US2740358A

US2740358A - Propelling mechanism for ballast handling machines

Info

Publication number: US2740358A
Application number: US184534A
Authority: US
Inventors: Frank H Philbrick
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-09-13
Filing date: 1950-09-13
Publication date: 1956-04-03
Anticipated expiration: 1973-04-03

Description

A ril 3, 1956 F. H. PHILBRICK 2,740,353

PROPELLING MECHANISM FOR BALLAST HANDLING MACHINES Filed Sept. 13, 1950 7 Sheets-Sheet l -April 3, 1956 F. H. PHlLBRlCK 2,740,353

PROPELLING MECHANISM FOR BALLAST HANDLING MACHINES Filed Sept. 13, 1950 7 Sheets-Sheet 2 A ril 3, 1956 F. H. PHILBRICK 2,740,358

PROPELLING MECHANISM FOR BALLAST HANDLING MACHINES Filed Sept. 13, 1950 7 Sheets-Sheet 3 April 3, 1956 F. H. PHILBRICK PROPELLING MECHANISM FOR BALLAST HANDLING MACHINES 7 Sheets-Sheet 4 Filed Sept. 13, 1950 A ril 3, 1956 F. H. PHILBRICK 2,740,358

PROPELLING MECHANISM FOR BALLAST HANDLING MACHINES Filed Sept. 13, 1950 7 Sheets-Sheet 5 "r Sheet sSheet e bw 8w. N NN llllllll llhllLm I; l lllllllllll lllv c A ril 3, 1956 F. H. PHILBRICK PROPELLING MECHANISM FOR BALLAST HANDLING MACHINES Filed Sept. 13, 1950 April 3, 1956 F. H. PHILBRICK PROPELLING MECHANISM FOR BALLAST HANDLING MACHINES 7 Sheets-Sheet '7 Filed Sept. 13, 1950 United States Patent PROPELLING MECHANISM FER BALLAST HANDLING MACHINES Frank H. Philhrick, Evanston, iii.

Application September 13, 1950, Serial No. 184,534

14 Claims. (Cl. res-3e The invention relates to propelling mechanism for ballast handling machines.

One object of the invention is to provide mechanism for propelling a ballast handling or cleaner which is usually mounted on a wheeled car or truck, while the machine is being advanced to dig ballast from the road bed, and the traction of the car wheels on the rails of a track is insuificient for propulsion of the machine against the resistance of the ballast.

Another object of the invention is to provide improved propelling mechanism for a machine which is operable on a railway track, which includes devices for gripping a rail between them for insuring the advance of the machine in the performance of work on the ballast.

Another object of the invention is to provide means for causing the rail-gripping shoes to pass around electrical rail bonds between rail sections of the track to prevent damage to said bonds.

Another object of the invention is to provide mechanism for controlling the raising of the gripping device for high speed transportation of the machine along the railway track and the lowering of the gripping devices to operative level with the track rails, and for controlling the gripping devices to release the rails during their lifting and lowering movements.

Other objects of the invention will appear from the detailed description.

The invention consists in the several novel features hereinafter described and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a side elevation of a ballast cleaning machine equipped with the invention, parts being broken away;

Fig. 2 is a plan view of the gearing for driving the several mechanisms of the machine;

Fig. 2 is a section taken on line 2 2 of Fig. 2;

Fig. 3 is a side elevation of the apparatus for raising and lowering the rail-gripping devices;

Fig. 4 is a plan view of one of the lifting devices shown in Fig. 3;

Fig. 5 is a diagrammatic view of the system for controlling the raising and lowering apparatus for lifting and lowering and for rendering the gripping devices operative and inoperative to grip the rail;

Fig. 6 is a plan view of rail-gripping devices and the mechanism for imparting reciprocatory strokes thereto;

Fig. 7 is a plan view of one of the rail-gripping devices and the pitman and eccentric connected thereto, parts being shown in section;

Fig. 8 is a side elevation of the parts shown in Fig. 7;

Fig. 9 is a section taken on line 9-9 of Fig. 7;

Fig. 10 is a rear end view of one of the rail-gripping devices.

Fig. 11 is a section taken on line 11--11 of Fig. 9, the rail being shown in section;

Fig. 12 is a detail section of the air speed control valves;

Fig. 13 is a detail section of one of the sequence control valves.

