US2858908A

US2858908A - Cable gripper

Info

Publication number: US2858908A
Application number: US357859A
Authority: US
Inventors: Temple Robert
Original assignee: Mine Safety Appliances Co
Current assignee: MSA Safety Inc
Priority date: 1953-05-27
Filing date: 1953-05-27
Publication date: 1958-11-04
Anticipated expiration: 1975-11-04

Description

Nov. 4, 1958 R. TEMPLE 7 2,853,908

CABLE GRIPPER Filed May 2'7, 1953 2 Sheets-Sheet 1 I INVEN TOR. Poss/e7 7221091 11,:

7am, an! Jay/Z44 6 a? fro Ys' United States Patent 2,858,908 CABLE GRIPPER Robert Temple, Swissvale, Pa., assignor, by mesne assignments, to Mine Safety AppliancesCompany, Pittsburgh, Pa., a corporation of Pennsylvania This invention relates to apparatus for gripping a cable, and more particularly to means forstopping the longitudinal movement gripper. I a K In some cases it is desirable that a longitudinally moving cable or the like he stopped suddenly and positively after it has. traveled a predetermined distance. Sometimes this must be done automatically or in a location that is quite inaccessible. i I f It is among the objects of this invention to provide a cable gripper which is self-contained, compact and durable, which is positive andinstantaneous in action, which can be operated in a remote location automatically, which is dependable in operation, which is designed for use under water, and which does not weaken the cable at the gripping point.

In accordance with this invention a block is provided with a passage through it for a cable moving through the block. The block also is provided with a barrel spaced from one side of the passage and with. a slot connecting that side with the side of the barrel. A clamp is slidably disposed in the slot and has a front end beside the passage and a rear portion extending partway across the barrel. A wedge is slidably mounted in the barrel for engaging the rear portion of the clamp. Means, preferably explosively actuated, are provided for driving the wedge ahead so that it will push the clamp forward into the cable passage to clamp a cable therein against the opposite side of the passage. Suitable bleed holes and openings are provided so that when the block is used in water, the water will not interfere with the operation of the clamp and wedge. a

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which- Fig. l is a plan view of my cable gripper;

Fig. 2 is an end View;

Fig. 3 is a combined vertical section and side view taken on the, line IIIIII of Fig. 1;

Fig. 4 is a horizontal section taken on the line IVIV of Fig. 3, but with the wedge shown in elevation;

Fig. 5 is a vertical section taken on the line V+V of Fig. 1; and

Fig. 6 is a horizontal section, similar to Fig. 4, but showing the gripper after it has been operated, with the clamp and wedge in elevation. i

Referring to the drawings, a heavy rectangular metal block 1 has screws 2 extending down through it near its four corners. The lower ends of the screws connect the block to a suitable support (not shown)' by which the block is held in position. through the block near one corner is a passage 3 for loosely receiving a line or cable 4 that can be moved through the passage. At one side of this passage the block is provided with a barrel 6, preferably cylindrical, extending lengthwise through the block. The side of cable passage 3 next to the barrel is connected by a vertical slot 7 with the barrel, through which the slot of a cable traveling through the Extending vertically preferably extends. The slot also extends through the top and bottom of the block.

Slidably mounted in this slot is a clamp 8 in the form of a solid metal bar having its front end extending along the open side of the cable passage. As shown in Fig. 4, the clamp normally is spaced far enough from the opposite side of the passage to offer no interference with movement of the cable through the passage. The clamp has a rear portion which extends only part way across the barrel, but, as shown in dotted lines in Fig. 2, the parts of the clamp above and below the barrel preferably extend farther back for a purpose that will be described presently. In other words, the clamp is U- shaped so that the central part of the rear portion of the clamp is provided with a recess 9, the inner wall of which is located inside the barrel. The clamp is held in its normal or retracted position by one or more shear pins 10 inserted in horizontal bores in the block above and below the barrel. The pins are held in place by screws 11 threaded in the enlarged outer ends of the bores. The pins preferably extend entirely through the clamp and into-the block beyond it.

