US2716467A

US2716467A - Elevator car flexible guide clamp safety

Info

Publication number: US2716467A
Application number: US313551A
Authority: US
Inventors: Clarence R Callaway
Original assignee: WATSON ELEVATOR Co Inc
Current assignee: WATSON ELEVATOR Co Inc; WATSON ELEVATOR COMPANY Inc
Priority date: 1952-10-07
Filing date: 1952-10-07
Publication date: 1955-08-30
Anticipated expiration: 1972-08-30

Description

Aug. 30, 1955 c. R. CALLAWAY 2,716,467

ELEVATOR CAR FLEXIBLE GUIDE CLAMP SAFETY Filed Oct. 7, 1952 4 Sheets-Sheet 1 0 0 0 0 0 o 74 0 l) o 0 3a 40 40 o V INVENTOR. (Z4PEA/CEE64AMMV A r TOP/W5) Aug. 30, 1955 c. R. CALLAWAY ELEVATOR CAR FLEXIBLE GUIDE CLAMP SAFETY 4 Sheets-Sheet 2 Filed Oct. 7, 1952 w NE 3 A fiih 3 wk MN 0% vm 1 vm \0 m H m wk 3 mm NW .A A MR Q T A v W QM.N\\ 1 w P m Q P O m N\\ E I vm mm NW v, M 5 Mn N N L e m m w C T IDA. g P. P m 6 w r NQ E rum PFC wm 1f m Aug. 30, 1955 c. R. CALLAWAY 2,716,467

ELEVATOR CAR FLEXIBLE GUIDE} CLAMP SAFETY Filed Oct. 7, 1952 4 Sheets-Sheet 5 74 o 0 74 o o a a 0 o o F5 5 INVENTOR.

F) TTOP/VE) Aug. 30, 1955 c. R. CALLAWAY 2,716,467

ELEVATOR CAR FLEXIBLE GUIDE CLAMP SAFETY Filed Oct. 7, 1952 4 Sheets-Sheet 4 United States Patent ELEVATOR CAR FLEXIBLE GUIDE CLAMP SAFETY Application October 7, 1952, Serial No. 313,551

14 Claims. (Cl. 18790) My invention relates to an improved elevator car flexible guide clamp safety and more particularly to a safety device for elevator cars in which the elevator car is brought 8 to an emergency stop by applying a braking action upon the guide rails in the event the elevator exceeds a predetermined speed of downward movement for any cause.

Safety devices for stopping the elevator car in the event of excessive downward speed are known to the art. These devices usually take the form of a spring-actuatedbrake adapted to clamp the guide rails. If the clamping pressure exercised by the spring is too weak, the car willnot be brought to a stop. If the clamping pressure is too great, the car may stop too suddenly, with attendant damage to apparatus or injury to the passengers of the car.

One object of my invention is to provide a flexible guide clamp safety device for elevator cars in which heavy spring pressure may be employed and yet insure that the car is brought to a stop in such gradual manner as not to injure apparatus or passengers.

Another object of my invention is to provide a flexible guide clamp safety in which a constant retarding force will be applied even though the elevator is traveling at high speeds.

Another object of my invention is to provide a flexible guide clamp safety which insures the alignment of the clamping jaws with the guide rails at all times.

A further object of my invention is to provide a flexible guide clamp safety which will not suddenly jam or grip the guide rails to bring the car to a sudden halt with the attendant danger.

Another object of my invention is to provide a flexible guide clamp safety having clamping jaws which will align themselves correctly with the guide rails at all times independent of imperfections in the guide rails.

Other and further objects of my invention will appear from the following description.

In general, my invention contemplates the provision of a pair of jaw levers biased to a fixedposition by a stout spring. Adjacent the guide rails I position a pair of wedge-shaped clamping jaws adapted to be moved into engagement with the guide rails when it is desired to brake the elevator car. Between each pair comprising one of the jaw levers and one of the wedge-shaped jaws I provide a plurality of balls disposed in a ball carrier. I provide means to position the ball carrier correctly with respect K) the jaws in all positions. The wedging action between the guide rails and the jaw levers is resisted by the stout spring, the thrust being transmitted through the balls. The arrangement is such that when the clamping jaws have reached their limit of motion, a constant retarding force will be exerted upon the guide rails by the springs which bias the jaws. The balls insure that the wedge-shaped clamping jaws will always align them- .selves properly with the surfaces of the guide rails, the

thrust being transmitted through spherical surfaces.

,be attached to the car at the top.