"ice

The invention is exemplified in a machine for cleaning ballast, which usually comprises a car or truck frame provided with wheels adapted to travel on the rails of a railway track, rotary digger devices 20 for feeding ballast from sides of the track to bucket elevators 21, cleaning devices for the ballast, conveyors for delivering the cleaned ballast back onto bed of the railway track and separately discharging the material removed from the ballast, all of which may be of any suitable construction and are exemplified in Letters Patent No. 2,272,429, and therefore the details of said apparatus are not herein more fully described. The truck frame comprises longitudinal beams 17 and cross beams 18 rigidly secured together.

In this type of machine, the load upon the diggers and their slow advance into the ballast, are too great for the propulsion of the machine while it is working in the ballast by traction of the car or truck wheels on the rails, and to insure the advance of the machine for progressive ly digging the ballast at an efiicient speed, the invention provides propelling mechanism which includes shoes for intermittently gripping the head of the rail between and devices for advancing the machine while it is so gripped. The truck or car frame is provided with carrying Wheels 22 and 23 on

axles

24 and 25 for supporting the machine for travel on the rails of a track. The driving mechanism includes gearing for high speed travel when the machine is not handling ballast.

As internal combustion motor 26 is mounted on the truck frame and its output shaft is adapted to drive a clutch 27 which drives a variable speed-transmission gearing 28. A set of sprocket chains 30 driven by sprockets 29 extend around and drive a set of sprocket wheels 31 on a countershaft 32 which is journalled in a gear box 33. A transverse shaft 35 is journalled in gear box 33 and is driven from shaft 32 by a bevel gear 36 on shaft 32 and a mating bevel gear 37 on shaft 35. The front axle 25 between traction wheels 23 is adapted to be driven for high speed travel of the machine along the railway track while the diggers 20 are not in use, by a multiplesprocket 39 on shaft 35, sprocket chains 40 driven by sprocket 39, a sprocket 42 and a manually operable clutch which includes a driven clutch member 44 on sprocket 42 and a slidable clutch collar 45 which is slidably splined to axle 24 and engageable with member 44.

The gear box 33 has journalled therein a shaft 46 which is parallel to and driven from shaft 32 by a gear 47 on shaft 32 and meshing with a gear 48 on shaft 46. Each of the shafts 32 and 46 is adapted to drive one of the digger devices 20 by means of a double sprocket 49 on each of said shafts, sprocket chains 50, a double sprocket 51 driven by chains 50 on a longitudinal shaft 51 which is journalled on the truck frame, a double sprocket 52 fixed to or integral with sprocket 51, sprocket chains 53 driven by sprocket 52 and a double sprocket 54 driven by chains 53 and fixed to drive the longitudinal shaft 55 of one of the digger devices 243. Each shaft 55 is provided with sprockets 56 for driving one of the bucket elevators for lifting the ballast fed thereto by one of the diggers which includes a shell 57 provided with a toothed cutting edge 58. Each shaft 55 is supported by a pair of arms 59 and 69 for vertical movement relatively to the truck frame. Arms 59 and 60 are pivotally movable on shafts 55, respectively, for raising and lowering the digger units into and out of working position.

In propelling the car or truck for advancing the ballast feed devices into the ballast at the sides of the track, the resistance of the ballast is so great that the traction between the car wheels and the rails of the track will be ineflicient in propelling the machine or may fail to propel it at the slow and constant rate of advance desired for continuous progress of the feed devices. The invention pro: vides propelling mechanism which includes rail gripping and propelling devices for advancing the car while the machine is being operated to dig or load the ballast. Preferably a pair of transversely aligned gripping devices is provided at the front and a similar pair is provided toward the rear of the car. These rail gripping and propelling devices are alike in construction and the front pair is operated from a cross shaft 79 which is mounted in bearings 3 on cross beams 18 of the truck frame, and the rear pair is operable from a cross shaft 80 which is similarly mounted.

The rear shaft 80 is driven by a sprocket 62 on shaft in gear box 33, a chain 63 driven by sprocket 62, a sprocket loose on shaft 80 and driven by chain 63, a clutch member 65 on sprocket 64, and a clutch collar 66 slidably splined to shaft for selectively operating said shaft. The front shaft 79 is driven by a sprocket 67 on shaft 8%, a chain 68 driven by sprocket 67 and a sprocket 69 driven by chain 68 and fixed to shaft 79.

