US2555170A - Internal collapsible chuck - Google Patents

Description

y 1951 J. w. WALL 2,555,170

INTERNAL COLLAPSIBLE cnucx Filed June 6, 1949 s Sheets-Sheet 1 INVENTOR. John W WQ/l 15mm, Hand!) May 29, 1951 J. w. WALL INTERNAL COLLAPSIBLE CHUCK Filed June 6, 1949 3 Sheets-Sheet 2 6 Fey. /2.

INVENTOR. John W 1/l crl/ May 29, 1951 J. w. WALL INTERNAL COLLAPSIBLE 0mm 3 Sheets-Sheet 3 Filed June 6, 1949 INVENTOR. John W M/cfl/ BY Patented May 29, i951 INTERNAL COLLAPSIBLE CHUCK John W. Wall, Royal Oak, Mich.

Application June 6, 1949, Serial No. 97,373

12 Claims.

This invention relates to chucks, particularly chucks for supporting such work as pistons that are to be turned or otherwise worked upon.

It is the object of the present invention to provide a chuck which has the double function I of pulling the work or piston solidly back against the nose of the chuck and at the same time provides expanding jaws or pins for engaging the interior of the work or the skirt of the piston.

The pull back action which pulls the work axially along the chuck is effected by quick acting devices such as swinging dogs, while the expanding action to grip the interior of the work is efiected by a plurality of radially movable pins.

Another feature of a modified form of the invention is an arrangement whereby the pins are pushed out in two or more independent sets so that if the interior of the piston skirt is out of round, the pins can grip the interior of the skirt with substantially the same pressure, regardless at what diameter they encounter the walls of the skirt. If the pins are all thrust out by one cam or member at one thrust and the piston skirt on the interior is out of round, then the piston, when engaged in final position on the chuck, will have the skirt distorted. It can be turned into a true cylinder on the exterior, but after the piston is released and the deforming stress relieved, the piston will spring back to an out of round position on the exterior due to the turning while the piston is under stress and deformation. This is an obviously undesirable condition and I have obviated this by providing an arrangement and devices whereby the pins or grips are thrust out in independent sets and independently actuated.

Referring to the drawings:

Fig. 1 is a side elevation showing my improved chuck fastened to the machine head.

Fig. 2 is a longitudinal section of my chuck.

Figs. 3 and 4 are sections on corresponding section lines of Fig. 2.

Fig. 5 is an enlarged fragmentary section of the chuck adjacent the expanding pins.

Fig. 6 is an exploded perspective of the pull back dogs and the actuating rod.

Fig. '7 is a section on the line ll' of Fig. 2.

Fig. 8 is a section on the line 8-8 of Fig. 2.

Fig. 9 is a longitudinal section of the modified form of the invention involving gripping pins actuated independently in independent sets.

Fig. 10 is a section on the line lll-ll! of Fig. 9.

Fig. 11 is a perspective of the independent actuators for the pin sets.

Fig. 12 is a longitudinal section of still another modified form of the invention involving independently actuated pin sets.

Fig. 13 is a section on the line I3--l3 of Fig. 12.

Fig. 14 is a plan view of one of the pads which is bolted to the body of the chuck.

Referring to Fig. 1, I is the rotating head of the machine to which the collar 2 of the chuck is fastened by screws 3. The chuck is provided with a hydraulic cylinder 4 in which moves a piston 5 which is maintained in fluid type sealing relation to the cylinder by means of the 0 ring 6. Some other form of actuator for moving the piston or head 5 might be used. The outer piston 5 is provided at its inner end with a cylinder or barrel 1 which takes the inner piston or head 8 which is sealed to the cylinder wall by means of the O ring 9. The piston rod can be fluid operated or mechanically operated. The coil spring I0 is put under load when the outer piston moves outwardly and the coil spring H is put under load when the inner piston moves outwardly with respect to the outer piston. These two springs l0 and II return the outer piston and the inner piston respectively to the inner position when the hydraulic pressure is relieved. The outer piston is provided with a neck or outwardly projecting rod l2 which is guided in the shell or bearing I3 and prevented from turning by the key pins I 4 which engage in the keyway Hi. The outer end of this piston rod is provided with four flat inclined surfaces or cams l6 which are adapted to engage the chamfered ends of the gripping pins I! (see Figs. 3 and 4).

A retaining ring I8 is held in a recess under the retaining sleeve H! by screws 20. This ring engages in slots 2! (Fig. 5) of the pins to prevent these pins irom dropping out. The retaining sleeve l9 retains the springs 22 in place, and these engage against the shoulders 23v of the gripping pins to return the pins to the inactive, non-expanding relation when the actuating member is released. Hence the pins will retreat into position so that their ends are substantially flush with the periphery of the ring it when the hydraulic pressure is relieved.