Extending into or through the recess 9 in the back part ofthe clamp is the front end of a wedge 13 that has a transversely curved outer surface slidably engaging the .side of the barrel. The rear end of the Wedge is integral with a cylindrical piston 14 that also fits slidably in the barrel and holds the wedge in place. Thevertical inner wall of the clamp recess most suitably has the same inclination transversely as the adjoining flat surface of the wedge so that they will fit fiat against each other as shown in Fig. 4. It will be seen that as the piston is moved ahead in the barrel, toward the clamp, it will push the wedge farther through the clamp recess and thereby cause the clamp to shear pins 10 and move forwardinto cable passage 3 to clamp the cable against the opposite side of the passage as shown in Fig. 6. The front end of the clamp preferably is provided with a vertically extending groove 15 that receives part of the cable when the clamp is driven ahead. The wedge is driven ahead with enough force to cause the clamp to compress the cable to a smaller diameter and thereby hold it so tightly that it cannot move through the block. The hard strands of the cable are forced into the softer material of the clamp and block, and the cable retains approximately its full strength where it is compressed. The wedge is jammed between the back part of the clamp and the wall of the barrel so that the clamp cannot reduce its pressure against the cable. As the clamp straddles the wedge,

cable.

It is preferred to drive the piston and wedge forward in the barrel by means of an explosive actuated device. Most suitably, as shown in Fig. 4, this device includes a sleeve 17 that is screwed into the threaded enlarged rear end of the barrel. The front end of the sleeve is closed by a thin disc 18 that is sealed in place. Inside the sleeve there is a plunger 19, the front end of which engages the disc. The rear end of the plunger is enlarged to form a cup 21 that slidably engages the inner surface of the sleeve. The rear end of this cup fits tightly over the front end of a tubular breech block 22 that is held in the rear end of the sleeve by means of a threaded collar 23. The cup is filled with powder 24 that can be ignited by an electric squib 26, the wires 27 to which extend out through the back of the breech block to a suitable source of electricity. When the current is turned on, the squib ignites the powder which thereupon explodes and causes theplunger to rupture the thin disc 18 and drive piston 14 toward the opposite end of the barrel, as shown in Fig. 6. I

To enable this gripper to be used under water satisfactorily, a number of bleed holes are formed in'the block to allow the water to escape from the cable passage and barrel so that it will not interfere with the operation of the device. As shown in Fig. 1, one bleed hole is in the form of a slot 30 that extends vertically through the block and into the space between the clamp and piston 14. This prevents water from being trapped in thatspace. To likewise prevent water from being trapped in the cable passage, opposite sides of the passage are provided with recesses 31 that extend through the top and bottom of the block. Rapid escape of water from the passage is facilitated by

drilling holes

32 and 33 horizontally into the block to connect with recesses 31 about midway between their ends.

In cases where the cable above the block is likely to be bent or swung back and forth a great deal, it is desirable to prevent the bending from being concentrated right at the top of the block where the bending might be sharp enough to eventually break the cable. Accordingly, a flexible sleeve 35 of rubber or the like and of suitable length is fitted loosely around the cable directly above the block. As shown in Fig. 5, the sleeve has a flange 36 at its lower end which is clamped between a plate 37 and a recessed collar 38. The collar is held in place by screws 2. In order to prevent the plate from covering the upper ends of the vertical bleed holes, it is spaced from the top of the block by means of washers 39 on the screws.

Assuming, for exaample, that the cable is moving upward through the block, the cable can be stopped at any desired instant by the closing of a switch in the circuit of the electric squib 26 in the firing mechanism. The wedge then will be driven ahead immediately to force the clamp tightly against the cable. The moment the cable is jammed between the clamp and block its upward movement ceases.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A cable gripper comprising a block provided with a cable passage therethrough and with a barrel spaced from one side of the passage, the axes of said passage and barrel lying in substantially parallel planes, the barrel being provided with a slot connecting said adjacent side of the passage with the side of the barrel, a clamp slidably dis-. posed in said slot and having a front end beside said passage and having a rear portion extending part way across said barrel, a wedge slidably mounted in the barrel for engaging said rear portion of the clamp, whereby when the wedge is moved across the clamp it will push the clamp forward into said passage to clamp a cable therein against the opposite side of the passage, and a shear pin in the block extending into the clamp to hold the clamp in place until the wedge exerts a predetermined pressure against it.