Each rail gripping and propelling device comprises: a bracket 83 which is adapted to travel over one of the rails of the railway track; an arched bracket M which straddles said rail; a pair of levers 85 fulcrumed on pins 86 which are supported in bracket 84 at opposite sides of said rail; a pair of toggle links 87, each pivotally connected at its rear end by a pin 93 to the front end of a lever a pin 89 pivotally connecting the front end of both links 87 to the bracket 83; a pair of shoes 99 having faces for gripping the head of a track rail between them, and each mounted on a forked lug 90 which is supported by and connected for lateral pivotal movement on the rear end of a lever 85. Each gripping device is operated to alternately grip the rail for intermittently and alternately advancing the car while the rail is gripped and to release the rail for advancing the gripping device along the rail by an eccentric 91 which is mounted for rotary adjustment on a flanged eccentric 92 which is keyed to shaft and a pitman 93 which is provided with a band 94 which extends around eccentric 91 and is journalled on a roller bearing 95 on said eccentric, and is pivotally connected by a horizontal pin 96 to the forked upper front end of bracket 83. The eccentrics 91 on one shaft 80 are set to impart forward strokes to the pitmen operated thereby While the eccentrics 91 on the other shaft 80 are set to impart backward strokes to the pitrnen operated thereby, so that the pairs of gripping devices will be alternately actuated to advance the machine.

The bracket 83 and the bracket 84 of each propelling and gripping device are connected for relative longitudinal movement by a connection which comprises a two-way operable piston 98 which is slidable in a cylinder 99 and fixed to a stem 1% which is secured in a lug 101 which is pivoted on connecting pin 89, which is movable with a bracket 83. Each cylinder 99 is connected at its rear end by' a pin 103 to a screw eye 102 which is adjustably locked in a U-shaped extension 104 which is integral with a bracket 84. Air under pressure between piston 98 and the front end of piston cylinder 99 will urge bracket 84 forwardly to move the fulcrum pins 86 of levers forwardly relatively to bracket 83 and urge the shoes against the sides of the head of the rail. Air under pressure between piston 98 and the rear end of the cylinder 99 will shift bracket 84, the fulcrum pins 86 and levers 85 rearwardly relatively to bracket 83 and cause the shoes 90 to be locked away from the sides of the rail head. Pipes 1.65 and 106 are connected to the opposite ends of each cylinder 99 for alternately supplying air under pressure and exhausting it from the opposite ends of each cylinder 99. The delivery and exhaust of air through these

pipes

105 and 106 for alternately rendering the gripping devices operative and inoperative with respect to the track rail are hereinafter described.

The operation of each propelling and gripping device will be as follows:

When air under pressure is present between the piston 98 and the front end of cylinder 99 and the eccentric 94 is rotated, pitman 93 during the rearward stroke of eccentric 91 will exert a rearward thrust on pin 96 and bracket 83. Connector pin 89 will exert rearward thrust on the connected ends of toggle links 87, and through pins 33 exert outward pressure on the front ends of levers 85 which will fulcrum on pins 86 in bracket 84. The rear ends of levers 85 will be forced to press the shoes 90 against the sides of the head of the rail between them. During the forward strokes of the eccentrics 91, the brackets 83 will be locked to the rail and the eccentrics 91 rotating in the eccentric bands 94 which are held against rearward movement by pins 96, will move the shafts 79 and 8t) bodily forward a distance corresponding substantially to the stroke of the eccentric. In this manner the machine will be advanced by power which drives the eccentric and through the-gripping of the rail by the shoes 90. During the forward stroke of each eccentric 91, the pitman 93 will exert a forward pull on bracket 83 and connecting pin 89 will exert an inward pull on the toggle links 87. This pull on the links 87 will exert an inward pull on the front ends of levers 85 and an outward movement on the rear ends of said levers so that the pressure of shoes 89 against the rail will be released to. permit the entire gripping device to slide along the rail during each forward stroke of the eccentric 91. The bodily advances of

shafts

79 and 80 will alternately cause the gripping devices to grip the rails in an advanced position during each succeeding cycle of eccentric 91. The eccentrics on the shafts 3i), and '79 respectively, are set for alternately advancing the machine so that while the eccentrics 91 on one of the shafts 79 and 8.0 are propelling the machine, the eccentrics 91 on the other shaft will move one pair of gripping devices forwardly relatively to the track rails.