I provide a convenient hydraulic means for releasing the clamping action as it has taken place.

In the accompanying drawings which form part of the instant specification and which are tobe read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

Figure. 1 is a diagrammatic view showing an elevator installation equipped with a guide clamp safety.

Figure 2 is a side elevation of the bottom of an elevator car equipped with a flexible guide clamp safety of my invention.

Figure 3 is a bottom plan view of the flexible guide clamp safety shown in Figure 2.

Figure 4 is a sectional view drawn on an enlarged scale viewed along the line 44 of Figure 2.

Figure 5 is a sectional view drawn right side up, on an enlarged scale, taken along the line 5-5 of Figure 3.

Figure 6 is a sectional view drawn on an enlarged scale and viewed right side up taken along the line 66 of Figure 3.

Figure 7 is a sectional view drawn on an enlarged scale viewed along the line 77 of Figure 2.

Figure 8 is a diagrammatic view showing the mode of hydraulically releasing the spring pressure which actuates the clamping jaws.

Figure 9 is a sectional view drawn on an enlarged scale viewed along the line 8-8 of Figure 4.

Referring now to Figure 1, the elevator car 10 is adapted to be raised and lowered by a hoisting cable 12 through the medium of a hoisting motor 14, the other end of the cable 16 being provided with a customary counterweight 18. The safety assembly is indicated generally by the reference numeral 20 and is secured to the bottom of the elevator car 10. It is to be understood, of course, that the guide clamp safety may, if desired,

An endless flexible member, such as a Wire rope 22, is positioned upon a pair of sheaves 24 and 26 and extends through the elevator shaft from top to bottom throughout the amplitude of travel of the elevator. A friction clamp 28 is secured to the safety rope 22. The clamp 28 is attached to the elevator car by a springpositioned arm 30. A tail rope 32 extends from the friction clamp 28 to the guide clamp safety assembly. A governor 34 is adapted to be driven by the rotation of the sheave 26. As the elevator moves upwardly and downwardly, the safety rope is moved along with the elevator car through the friction clamp 28 and the connecting arm 30. When the elevator exceeds the downward veloc ity to which the governor 34 is set, the governor will stop the movement of the sheave 26, thus immobilizing the safety rope 22. The downward motion of the car relative tothe stationary friction clamp 28 will cause a tug or pull to be exerted on the tail rope 32. The tug or pull of the tail rope sets the guide clamp safety, as will be described more fully hereinafter.

Referring now to Figure 2, the elevator car 10 is mounted upon a suitable stout framework 36 which may comprise a pair of I-beams 38 to which frame members 40 are secured in any appropriate manner, there being one frame 40 at each side of the elevator car adjacent each guide rail 42. I pivot a pair of

levers

44 and 46 intermediate their ends to each frame 40 by means of

hinge pins

48 and 50. The outer end 52 of the lever '44 and the outer end 54 of the lever 46 are disposed on the opposite sides of the flange 56 of the guide rail 42. The other end 58 of lever 44 and the other end 60 of lever 46 are provided with openings through which a bolt 62 passes. The ends of the bolt are threaded to receive

nuts

64 and 66. A spring 68 is positioned between the

lever ends

58 and 60 and serves to bias these lever ends outwardly. A bearing disk 70 is positioned between one end of spring 68 and the lever end 58. A similar bearing disk 72 is positioned between the other end of the spring 68 and the lever end 60. The position of the nuts 64 and 66 determines the initial position of the lever jaws 52 and S4.

Rotatably mounted in suitable bearings carried by the frames 40 I position a pair of

shafts

74 and 76, these shafts running the full length of the assembly. A crank 78 is keyed to each end of a shaft 74 for rotation therewith and a similar crank 80 is keyed to each end of crank 76 for rotation therewith, as can be seen by reference to Figure 4. Each

lever jaw

52 and 54 is formed with an inclined surface 82 which diverges fromthe guide rail flange 56 in a downward direction. A clamping jaw 34 is carried by the end of crank 78 through a link 86. A ball carrier 88 is positioned between the clamping jaw 84 and the jaw lever surface 82. A plurality of thrust transmitting balls 90 are carried by the ball carrier 88. The ball carrier is connected to the crank 78 through a link 92.

The construction on the other side of the guide rail 56 is symmetrical to that just described. A clamping jaw 94 positioned on the other side of the flange 56 of the guide rail corresponds to the clamping jaw 84. The link 96 corresponds to link 86 and connects the clamping jaw 94 to the end of crank 80. The ball carrier 98 corresponds to the ball carrier 88 and the balls 100 correspond to the balls 90. The link 102 connects the ball carrier to the crank 80 intermediate its ends.

