characteristic curve similar to the curve II5 shown in Fig. 9 is obtained for one particular proportioning oi the parts. Referring to Fig. 9, the curve IE5 shows the relationship between the travel in degrees of the cam segments and axle revolutions per minute, and indicates the cam segment travel corresponding to axle revolutions per minute for wheel diameters of from 36 /2 to 29 inches at four different car speeds, namely 11 /2 miles per hour, 17 /2 miles per hour, 26 miles per hour, and miles per hour. It will be noted that the amount of cam segment travel necessary to compensate for changes in wheel diameter is different for each different speed, these differences being due to the fact that the cam segment travel is a function of the forces set up by the centrifuge arms, the mechanical advantage of the linkage, and the opposing force due to the springs I9 and 20. Since the amount of cam segment travel necessary to compensate for changes in wheel diameter is diiiferent for each difierent speed, the angles at which the various cam plates are beveled are so chosen that the differences in the number of degrees of travel of each of the four cam segments which are necessary to cause the contacts to operate at the same car speed for a change in wheel diameters can simultaneously be effected by moving the cam sleeve longitudinally by means of the sleeve adjusting nut I82. For example, to compensate for a change in wheel diameters from 36 /2 to 29 inches a difference of 3 in the amount the cam segment 56a travels is required, 7 /z in the amount the cam segment 59L travels, 4 in the amount the cam segment 55c travels, and 7% in the amount the cam segment d travels, and the cam plates for the particular proportioning of the parts represented by the curve have been so beveled as to provide this difference when the sleeve is moved longitudinally between its two extreme positions by rotating the nut between its two extreme positions. It will be apparent, of course, that when it is desired to effect a change in the adjustment of the position of the cam sleeve to compensate for a change in wheel diameter, this change can be effected by merely loosening the bolts H0 and III to release the sleeve adjusting nut 502, rotating this nut to the point in which the marker on the dial I0! corresponding to the new wheel diameter is opposite the marker I08 on the casing I00, and then again tightening the bolts H and ill to reclamp the nut I02 in its adjusted position.

One advantage of a governor constructed in accordance with my invention is that the governor after it is once adjusted at the factory can be shipped to a customer and the customer can then place the governor on any car which he sees fit regardless of the diameter of the wheels of the car, the necessary adjustment to adapt the governor to the different size wheels being quickly and conveniently made in the manner previously described.

Another advantage of a governor constructed in accordance with my invention is that as the wheels wear, thus decreasing their diameters and hence tending to decrease the car speeds at which the contacts of the governor will operate, the contacts can be made to operate at their original speeds by adjusting the sleeve adjusting nut in the manner previously described.

Although I have herein shown and described only one form of speed responsive devices 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. In a speed governor, a member which is rotated to different positions in response to changes in the speed of a body and which is movable longitudinally between two positions, contact mechanism, and means secured to said member for operating said contact mechanism at an angular position of said member which depends upon its longitudinal position.

2. In a speed governor which is adapted to be driven from a car axle, a plurality of contacts, a centrifuge, a plurality of cam segments operated by said centrifuge and cooperating with said contacts to selectively operate said contacts, and means for simultaneously varying the angular positions at which said segments operate said contacts in a manner to permit said contacts to be operated at the same car speed for different axle speeds to compensate for different wheel diameters.

3. In a speed governor, a member which is rotated to different positions in response to changes in speed and which is movable longitudinally between two positions, a cam segment secured to said member, contact mechanism operated by said segment through the medium of means which cooperates with the cam face of said segment, and means secured to said segment and effective in response to changes in the longitudinal position of said member to vary the angular position of said cam segment at which said contact mechanism becomes operated.

4. In a speed governor, a first member which. is rotated to different positions in response to changes in speed and which is movable longitudinally to different positions, a cam segment secured to said first member by means whereby said segment can be rotated to different angular positions relative to said first member, a second member biased to one position and adapted to be moved to another position by engagement with said cam segment, and means on said cam segment for varying the angular position of said first member at which said second member engages said cam segment in response to longitudinal movement of said second member.

5. In a speed governor, a first member which is rotated to different positions in response to changes in speed and which is movable longitudinally between two positions, means for moving said first member longitudinally between its two positions, a plurality of cam segments secured to said first member, a plurality of other members one cooperating with each of said cam segments and each arranged to be moved from one position to another position by engagement with the associated cam segment, and means on each cam segment for varying the angular position of the segment at which it engages the associated one of said other members in response to longitudinal movements of said first member, whereby by moving said first member longitudinally the speeds at which said other member are operated may be simultaneously varied.