2. A cable gripper comprising a block provided with a cable passage therethrough and with a barrel spaced from one side of the passage, the axes of said passage and barrel lying in substantially parallel planes, the barrel being provided with a slot connecting said adjacent side of the passage with the side of the barrel, a clamp slidably disposed in said slot and having a front end beside said passage and having a rear portion extending part way across said barrel, a wedge in the barrel for engaging said rear portion of the clamp, a piston slidably mounted in the barrel at one end of the wedge for pushing the wedge across. the clamp so that the clamp will be moved forward into said passage to clamp 21 cable therein against the opposite side of thepassage, and fluid pressure means connected to the barrel for forcing the piston toward the clamp.

3. A cable gripper comprising a block provided with a cable passage therethrough and with a barrel spaced from one side of the passage, the axes of said passage and barrel lying in substantially parallel planes, the barrel being provided with a slot connecting said side of the passage with the adjacent side of the barrel, a clamp slidably disposed in said slot and having a front end beside said passage and having a rear portion extending part way across said barreha wedge slidably mounted in the barrel for engaging said rear portion of the clamp, a sleeve connected to the barrel at the rear end of the wedge, a thin disc clamped between the inner end ofthe sleeve and said block, a plunger in the sleeve having one end adjacent the disc, a cup at the opposite end of the plunger, explosive powder in the cup, a breech block secured to the outer end of the sleeve, and remotely controlled means for igniting said powder to drive the plunger through the disc, whereby to move the wedge forward across the clamp so that'the clamp will be moved forward into said passage to clamp a cable therein against the opposite side of the passage.

4. A cable gripper comprising a block provided with a cable passage therethrough and with a barrel spaced from one side of the passage, the axes of said passage and barrel lying in substantially parallel planes, the barrel being provided with a slot connecting said side of the passage with the adjacent side of the barrel, a clamp slidably disposed in said slot and having a front end beside said passage and having a rear portion extending part way across said barrel, and a wedge slidably mounted in the barrel for engaging said rear portion of the clamp, whereby when the wedge is moved across the clamp it will push the clamp forward into said passage to clamp a cable therein against the opposite side of the passage, a side of said passage being provided with a recess extending lengthwise thereof through the block to permit water to escape from the passage when said clamp is pushed into it.

5. A cable gripper in accordance with claim 4 wherein the block is provided with a bleed hole extending laterally from the central portion of said recess through an adjacent side of the block.

6. A cable gripper comprising a block provided with a cable passage therethrough, a clamp supported by said block and movable toward said passage for clamping a cable against the side of the passage, an actuating member supported by the block for moving the clamp, fluid pressure actuated means connected to the block for operating said actuating member, and means for delaying the movement of said actuating member until a predetermined fluid pressure is exerted against said fluid pressure actuated means.

7. A cable gripper comprising a block provided with a cable passage therethrough and with a barrel spaced from one side of the passage, the axes of said passage and barrel lying in substantially parallel planes, the barrel being provided with a slot connecting said side of the passage with the adjacent side of the barrel, a clamp slidably disposed in said slot and having a front end beside said passage and having a rear portion extending part way across said barrel, an actuating member in the barrel for pushing the clamp forward into said passage and maintaining it there to clamp a cable therein against the opposite side of the passage, fluid pressure actuated means connected to the barrel for operating said actuating member, and means for delaying the movement of said actuating member until a predetermined fluid pressure is exerted against said fluid pressure actuated means.

8. A cable gripper comprising a block provided with a cable passage therethrough and with a barrel spaced from one side of the passage, the wall of the barrel being provided with a slot connecting said side of the passage with the barrel, a sleeve connected to one end of the barrel, a thin disc clamped between the inner end of the sleeve and said block, a plunger in the sleeve having one end adjacent the disc, an explosive charge at the opposite end of the plunger, a breech block secured to the outer end of the sleeve, means for exploding said charge to drive the plunger through the disc and into the barrel, and means in the barrel and slot actuated by said plunger for clamping a cable in said passage.

References Cited in the file of this patent UNITED STATES PATENTS 330,103 Flietner Nov. 10, 1885 UNITED STATES PATENT ()FFICE CERTIFICATE OF CORRECTION Patent No. 2,858,908 November 4, 1958 Robert Temple It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 50, claim 1, strike out "adjacent" and insert the same before "side" in line 51; line 66, claim 2, strike out "adjacent" and insert the same before "side" in line 67..

Signed and sealed this 3rd day of March 1959.

SEAL) M ttest:

KARL H. mama ROBERT c. WATSON Attesting Ofiicer Commissioner of Patents