It will be observed, by reference to Figure 4, that the ball carrier 88 is displaced downwardly from the upper edge of the inclined surface 82 through a convenient distance. The clamping jaw 84 is displaced downwardly from the upper edge of the ball carrier 88 through this same distance. To move the parts to their clamping position, that is, with the clamping jaw 84 horizontally in alignment with the lever jaw 52 the ball carrier will have to move through a certain distance while the clamping jaw 84 will have to move through twice this distance. To maintain the parts in their proper relationship to preclude sliding displacement of the ball carrier I position the

links

92 and 86 such that the ball carrier will move at one-half the speed of the clamping jaw in an upward direction. This insures the parts will be maintained in their correct position so that the thrust will be transmitted through all of the balls 90 at the maximum thrust.

Referring now to Figure 9, the end of each lever jaw is provided with a plate 104 secured thereto by a plurality of bolts 106 to prevent displacement of the clamping

jaws

84 and 94 and the

ball carriers

88 and 98 longitudinally of the assembly. The surface 108 of the clamping jaw 84 which contacts the guide rail flange 56 is provided with a plurality of grooves 110 into which grease and dirt which might be present on the guide rail flange surface can be scraped when contact between the clamping jaws and the guide rail flange is made.

A sprocket wheel 112 is keyed to the shaft 74 for rotation therewith. I key a sprocket wheel 114 to the shaft 76 for rotation therewith. These sprocket wheels are connected by a crossed drive chain 116 to insure that

shafts

74 and 76 will always rotate in opposite directions. A crank 118 is keyed to shaft 74 for rotation therewith. An angle iron 120 is carried by the I beams 38 and secured thereto in any appropriate manner. The flange 122 of the angle iron 120 carries a rod 124 to the end of which I swivelly mount a guide block 126. A socket block 128 is pivotally mounted to the end of crank 118. A rod 130 extends from the socket block 128 through guide block 126. Around the rod I position a spring 132. The thrust of spring 132 will rotate the shaft 74 in a counterclockwise direction as viewed in Figure 7 and in a clockwise direction as viewed in Figure 4. The drive chain 116, therefore,

will rotate the sprocket wheel 114 in a clockwise direction as viewed in Figure 7 and hence will rotate the shaft 76 in a clockwise direction as viewed in Figure 7. As viewed in Figure 4, however, the shaft 76 will appear to rotate in a counterclockwise direction. Accordingly, the crank 78 will rotate in a clockwise direction as viewed in Figure 4 and the crank will rotate in a counterclockwise direction as viewed in Figure 4.

The end of frame 40 is provided with a stop lug 134 to position the cranks in a convenient non-clamping position with sufficient clearance between the clamping jaw surfaces and the guide rail flange 56. The spring 132 serves to maintain the parts in this position. Secured to shaft 76 for rotation therewith I provide a sheave 136 around which the tail rope 32 is wound. The end of the tail rope is secured to the sheave by a clamp 138, as can be seen by reference to Figure 7. Whenever the elevator car moves downwardly at a velocity in excess of that to which the governor 34 is set, the governor will stop the safety rope 22. The downward motion of the car with respect to the stationary safety rope will tug upon the tail rope 32. When the tail rope 32 is pulled it will rotate the sheave 136 in the direction of the arrow shown in Figure 7, that is, in a counterclockwise direction This will rotate the shaft 76 in a counterclockwise direction and hence the sprocket wheel 114 in a counterclockwise direction, as viewed in Figure 7. This will rotate the sprocket wheel 112 in a clockwise direction as viewed in Figure 7 through the crossed chain 116. These directions of rotation under the influence of the tug upon the tail rope 32 will be in the direction of the arrows in Figure 4. Shaft 74, in rotating in a counterclockwise direction, will lift the clamping jaw 84 and the ball carrier 88 at half the speed of travel of the clamping jaw. Similarly, the clockwise rotation of the shaft 76 will, through the crank 80 and the connecting

links

96 and 102, lift the clamping jaw 94 at a predetermined speed and will lift the ball carrier 98 at half this speed. Due to the wedgeshaped construction of the clamping jaws they will be carnmed inwardly, gripping the clamp 56 of the guide rail. It is understood, of course, that the clamping jaws on both ends of the assembly will be carnrned inwardly to grip the side rails at each end of the elevator car. The clamping thrust will be transmitted through the balls and to the