6. In a speed governor, a first member which is rotated to different positions in response to changes in speed and which is movable longitudinally between two positions, a cam segment secured to said first member, and a second member arranged to be moved from one position to another by engagement with the cam face of said segment, said segment being provided at the one end of its cam face with an edge which is beveled at an angle to the axis of said first member, whereby by moving said first member longitudinally the angular position of said cam segment at which it engages said second member may be varied.

7. In a speed governor, a first member which is rotated to different positions by a centrifuge in response to changes in speed and which is movable longitudinally between two positions, a plurality of cam segments adjustably secured to said first member in such manner that said segments may be rotated to different angular positions relative to said first member, a plurality of other members one cooperating with each of said cam segments and each arranged to be moved from one position to another by engagement of the associated cam segment with such other member, and a plurality of cam plates one secured to each cam segment adjacent one end of the cam surface of the segment and each provided with an edge which is beveled at an angle to the axis of said first member and which forms a continuation of the cam surface of the associated segment, all of said edges being beveled at a different angle, whereby by moving said first member longitudinally the speeds of said centrifuge at which said other members are operated may be simultaneously varied in a manner to maintain a constant difference between the operating speeds.

8. In a speed governor, a first member which is rotated to different positions by a centrifuge in response to changes in speed and which is movable longitudinally between two positions, a plurality of cam segments adjustably secured to said first member in such manner that said segments may be rotated to different angular positions relative to said first member, a plurality of other members one cooperating with each of said cam segments and, each arranged to be moved from one position to another by engagement of the associated cam segment with such other member, said cam segments each having the edge which first moves into engagement with the associated other member so shaped with reference to the characteristics of said centrifuge that by moving said first member longitudinally proportionate changes in the speed of said centrifuge at which said other members become operated may be made.

9. In combination, centrifuge means driven from a car axle at a speed which depends upon the diameter of the car wheels, a cam sleeve connected with said centrifuge means and rotated between two positions by said centrifuge means in response to changes in the speed of said car, a cam segment secured to said sleeve, contact mechanism operated by said cam segment through the medium of means which is engaged by the segment, means for moving said sleeve longitudinally between two positions, and means secured to said segment in such manner that by shifting said sleeve longitudinally the angular position at which said segment becomes effective to operate said contact mechanism can be continuously varied in a manner to compensate for differences in the diameter of car wheels.

10. A governor comprising a cam shaft, centrifuge means for rotating said shaft between two positions, a cam sleeve constrained to rotate between two positions and slidable longitudinally along said shaft to two positions, cam segment having a relatively wide cam face secured to said cam sleeve, a cam plate secured to said cam segment adjacent one end of its cam face and forming a continuation of its cam face, and a rocker pivotally supported adjacent said cam segment and biased to one position and provided with means cooperating with said cam segment for rotating said rocker to another position by engagement with the cam surface of said cam segment, said cam plate being beveled at an angle to the axis of said sleeve whereby by moving said sleeve longitudinally to different positions, the speed of said centrifuge at which said rocker is moved to its other position may be varied.

11. A governor comprising a cam shaft, centrifuge means adapted to be driven from a car axle connected with said shaft for rotating said shaft between two positions, a cam sleeve constrained to rotate in response to rotation of said shaft but movable longitudinally between two positions, a plurality of cam segments adjustably secured to said cam sleeve in such manner that said segments may be rotated to different angular positions relative to said shaft, a cam plate secured to each cam segment adjacent one end of its cam face and forming a continuation of its cam face, and a plurality of rockers one cooperating with each cam segment and each arranged to be moved from one position to another by means which is engaged by the cam face of the associated cam segment, said cam segments being adjusted to cause said rockers to be operated at different car speeds and said cam plates being so shaped with reference to the characteristics of said centrifuge that by sliding said sleeve longitudinally to different positions the car speeds at which. all of said rockers become oper ated for car wheels having different diameters may be maintained constant.

12. A governor comprising a cam shaft, centrifuge means adapted to be driven from a car axle connected with said shaft for rotating said shaft between two positions, a cam sleeve constrained to rotate in response to rotation of said shaft but movable longitudinally between two positions, a

plurality of cam segments adjustably secured to said cam sleeve in such manner that said segments may be rotated to different angular positions relative to said shaft, a cam plate secured to each cam segment adjacent one end of its cam face and forming a continuation of its cam face, a plurality of rockers one cooperating with each cam segment and each arranged to be moved from one position to another by means which is engaged by the cam face of the associated cam segment, said cam segments being adjusted to cause said rockers to be operated at different car speeds and said cam plates being so shaped with reference to the characteristics of said centrifuge that by sliding said sleeve longitudinally to different positions the car speeds at which all of said rockers become operated for car wheels having different diameters may be maintained constant, and means for moving said sleeve longitudinally calibrated in a manner to enable said contacts to be set for wheels of any particular diameter.