For the purpose of shifting the gripping devices into and out of rail-engaging relation to render them inoperative while they are raised for the speedy transportation of the machine along the railway track and to clear rail bonds between sections of the track rails, the levers 85 are shiftable to spread shoes 90 away from the rail. When air under pressure is supplied through pipe 105 to cylinder 99 and exhausted through pipe 106, the piston 98 will be subjected to pressure which will cause cylinder 99 to urge bracket 84 forwardly, hold the toggle links 87 in the position shown in full lines in Fig. 7 and urge the gripping shoes against the rail. When air is exhausted through pipe 105 from cylinder 99 and air under pressure is delivered into said cylinder by pipe 196, said cylinder will be shifted backwardly relatively to the piston 98. This shift of said cylinder will move bracket 34 rearwardly relatively to the connector pin 39 and move rearwardly the fulcrum pins 86 for levers 85. This will cause levers 35 and toggle links 87 to swing into the dotted line position shown in Fig. 7 so that .the shoes 90 will be spaced laterally from the sides of the rail head sufficiently for raising and lowering the rail-gripping devices and for clearing rail bonds on the outer side face of the rail head The raising and lowering means for each rail-gripping unit comprises: an air cylinder 11%) which is stationar-ily mounted on a longitudinal beam 111 of the supporting structure on the car, a piston 1 12 slidable in cylinder 110, a stem 113 on said piston, and a pair of

cables

114 and 115 guided by sheaves 116 on the supporting structure, and connected to the outer end of a stern 113 and respectively connected to

brackets

84 and 83 of the rail-grip ping unit. When air under pressure is delivered via apipe 117 into one end of cylinder 111) and exhausted vialpipe 118 from the opposite end, the piston 112 will be shifted to support the rail-gripping unit connected thereto in its operative position for gripping the rail. When air under pressure is delivered into the opposite end of cylinder by 118 and exhausted therefrom via pipe 117, piston 112 will be shifted to raise the rail gripping unit and support it in its raised position. During the raising and lowering of a gripping unit, each pitman 9.3 which is pivoted to bracket :83 can swing on .one eccentric 91. in

connection with this raising and lowering mechanism, the air in each cylinder 99 is controlled to insure the release of the gripping shoes for permitting the raising and lowering movement in co-ordinated relation with the operation of piston 112 in cylinder 110 by means hereinafter described.

The air to cylinders 99 is also controlled to release the shoes 90 when they are in operative relation to the tracks and a rail bond 120 between rail sections is encountered.

The control means for this purpose comprises: a shoe 122 which is slidably mounted for tranverse movement in a bracket 124 which .is mounted on a beam of the supporting structure of the car, a spring 125 for yieldingly urging the shoe against the side of the rail head, a cam plunger 126 on the stern of shoe 122, and a spring-closed valve 123 which is mounted on and provided with a lever 127 which is operable to open said valve when shoe 122 is shifted by a bond 120. A pipe 128 is connected to deliver air under pressure to valve 123 to control means hereinafter described for each cylinder 99 and piston 98 when a rail bond 125 is to be cleared. The gripping device after it has passed the rail bond 12% is rendered operable to grip the rail.

The control means for raising and lowering the railgripping units includes a hand operable valve 140, a pipe 141 conducts air under pressure from a supply line 160 to valve 149, a pipe 142 connects a port in the piston of valve 140 to pipe 117 and is connected to a branch pipe 143 in which a sequence control valve 144 is included. Pipe 143 is connected to a port in a pilot valve 145. A pipe 146 connects a port in valve 140 and a port in a two-position pilot valve 145, and a branch 147 of pipe 146 in which a sequence control valve 148 and an air speed control valve 149 are included, connects pipe 146 and a pipe 118. A pipe 150 connects a port in pilot valve 145 and pipe 105 which is connected to one end of a pair of cylinders 99 of the gripping devices. Air speed control valve 149 restricts and regulates the exhaust from the rear end of cylinders 1111 while lowering the gripping devices and permitting free flow of air under pressure to said cylinders during the lifting of said devices. Each air sequence valve permits free flow of air under pressure in one direction and restricts the reverse flow of exhaust. A pipe 151 connects a port in pilot valve 145 and a pipe 106 which is connected to the opposite end of a pair of cylinders 99. Pilot valve 145 has an exhaust port 152. A pipe 129 which is connected to a pair of spring-closed valves 123 is connected to a pipe 153 which includes a bleed valve 154 and is connected to a cylinder 155 which contains a spring-pressed plunger 156 having a stem 157 with a cam for operating the lever of a valve 158. Valves 158 are connected by a pipe 159 to the supply line 160 and control the flow of air to the pilot valve 145, and are connected by a pipe 161 to one end of the casing of the pilot valve 145 for shifting the piston of the pilot valve against the force of a spring 162.