respective lever jaws

52 and 54 tending to thrust the lever jaws outwardly. This outward motion 01' the

lever jaws

52 and 54 will, as can readily be seen by reference to Figure 3, force the lever ends 58 and 60 inwardly against the action of the heavy spring 68. In this manner a constant predetermined clamping pressure is applied to the guide rails providing a constant retarding force which will smoothly and quickly bring the elevator car to a stop. The clamping

jaws

84 and 94 are clamped by thrust transmitted through the

balls

90 and 100. Any irregularities in the guide rails will be readily accommodated for due to the fact that the bearing surfaces between the jaws 84 and 94' are spherical by reason of the spherical shape of the balls. This permits the jaws to align themselves at all times. The connection of the jaws and the ball carriers to the

cranks

78 and 80 insures the correct positioning of the ball carriers with respect to the jaws in all positions.

In order to prevent the fouling of the suspension cables of the elevator by having the hoisting motor feed out .the cables after the car is stopped by my flexible guide clamp safety I position a switch 140 for controlling the motor 14 upon an appropriate support 142 carried by the beams 38. An actuating crank 144 for the switch 140 is keyed to shaft 76 for rotation therewith. Whenever the tail rope 32 rotates the shaft 76 the actuating crank 144 will stop the motor.

After the elevator has been stopped it can only be freed by moving the car upwardly. This usually involves shunning the switch 140 and hoisting the eat to free the safety device. I I I In Figure 8 I have shown a modification of my 111-. vention which will enable the car to be freed without reversing its direction. The lever end 58 is formed with a hydraulic cylinder 73 having a piston 71 posttioned therein. The bolt 62 is secured to the lever end 60 by the nuts 66, in a manner similar to the construction shown in Figure 6. The lever end 58, however, is provided with an opening 59 through which the bolt 62 passes. A stop nut 61 is carried by the bolt normally to determine the outward position of movement of the lever end 58 under the influence of spring 68. The bolt 62 extends outwardly through the cylinder end 75 and is secured to the piston 71 by means of a nut 77. An appropriate reservoir 79 for hydraulic fluid is provided A hand pump 81 operable by a hand lever 83 is adapted to pump fluid from the reservoir 79 past check valve 85 through pipe 87 to the space 89 between the cylinder end 75 and the top of the piston 71. This will move the piston to the left, compressing the spring 68 between the

ends

60 and 58 of the

levers

46 and 44. This movement of the lever ends 60 and 58 toward each other under hydraulic pressure against the action of spring 68 will move the

lever jaws

52 and 54 away from each other, relieving the clamping action. As soon as the clamping thrust of the spring is relieved, the spring 132 will rotate the

shafts

74 and 76 to bring the

cranks

78 and 80 to the position shown in Figure 4, thus freeing the safety device from its clamping position. small conduit 91 having an appropriately small crosssectional area provides for the leakage of fluid from the cylinder back to the reservoir 79. This fluid is forced through the bleeding conduit 91 by the spring pressure 68 and gradually allows the spring pressure to move the lever ends outwardly until they rest against the stop nuts 66 and 61. This, again, places my safety device in a position to operate. The restoration of the parts of the safety assembly to their nonoperating position automatically restores the elevator to operating condition since the switch 140 will be moved to a position completing the motor circuit so that the elevator may again operate. I have found that an amplitude of motion of the piston 71 of two inches is ample to provide for releasing movement of the parts.

It will be seen that I have accomplished the objects of my invention. I have provided an elevator car flexible guide clamp safety which will furnish a constant retarding force for an elevator car even though it may be traveling at very high speeds when the safety operates. I have provided means for insuring the aligning of the clamping jaws with the guide rails irrespective of any local misalignment of the guide rails. I provide means for insuring correct positioning of the ball carrier with respect to the stationary and movable jaws in all positions. My flexible guide clamp safety is simple in construction and certain in operation. The clamping pressure may be readily adjusted in a convenient and expeditious manner. The governor may be placed in any convenient location and, if desired, the friction clamp for the safety rope may be placed at the bottom of the car instead of the top of the car, as is customary in the prior art. My construction is such that all danger of seizing the rail by the clamping jaws and freezing them thereto is eliminated. In this manner injury to occupants of the car and damage to the apparatus is avoided. If desired, means may readily be provided for freeing the assembly after it is clamped without moving the car upwardly.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the 'spirit of my invention. therefore to be understood that my invention is not to be limitedto 'the specific details shown and described.