The inner piston 8 has a piston rod 24 guided in the interior machined opening 25 of the neck of the outer piston. The end of this piston rod is provided with an opening 26 in which seats a pin 21 which pivots the nub 28, which oscillates in the slot 29 in the end of the piston rod. The body 30 of the chuck is provided with an end portion 3| of reduced diameter which has a slot 32 therein in which pivots a pair of dogs 33 and 34. These are the pull back dogs and it Will be noted from the showing in Fig. 6 that the upper dog has a single spur 35 which fits in between the pair of spurs 36 of the lower dog. These spurs are the operating portions of the swinging dogs. These dogs have the pick-up jaws which, when they are swung out, catch in the wrist pin openings 16 of the piston and thereby pick up the piston and pull it back in solid engagement with the nose or screw plug 31 of the chuck body. The actuating spurs 35 and 36 are actuated by the swinging nub 28 at the end of the piston rod. The nub 28 continues to deliver the thrust of the rod 24 after oneof the pull back dogs has pulled its side of the piston as far back as it will go while the other side of the piston still needs some pull back to get the piston squarely back against the nose 3! of the chuck. This is important as the inside surfaces of the wrist pin openings may not always be in true alignment with each other so that the dogs will pick up the wrist pins at the same instant. The screw plug 3! forms a backing for the spring 38 which bears against the stud 39 that engages spurs 35 and 36 to turn the jaws back into the openings 32 of the reduced portion of the body of the chuck when the thrust on the inner piston 8 is relieved. The pin 1| (Fig. 2) is a key engaging a groove in the stud 39 to keep the stud from turning.

Referring to Figs. 7 and 8, a locator 40 is provided for properly centering the piston on the chuck. This locator comprises a plate provided with four jaws 4|, one at each corner of the rectangular plate. The locator slides on the reduced body portion 10 of the chuck body. Guide pins 42 project from the body of the chuck to guide the movement of the locator. Coil springs 43 press the locator plate outwardly. The limit of the outward movement is imposed by the collar 44 on the reduced end portion 10 of the chuck body. When the piston is placed on the chuck the jaws of the locator plate, which are slightly tapered, fit into the tapered interior 45 of the piston and thereby center the piston on the chuck. As the pull back dogs pull back the piston against the nose of the chuck the locator plate is slid back to the position shown in Fig. 8, where it is at all times centering the piston on the chuck.

The operation is as follows: Hydraulic or air pressure is turned into the cylinder 4 of the chuck (or a mechanical thrust can be used upon the piston). Inasmuch as the exposed area of the inner piston 8 is much greater than the exposed area of the outer piston 5, the first action is to drive the inner piston outwardly causing the piston rod 24 to thrust on the two pull back dogs and pull the piston back squarely against the nose of the chuck by reason of the swinging nub 28 of the thrust rod being able to deliver the thrust to the other dog after one dog has reached the limit of its movement. Thereupon the fluid pressure on the outer piston together with the thrust communicated to the outer piston by means of the spacing spring I I between the outer and inner pistons, serves to overcome the stress of the return spring I!) and pushes the piston rod or neck, together with its four cam surfaces It against the gripping pins l1 spreading these and causing them to grip the inside of the skirt of the piston. This action is very quick and effective. After work has been finished on the piston and it has been turned or machined as 4 desired, the fluid or mechanical pressure is relieved allowing the springs to return the two pistons, the dogs, and the pins to their positions of retreat. The piston can be removed and replaced by another piston very quickly and the work may go on.

In the form of the invention shown in Figs. 9 to 11, a valuable improvement is provided in dividing the expanding pins into sets which are independently operated. Here only one fluid or mechanically operated piston is provided. This is the piston 46 which is returned, after the pressure is relieved, by the heavy and strong coil spring 41. This piston is directly pinned to the piston rod 24 which operates the dogs in the way already explained. The pins are actuated by two sets of tangs. One set 48 projects from the head or piston 49 that slides in the bearing shell 50. The other set of tangs 5! projects from the head 52 which is guided on the piston rod 24. The spring 53 spaces the piston 46 from the head '52 and spring 54 spaces the head 52 from the head or piston 49. The spring 55 serves to return the piston 49 to its inactive position when thrust on this piston is relieved. The spring 54 serves to return the head 52 to its inactive position and spring 41, as already stated, returns the main piston 46 to its inactive position. The springs are of diminishing strength as one reads from left to right. Spring 41 is the strongest spring, spring 53 the next strongest, spring 54 the third strongest, and spring 55 is the weakest spring. The strength of these springs has to be carefully graduated to secure the best results, but this can be determined only by observance and trial.