The operation of the controls for the gripping devices will be as follows: I Assuming the gripping devices to be raised for highspeed travel of the car as illustrated in Fig. 5, air pressure is maintained in one end of the cylinders 110 to hold pistons 112 in position to support the gripping devices raised above track level. Air under pressure will be applied to hold pistons in said position via pipe 160, pipe 141, valve 149, pipe 146, sequence control valve 148, speed control valve 147 under free flow, and pipe 118 in one end of cylinders 110 while air from the opposite end of cylinders 119 will be connected to exhaust via pipe 117, pipe 142, a port in valve 149 and exhaust 117 Air under pressure will also be maintained in one end of the cylinders 99 of the gripping devices to hold them in railreleasing position via valve 149, pipe 146, a port in pilot valve 145, pipe 151 and pipes 196 and the opposite end of cylinders 99 will exhaust via pipes 105 and 150, a port in pilot valve 145 and exhaust 152.

When the gripping devices are to be lowered into operative elevation at the sides of the rail, the handle of valve 140 is shifted to its alternative position. Air under pressure then passes via pipe 141, a port in valve 140, pipe 142 and pipe 117 into the end of lifting cylinders 110 for shifting pistons 112 to the gripping devices. Exhaust from the lower opposite end of cylinders 110 is controlled by speed control valve 149 and retarded fiow through sequence valve 148 via pipes 147 and 146, a port in valve 140 and air exhaust in 117 b in valve 140.

While the machine is being advanced by the eccentrics and gripping devices, it is necessary to spread the gripping shoes 99 to pass around rail bonds 120. As one of the gripping devices approaches a rail bond, the spring-pressed shoe 1.22 associated with said device slides over and is shifted outwardly by the rail bond. The cam 126 on shoe 122 will operate the valve 123 associated with said shoe and cause air under pressure to flow from pipe 160 via a pipe 128, said valve 123, pipe 129, pipe 153 in which bleed valve 154 is included, to cylinder 155. The piston 156 will be shifted in cylinder 155 and operate valve 158 for the flow of air via pipe 159, valve 158, pipe 161 to pilot valve 145, which will be operated to its alternative position. Air will then be exhausted from the front end of cylinder 99 of the gripping device adjacent the rail bonds, via pipe 165, pipe 150, a port pilot valve 145 and exhaust port 152, while air under pressure will be conducted to the opposite end of said cylinder via pipe 141, valve 149, pipe 143 in which sequence valve 144 is included, a port in pilot valve 145, pipe 151 and pipe 196. The piston 98 in the cylinder 99 will then be operated to shift bracket 84 and levers into position to spread the shoes so they will clear the rail bond 124 This spread position of the shoes 90 will be retained for a predetermined period until they have passed the rail bond 121) and the air in cylinder 155 has been exhausted through bleed valve 154. When the shoe 122 passes over and beyond the rail bond 121), valve 123 will cut ofi" air under pressure to pipe 153. Air will be slowly exhausted from cylinder 155 by the bleed valve 154, whereupon plunger 157 on piston 156 in cylinder 155 will be spring-retracted and operate valve 158 to cut oil the fiow of air to the valve piston of pilot valve 145. The pilot valve 145 will then be returned to its normal position by spring 162. Air will be supplied via pipe 143, a port in pilot valve 145 and pipes 150 and to cylinder 99 to shift the shoes 90 of gripping devices into operative relation with the rail. Air will be exhausted from the rear ends of cylinder 99 via pipes 106 and 151, and exhaust 152 in valve 145. The gripping devices are thus individually and automatically controlled to pass around the rail bonds so the latter will not be broken or damaged by the rail-gripping shoes 99.