'Having thus described my invention, what'I claim is: i 1. In an'elevator car'flexible guide-clamp safety assembly a car, guide rails forthe car, a pair of levers carried by the car pivoted intermediate their ends, a spring positioned between the inner pair of lever ends urging them away from each other, means for limiting the movement of the inner lever ends under the influence of the spring, means for positioning the outer lever ends'on'opposite sides of a guiderail and spaced therefrom, a pair of shafts, means for mounting the shafts on the car for rotation, an arm secured to each shaft for rotation therewith, means forconnecting the shafts to rotate'in opposite directions, a bearing element carrier positioned between one outer lever end and the guide rail, another bearing-element carrier positioned between the other outer lever end and the guide rail, bearing elements carried by the carriers, means for attaching respective carriers to respective arms-,a clamping block positioned between one carrier and the guide rail, another clamping block positioned between the other carrier and the guide rail, means for attaching the clamping blocks to respective arms, means responsive to a predetermined speed of descent of the elevator car for rotating the shafts to lift the bearing element carriers and the clamping blocks whereby to clamp the guide rail between the clamping blocks, the construction being such that the clamping thrust will move the outer ends of the levers away from each other against the action of the spring.

2. An elevator car flexible guide clamp safety assembly as in claim I, in which said outer lever ends are formed with surfaces which lie along planes diverging from each other in a downward direction, the bearing elements being adapted to engage said surfaces.

3. An elevator car flexible guide clamp safety assembly as in claim 1, in which said bearing elements comprise balls.

4. An elevator car flexible guide clamp safety assembly as in claim 1, in which said clamping blocks are wedge-shaped.

5. An elevator car flexible guide clamp safety assembly as in claim 1, in which said means for attaching the carriers -to the arms comprise links pivotally secured to the arms and to the carriers.

6. An elevator car flexible guide clamp safety assembly as in claim 1, in which said means for attaching the clamping blocks to respective arms comprise links pivotally connected to respective clamping blocks and arms.

7. An elevator car flexible guide clamp safety assembly as in claim 1, in which each of the attaching means for the carriers is attached to its arm between the arm shaft and the point of attachment to the arm of the clamping block.

8. An elevator car flexible guide clamp safety assembly as in claim 1, in which the distance of the point of attachment of each clamping block to its arm from the center ofits shaft is twice the distance of the point of attachment of the carrier to the arm from the shaft center.

9. An elevator car flexible guide clamp safety assembly as in claim 1, including means for biasing the shafts to rotate the arms to move the bearing element carriers and the clamping blocks away from clamping position.

10. An elevator car flexible guide clamp safety assembly as in claim 1, in which said means responsiveto a predetermined speed of descent of the car for rotating the shafts includes a tail rope, a sheave secured to one of the shafts for rotation therewith, said tail rope being positioned about said sheave, a safety rope, means for controlling the speed of the movement of the safety rope and means for attaching the tail rope to the safety rope.

11. An elevator car flexible guide clamp safety assem- It' is bly as in claim 1, in which said elevator car is provided with a switch and means responsiveto the rotation of. one of said shafts for operating said switch. x 12. An elevator car flexible guide clamp safety 'assem bly as in claim 1, inwhich said means for limiting the movement of the inner lever ends under the influence of the spring includes a ,rod extending axially of the spring and passing through the lever ends and nuts threadedly carried by the rods outboard of the lever ends.

13. An elevator car flexible guide-clamp safety assembly as in claim 1, in which said means for limiting the, movement of the inner lever ends under the influence of the spring includes a rod extending axially of the spring and passing through the lever ends, nuts threadedly carried by the rods outboard of the lever ends, a cylinder carried by one of the lever ends, a piston positioned in said cylinder, means for seeuringhone end of the rod to the piston and means for introducing fluid under pres-. sure into the piston whereby to move the inner lever ends toward each other against the action of the spring to release the guide clamp safety from clamped position.

carried by one of the lever ends, a piston positioned in said cylinder, means for securing one end of the rod to the piston, means for introducing fluid under pressure into the piston whereby to move the inner lever ends toward each other against the action of the spring to 7 release the guide clamp safety from clamped position and means for releasing fluid pressure from the cylinder.

, References Cited in the file of this patent UNITED STATES PATENTS 756,811 Baldwin Apr. 12, 1904 974,414 Mohnike Nov. 1, 1910 2,150,373 Hymans Mar. 14, 1939