The action is as follows: When fluid pressure is turned into the cylinder 4 or thrust is exerted upon this piston, this drives the piston to the right against the strong opposition of the return spring 41. This causes the pull back dogs to throw out into the wrist pin openings of the work and pick up the wrist pins; pulling the piston solidly back against the nose of the chuck. In the meantime the locator 45 has already centered the piston on the chuck. Thereupon the thrust of the piston 46 is communicated to the head 52 by the spring 53. This causes one set of tangs, to wit: the tangs 5|, to travel to the right thrustin out the pins that are operated by this set or tangs. At the same time the thrust of the head 52 is communicated by the spring '54 to the head 48 thrusting the tangs 48 out and causing the companion set of gripping pins to simultaneously thrust out and engage the piston skirt. If the inside of the piston is out of round, one set of pins will grip the piston skirt before the other, and the thrust then coming from the main piston will be delivered mainly to the other set of tangs and gripping pins.

With the arrangement shown in Fig. 2 all the thrust is delivered at one time to all the pins and there is no chance for a yield. The pins all go out at an equal distance. The result is that if the inside of the piston is out of round the piston skirt itself is distorted where the one or more pins first meet solid resistance. Consequently. when the piston is rough machined, the periphery will be accurately round while the work is on the chuck, but when the pressure is relieved the dis torted portion or portions of the piston will return to the original positions and the piston will be somewhat out of round on the outside. This may be within the tolerance allowed or may be removed by the finish grinding.

The m dification shown in Figs. 12 to 14 is a" compromise between the form of chuck shown 'in Fig. 1 and the form shown in Fig. 9. Here I use two sets of tangs, one set 55 and the other '51. The set 5? is connected with the 'inner head 58 and the set 56 is connected with the outer head 59-. This outer head 59 is a piston which is guided in the cylinder 4. A third piston or sliding head 60 is provided which has a piston rod 6| which operates the pull back dogs in the same way as in the other two forms of the invention. Spring 62 separates the piston 6!! from the outer head 58. 63 is a vent hole for the air caught between the two pistons.

The gripping pins in the form of the invention shown in Figs. 9 and 12 are assembled into the body of the chuck together with the return spring 65 by means of the ring 55 which is, preferably, in order to facilitate assembly, in the form of four separate pads til (see Figs. 13 and 1e) secured to the flat sides of the reduced neck portion of the body of the chuck by means of screws 68.

The operation of the third form of the invention is as follows: When fluid pressure is turned into the cylinder 4, this is effected first on the piston 68 which has the greater exposed area to drive the piston rod 6! out and cause the pull back dogs to come into operation. Then the fluid pressure on piston 53 and also the thrust on spring 62, drive the tangs 5'5 out and at the same time the thrust through spring 64 drives the head '59 outwardly carrying with it the tangs 56 to drive the other set of gripping pins out. If one set of gripping pins meets resistance before the other, then the thrust can be delivered to the other set of gripping pins by reason of this dividing the gripping pins into several sets and delive ing the thrust to each through the fluid pressure on one piston and the spring connection between this piston and the other piston. It will be understood that there may be other ways of delivering the thrust to pistons 60 and 58 than by fluid pressure, so I do not want to be limited to a fluid operated motor means.

While it is old in chucks to provide the one or more sets of expanding pins to grip the inside of the skirt of the piston, so far as I am advised,

it is new to provide a combination of pull back devices and expanding gripping pins so coordinated and timed that the piston can be pulled back to the same position on the chuck each time, then tightly gripped in this pulled back position. This is very essential because if a full pull back is not achieved each time a piston is set in the chuck, then the tools working on the piston head will cut a different wall thickness in the top of the piston on different pistons. These piston castings are rough and the pull back devices heretofore proposed simply pull the rough piston back against tapered seats that fit inside of the skirt of the piston. It will be obvious that the pull back of the piston will not be the same with each casing, as in some of the pistons the rough inner skirt may fit tightly on the tapered seat before the piston has been pulled back to properly locate the top with respect to the cutting tool used on the top. With my arrangement of pulling the piston back free from the gripping members and solidly against the nose of the chuck and then expanding the skirt gripping members after the full pull back, the piston is always pulled back on the chuck exactly the same distance and consequently there cannot be any substantial variance in the cut of the head of the piston.