When high speed travel of the machine is desired for transportation while the ballast handling mechanism is idle, the gripping devices are raised above the rails. This lifting is controlled by the manually operable valves 140. The operating levers of said valves will be shifted into their alternative position whereupon air under pressure will flow via pipe 141, a port in valve 140, pipe 146 in which air sequence valve 145 and speed control valve 147 are included, and pipe 118, into one end of cylinders.

110, while air is exhausted from the opposite ends of said cylinders via pipe 117, pipe 142, pipe 143 in which sequence valve 144 is included, and a port in the pilot valve 145 to exhaust 152. The gripping devices are spread away from the rails to free them so they can be lifted. Air under pressure will enter one end of cylinders and shift pistons 112 for raising the gripping devices and pass via pipe in which sequence valve 143 and speed control valve 149 are included into said cylinders while air exhausts from the opposite ends of the cylinders via pipes 117 and 142 and exhaust port 117 in valve 140. Air under pressure also passes after the gripping devices have been lowered into the rear end of cylinders' 99 for releasing the shoes 911 from the rail via pipe 106,

pipe 151, pilot valve 145, pipe 146, valve 140 and pipe 141. This action is delayed until the gripping devices have been lowered. The air will be exhausted from the rear ends of cylinders 99 via pipes 106 and 151, a port in valve 145, pipe 14-6 and exhaust port 117* in valve 140.

During propulsion of the machine by the rail gripping devices, shafts will be continuously driven by sprocket 62, chain '30., sprocket 64 and clutch a and as and shaft 7-9 will be driven from shaft Si by sprocket 67, chain 68 and sprocket 69 on shaft '79. hrough clutch s5 and 66 the operation of the gripping devices may be select-ively controlled.

Shafts

79 and 89 will continuously rotate the front and rear pairs of eccentrics 91 and operate the pitman 93 which operate the gripping devices. The eccentrics on shafts 79 and 8b are timed to alternately operate the pitrnan for advancing the machine so that while eccentrics of shaft 89 are operating the rear gripping devices to advance the machine, the eccentrics on shaft 79 will be operating the other pair of gripping devices to move forwardly relatively to the rails.

When it is desired to transport the machine from place to place, the gripping devices will be raised and released from the rails as before described. The machine may then be selectively propelled on the railway track by power derived through the variable speed transmission 28 and from shaft 35, sprocket wheel 39, chain 49, sprocket wheel 42, clutch 44 and 45 and axle 25 and the traction wheels 23 thereon.

In order to disengage each shoe 122 from the rail when the machine is propelled by the traction wheels, each bracket 124 on which said shoe and its associated valve is supported, is slidably connected by bolts and slots 170 to a plate 171 which is fixed to a beam 17, and an air cylinder 172 with a two way piston 173 is adapted to shift bracket 124 and shoe 122 laterally away from the rail. Air under suitable control supplied by a pipe 174 to one end of cylinder 172 will hold piston 173 to render the shoe operative on the rail, and air supplied by pipe 175 to the opposite end of cylinder 172 will shift piston 173 and bracket 124 so that the shoe E22 will be spaced from the outer side of the rail. Pipe 173 may be connected to pipe 117 and pipe 175 connected to pipe 118, so that when the gripping device is raised the bracket and shoe 122 will be moved away from the railand when the gripping device is lowered the shoe 122 will be moved to engage the rail.

The invention is not to be understood as restricted to the details set forth since these may be modified within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention what i claim as new and desire to secure by Letters Patent is:

l. Propelling mechanism for a machine supported on a wheeled structure adapted to travel on the rails of a railway track and provided with apparatus for handling ballast from the road bed, comprising: a power unit on the structure, crank elements driven by. the unit and mounted on the structure, a pair of gripping devices each including a pair of levers at the sides of and for gripping a rail, means for supporting each device for movement along the rail, pitmen operable by said crank elements, connections operable by the pitmen for swinging the levers to grip the rail and exert thrust to propel the structure and alter ately swinging the levers to release the rail for advance of the structure and levers along the rail, the pitmen being operated for alternately gripping and releasing a rail, and selectively operable means for retaining the levers in non-gripping relation at the sides of the rails while the pitmen continue to be operated by said shaft.