13. A governor comprising a cam shaft, centrifuge means adapted to be driven from a car axle and comprising a pair of balanced crossed centrifuge arms pivotally mounted at their point of intersection and operatively connected by means of links with a pair of opposed pistons which are biased by means of springs in directions to exert forces on said arms in opposition to the centrifugal foroe acting thereon, the one said spring being lighter and having a flatter rate than the other and having a slight initial compression with the centrifuge at rest and the other spring being of such length that it will not exert a biasing force on said centrifuge arms until a predetermined speed is reached and said links being so arranged that the force which is exerted onsaid springs by the centrifuge arms varies approximately in direct proportion to the car speed, means for connecting one of said pistons with said cam shaft in such manner that said shaft will be rotated between two positions by said centrifuge means, a first member constrained to rotate with said cam shaft and slidable longitudinally along said shaft to two positions, a cam segment secured to said first member, and a second member arranged to be moved from one position to another by engagement with the cam face of said cam segment, said segment being provided at one end of its cam face with an edge which is so shaped with respect to the characteristics of said centrifuge that by moving said sleeve longitudinally said second member may be made to operate at the same car speed on cars having different diameter wheels.

14. A governor comprising a cam shaft, centrifuge means adapted to be driven from a car axle and comprising a pair of balanced crossed centrifuge arms pivotally mounted at their point of intersection and operatively connected by means of links with a pair of opposed pistons which are biased by means of springs in directions to exert forces on said arms in opposition to the centrifugal force acting thereon, the one said spring being lighter and having a flatter rate than the other and having a slight initial compression with the centrifuge at rest and the other spring being of such length that it will not exert a biasing force on said centrifuge arms until a predetermined speed is reached and said links being so arranged that the force which is exerted on said springs by the centrifuge arms varies approximately in direct proportion to the car speed, means for connecting one of said pistons with said cam shaft in such manner that said shaft will be rotated between two positions by said centrifuge means, a cam sleeve constrained to rotate in response to rotation of said shaft but movable longitudinally between two positions, a plurality of cam segments adjustably secured to said cam sleeve in such manner that said segments may be rotated to different angular positions relative to said sleeve, a cam plate secured to each cam segment adjacent one end of its cam face and forming a continuation of its cam face, and a plurality of rockers one cooperating with each cam segment and each arranged to be moved from one position to another by means which is engaged by the cam face of the associated cam segment, said cam segments being adjusted to cause said rockers to be operated at different car speeds and said cam plates being so shaped with reference to the characteristics of said centrifuge that by sliding said sleeve longitudinally to different positions the car speeds at which all of said rockers become operated for car wheels having different diameters may .be maintained constant.

15. In a governor, centrifuge means adapted to be connected with and driven from a car axle, a cam shaft connected with said centrifuge means and adapted to be rotated between two positions by said centrifuge means, a cam sleeve mounted on said cam shaft for longitudinal sliding movement between two positions and constrained to rotate with said cam shaft, a plurality of cam segments secured to said cam sleeve in different angular positions, contact mechanism associated with each cam segment adapted to :be operated at a predetermined car speed by means which is engaged by the cam face of the associated cam segment, a casing disposed adjacent one end of said sleeve and provided with a threaded hole which aligns axially with said sleeve, a hollow nut screwed into said hole and receiving one end of said sleeve, means for connecting said nut with said sleeve in such manner that said sleeve is free to rotate relative to said nut but that rotation of said nut will move said sleeve longitudinally along said shaft, a dial secured to said nut and provided with markings corresponding to wheel diameters, said cam segments each having one end of its cam face so shaped with respect to the characteristics of said centrifuge means and the markings on said dial being so located that said contacts may all be made to operate at the same car speed regardless of the diameter of the wheels on the axle from which the centrifuge is driven by turning said nut to the position in which the marking on said dial corresponding to the diameters of the wheels on the axle is opposite a marking provided on said case.

16. In a speed governor including a centrifuge, a plurality of contacts, separate operating mechanism for each contact, said mechanisms being individually adjustable for operating the associated contact at any selected centrifuge speed falling within a predetermined range of speeds, the range of speeds for each contact being different from that for the remaining contacts, and means for simultaneously adjusting all of said operating mechanisms independently of the associated individual adjustments to simultaneously change the selection of the centrifuge speeds at which said contacts become operated in a manner to maintain a constant relation between the centrifuge speeds at which the several contacts become operated.

HERBERT L. BONE.

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