.I claim:

1. A chuck for supporting a piston or other work, having in combination a body which can be secured to a rotating head having thrust means therein, sliding means guided in the body of the chuck on which said thrust means operate, expanding gripping members guided in said body for radial movement, pull back members secured on the body for engaging a portion of the piston or other work to be held by the chuck, and connecting means between the said sliding means and the expanding members and the pull back members for causing the pull back members to act on the piston undergoing working to pull the piston solidly back against the chuck body and. then expand the gripping members to grip the piston in this pulled back position.

2. The combination claimed in claim 1 in which the expanding members are pins and the sliding means has extended portions adapted to engage the inner ends of the pins to expand the pins outwardly.

3. The combination claimed in claim 1 in which the expanding members are shouldered pins, springs to return the pins into the body of the chuck, and a ring for retaining the pins and springs in the body, and tapered surfaces on the end of a rod portion of the sliding means serving to expand the pins to grip the work when the thrust means on the head is actuated.

4. The combination claimed in claim 1 in which the pull back members comprise a plurality of swinging dogs with spurs that are normally spring pressed to positions of retreat within the body of the chuck but which can be pushed out when the sliding thrust means is operated, and a rod connected with the sliding means that has a nub that engages the spurs on the dogs to expand them into the wrist pin openings of the piston.

5. A chuck for supporting a piston or other work, comprising a body arranged to provide a support for the work and having a pair of pivoted pull back dogs having overlapping spurs and pivotally supported in a slot in the body of the chuck and a slidable rod guided in the body having on its end a pivoted nub for engaging the overlapping spurs projecting from the dogs, the pivoted nub serving to deliver the thrust of the rod to the engaging jaw of one dog after the jaw of the other dog has been stopped by meeting non-overcomable resistance.

6. The combination claimed in claim 5 provided with a spring pressed stud slidably supported in the nose of the body of the chuck for engaging the spurs 0f the dogs to cause the jaws of the dogs to retreat into the body of the chuck when the slidable rod and the pivoted nub are drawn back.

'7. A chuck for supporting a piston or other work, having in combination a body provided with a, collar for holding to the head of the machine, independent sets of radially expanding and retreating pins slidably supported in the body of the chuck, and means for separately expanding each set of pins independently of the expansion of the other set of pins so that one set of pins may be continued to expand after the other set have met arresting resistance.

8. The combination claimed in claim 7 in which the said actuating means comprises a head slidably supported in the body and a set of tangs to expand one set of pins, a second head and a set of tangs to expand the other set of pins, one of the heads being thrust out by thrust means and the other head being guided in the body of auamvo the chuck and receiving its actuation from the spring thrust delivered from the first mentioned head through means of a coil spacing spring.

9. The combination claimed in claim 7 in which the said means for independently expanding the pins comprises a head slidably supported in the body, and a set of tangs to expand one set of pins, and a second head, and a set of tangs to expand the other set of pins, one of the heads being the piston of a motor and the other head being guided in the body of the chuck and receiving its actuation from the spring thrust delivered from the motor piston to the other head through means of a coil spacing spring, and spring means for returning both the sliding head and the reciprocating piston to their inactive positions after the pressure has been withdrawn from the motor piston.

10. A chuck for supporting a piston on a machine head, having in combination a, slotted body which can be removably secured to said head, dogs pivoted to said body in said slots, spring pressed means which normally swings said dogs to a position of retreat in said body, a longitudinally reciprocating member having a nub adapted to contact the dogs to swing them out into the wrist pin opening in said piston to pull the piston back against the end of the chuck body, radially movable pins supported in said body, springs for normally keeping said pins in a position of re- 30 2,46 ,465

treat in said body, means longitudinally guided in sliding movement about the said longitudinally reciprocating member, said means having cam surfaces arranged to project the pins outwardly when the means is thrust outwardly' 11. The combination claimed in claim 10 in which the longitudinally reciprocating member is timed to first contact the dogs to pull the piston back against the chuck body and then the longitudinally sliding means project the pins out to grip the piston in pulled back position.

12. The combination claimed in claim 10 in which the longitudinally sliding means comprises a pair of separate sliding heads and projecting tangs spring separated and adapted to independently project separate sets of pins outwardly when thrust is applied to the inner head and its tangs and through the spring separating the two heads the thrust is applied to the outer head and its projecting tangs.

JOHN W. WALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,947,957 Tillman Feb. 20, 1934 2,050,828 Buell Aug. 11, 1936 Casella Feb. 22, 1949

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