2. Propelling mechanism for a machine supported on a wheeled structure adapted to travel on the rails of a railway track and provided with apparatus for handling ballastfrom the road bed, comprising: a power unit on the structure, crank elements driven by the unit and mounted on the structure, a pair of gripping devices each including a pair of levers at the sides of and for gripping a rail, means for supporting each device for movement along the rail, pitmen operable by said crank elements,

connections operable by the pitmen for swinging thelevers to grip the rail and exert thrust to propel the structure and alternately swinging the levers to release the rail for advance of the structure and levers along the rail, the pitmen being operated for alternately gripping and releasing a rail, and selectively operable pneumatic means for retaining the levers in non-gripping relation at the sides of the rails while the pitmen continue to be operated by said shaft.

3. Propelling mechanism for a machine supported on a wheeled structure adapted to travel on the rails of a railway track and provided with apparatus for handling ballast from the road bed, comprising: a power unit on the structure, crank elements driven by the unit and jour nalled on the structure, a pair of gripping devices each including a pair of levers provided with shoes for gripping a rail, means for supporting each device for movement along the rail, pitmen operable by said crank elements, means operable by the pitmen for swinging the levers to grip the rail and propel the structure and alternately swinging the levers to release the rail for advance of the supporting means and levers along the rail, means movable with the structure engageable with a rail and operable by a bond between rail sections, and means controlled by said last named means for shifting the levers to clear the bond until the levers have travelled beyond the bond.

4. Propelling mechanism for a machine supported on a wheeled structure adapted to travel on the rails of arailway track and provided with apparatus for handling ballast from the road bed, comprising: a power unit on the structure, crank elements driven by the unit and journalled on the structure, a pair of gripping devices each including a pair of levers provided with shoes for gripping a rail, means for supporting each device for movement along the rail, pitmen operable by said crank elements, means operable by the pitmen for swinging the levers to grip the rail and propel the structure and alternately swinging the levers to release the rail for advance of the supporting means and levers along the rail, means movable with the structure engageable with a rail and operable by a bond between rail sections, and fluid pressure means controlled by said last named means for shifting the levers to clear the bond until the levers have travelled beyond the bond.

5. Propelling mechanism for a machine supported on a wheeled structure adapted to travel on the rails of a railway track and provided with apparatus for handling ballast from the road bed, comprising: a power unit on the structure, crank elements driven by the unit and journalled on the structure, a pair of gripping devices each including a pair of levers provided with shoes for gripping a rail, means for supporting each device for movement along the rail, pitmen operable by said crank elements, means operable by the pitmen for swinging the levers to grip the rail and propel the structure and alternately swinging the levers to release the rail for advance of the supporting means and levers along the rail, a shoe mounted on the structure for engaging a rail and operable by a rail bond between the rail sections, and means controlled by the shoe for operating the levers to clear the bond until the shoe has travelled beyond the bond.

6. Propelling mechanism for a machine supported on a wheel structure adapted to travel on the rails of a railroad track and provided with apparatus for handling ballast from the road bed, comprising: a power unit on thestructure, a pair of transverse shafts, mechanism for driving the shafts from the power unit, a pair of crank elementson each shaft, pairs of devices operable by the crank elements on the shafts respectively for gripping rails at opposite sides of the track, means for supporting each 9 gripping device for movement along the rails, and means operable by the crank elements for positively operating the gripping devices to grip the rails and exerting thrust to propel the structure and for alternately releasing the rails for advance of the structure, the crank elements on the shafts respectively being operated and connected for operating gripping devices in pairs for alternately gripping and releasing rails atthe opposite sides of the track.

7. Propelling mechanism for a machine supported on a wheel structure adapted to travel on the rails of a railroad track and provided with apparatus for handling ballast from the road bed, comprising: a power unit on the structure, a pair of transverse shafts, mechanism for driving the shafts from the power unit, a pair of crank elements on each shaft, pairs of rail-gripping devices for rails at the opposite sides of the track, pairs or" pitmen operable by the crank elements on each of the shafts and operatively connected to such devices respectively, means for supporting each gripping device for movement along the rails, and means operable by the pitmen for positively operating the gripping devices to grip the rails and exerting thrust to propel the structure and for alternately swinging the levers to release the rails for advance of the structure and levers along the rails, the crank-connections and pitmen being operated and connected for operating gripping devices in pairs for alternately gripping and releasing the rails at the opposite sides of the track.

8. Propelling mechanism for a machine including a truck provided with wheels adapted to travel on the rails of a railway track and power-driven mechanism for driving said Wheels, comprising: a power-driven crank element, a pitman operated by said element, a pair of toggle links connected to and operated by the pitman for movement along the rail, and a pair of levers for gripping a rail, pivoted to the links respectively, operable along the rail by the links and supported to swing into gripping engagement with the rail by rearward thrust on the links from the pitman and to release the rail by forward pull on the links from the pitman.

9. Propelling mechanism for a machine including a truck provided with Wheels adapted to travel on the rails of a railway track and power-driven mechanism for driving said wheels, comprising: a power-driven crank element, a pitman operated by said element, a pair of toggle links connected to and operated by the pitman for :ovement along the rail, a pair of levers for gripping a rail, pivoted to the links respectively, operable along the rail by the links, and supported to swing into gripping engagement with the rail by rearward thrust on the links from the pitman and to release the rail by forward pull on the links from the pitman, and means for holding the levers and links to release the rail during rearward thrust of the pitman.

10. Propelling mechanism for a machine including a truck provided with wheels adapted to travel on the rails of a railway track and power-driven mechanism for driving said wheels, comprising: a power-driven crank element, a pitman operated by said element, a pair of toggle links connected to and operated by the pitman for movement along the rail, and a pair of levers for gripping a rail, pivoted to the links respectively, operable along the rail by the links, and supported to swing into gripping engagement with the rail by rearward thrust on the links from the pitman and to release the rail by forward pull on the link from the pitman, and pneumatic means for holding the levers and links to release the rail during rearward thrust of the pitman.

11. Propelling mechanism for a machine including a truck provided with wheels adapted to travel on the rails of a railway track, and power-driven mechanism for driving said wheels, comprising: a power-driven crank element, a pitman operated by said element, a supporting structure connected to the pitman for movement along a rail, a pair of toggle links pivoted on the structure and movable along the rail by the pitman, and a pair of levers for gripping the rail, pivotally supported on the structure and pivoted to the links respectively, and operable to grip the rail by rearward thrust on the links from the pitman and to release the rail by forward pull on the links from the pitman.

l2. Propelling mechanism for a machine including a truck provided with wheels adapted to travel on the rails of a railway track, and power-driven mechanism for driving said wheels, comprising: a power-driven crank element, a pitman operated by said element, a supporting structure connected to the pitman for movement along a rail and including relatively movable brackets, a pair of toggle links pivoted on one of the brackets of said structure and movable along the rail by the pitman, and a pair of levers for gripping the rail, pivotally supported on the other bracket of said structure and pivoted to the links respectively, and operable to grip the rail by rearward thrust on the links from the pitman and to relase the rail by forward pull on the links from the pitman.

l3. Propelling mechanism for a machine including a truck provided with wheels adapted to travel on the rails of a railway track, and power-driven mechanism for driving said wheels, comprising: a power-driven crank element, a pitman operated by said element, a supporting structure connected to the pitman for movement along a rail and including relatively movable brackets, a pair of toggle links pivoted on one bracket of the structure and movable along the rail by the pitman, and a pair of levers for gripping the rail, pivotally supported on the other bracket of the structure and pivoted to the links respectively, and operable to grip the rail by rearward thrust on the links from the pitman and to release the rail by forward pull on the links from the pitman, and means for relatively shifting the brackets and the links and the levers for holding the levers to release the rail during backward thrust on the pitman and links. I

14. Propelling mechanism for a machine including a truck provided with wheels adapted to travel on the rails of a railway track, a power-driven mechanism for driving said wheels, comprising: a power-driven crank element, a pitman operated by said element, a supporting structure connected to the pitman for movement along a rail and including relatively movable brackets, a pair of toggle links pivoted on one of the brackets of the structure and movable along the rail by the pitman, and a pair of levers for gripping the rail, pivotally supported on the other bracket of the structure and pivoted to the links respectively, and operable to grip the rail by rearward thrust on the links from the pitman and to release the rail by forward pull on the links from the pitman, and pneumatic means between the brackets for holding the lever and links to release the rail during backward thrust of the pitman.

References Cited in the file of this patent UNITED STATES PATENTS 360,230 Lapage Mar. 29, 1887 850,018 Kohlmyer Apr. 9, 1907 2,391,657 Tavelin Dec. 25, 1945 2,473,109 Schneider June 14, 1949 FOREIGN PATENTS 11,114/ 1846 England Feb. 27, 1846 334/1898 England Feb. 19, 1898