US2814859A

US2814859A - Apparatus for assembling open-ended spring retaining rings on grooved shafts, pins and the like

Info

Publication number: US2814859A
Application number: US584229A
Authority: US
Inventors: Erdmann Hans
Original assignee: Waldes Kohinoor Inc
Current assignee: Waldes Kohinoor Inc
Priority date: 1956-05-11
Filing date: 1956-05-11
Publication date: 1957-12-03
Anticipated expiration: 1974-12-03

Description

1957 H. ERDMANN 9 APPARATUS FOR ASSEMBLING OPEN-ENDED SPRING RETAINING RINGS ON GROOVED SHAFTS, PINS AND THE LIKE Filed May 11, 1956 5 Sheets-Sheet 2 INVENTOR -JHANS [ROMAN/V ATTORNEY 1957 H. ERDMANN 2,814,859

APPARATUS FOR ASSEMBLING OPEN-ENDED SPRING RETAINING RINGS ON GROOVED SHAFTS, PINS AND THE. LIKE v 5 Sheets-Sheet 3 Filed May 11, 1956 Compressed HANS ERDMA NN ATTORNEY APPARATUS FOR ASSEMBLING OPEN-ENDED SPRING RETAINING RINGS ON GROOVED SHAFTS, PINS AND THE LIKE Hans Erdmann, Maplewood, N. J., assignor to Waldes Kohinoor, Inc., Long Island City, N. Y., a corporation of New York Application May 11, 1956, Serial No. 584,229

Claims. (Cl. 29-229 This invention relates to improvements in apparatus for assembling open-ended spring retaining rings on grooved shafts, pins or the like, of the type disclosed in my prior application Serial No. 516,073, filed June 17, 1955, and is more particularly directed to an improved version of such apparatus designed to correct shortcomings which become apparent in the continuing use thereof.

For example, the so-called floating mandrel of the prior apparatus, to which the rings to be assembled are fed one at a time and thence pushed axially therealong by the reciprocating tubular or sleeve-form plunger which telescopes over the mandrel, would sometimes become caught or lodged in the bore of said plunger and raised upwardly by the latter in its return (upward) movement to a position making feed movement of the next ring to be assembled a physical impossibility. It is an important object of the present invention to provide, in automatic ring assembly apparatus of the haracter under consideration, a means which is so constructed and arranged in relation to the mandrel as positively to preclude said mandrel being caught and held in the reciprocating tubular plunger and raised by the latter on its return stroke. More particularly, the invention contemplates and provides mandrel stop means cooperatively related to said mandrel in such a way as to permit the mandrel to lower against the work-piece and thereupon to return to its normal position in which it floats, i. e. is held by a pair of diametrically opposed, swinging clamp jaws in a raised position intermediate the plunger and work-piece as in the prior apparatus, but which positively secures the mandrel against unintentional upward movement with the plunger as the latter partakes of its return stroke. Still another object of the invention is the provision of mandrel stop means functioning to prevent unintentional movement which additionally combines with the aforesaid mandrel holding or clamping jaws of the mandrel above its normal or floating position aforesaid in preventing turning of the mandrel under the radially asymmetrical forces likely to be applied thereto upon the clamp jaws and/or said mandrel stop means moving over the usually eccentric or tapered outer edge of the ring consequent to the latter being pushed axially along the mandrel in the course of an assembly operation.

Another drawback of the prior apparatus resides in its ineffectiveness in assembling the very small-size rings; that is to say, rings whose maximum external diameter is less than the diameter of the bore of the aforesaid tubular plunger, as results in the plunger, instead of abutting on and thereupon pushing the ring axially along the mandrel, simply moving over the same without imparting any movement thereto. Accordingly, another important object of the present invention is to insure against such a fruitless operation through the provision of a tubular plunger constructed and arranged so that its lower edge portion which abuts the ring has diameter rendering it capable of effectively abutting any size of ring capable 2,814,859 Patented Dec. 3, 1957 of being received on the mandrel. More particularly, an object of the invention is to so construct the plunger that its lower tubular end has diameter closely approaching that of the body portion of the mandrel, but is expansible 'so that it may enlarge to a diameter at least equaling that of the maximum diameter of said mandrel and the corresponding diameter of the work-piece. A more particular object of the invention is the provision of a tubular or sleeve-form plunger as aforesaid which is adapted to make abutting engagement with the smallest size retaining ring which the mandrel is capable of handling, characterized in that its lower end portion has the form of an inverted truncated cone whose smaller (lower) end is radially expansible to an internal diameter substantially equaling the maximum diameter of the mandrel and the corresponding diameter of the workpiece.

Yet another object of the invention is the provision of a means for controlling the operation of the air cylinder by which the tubular or sleeve-form plunger is motivated, responsively to the work-piece on which ring assembly is to be efiected being moved to a position directly beneath the mandrel. More specifically, an object of the invention is the provision of control means for said air cylinder which is energized by movement of a work-carrying slide, either by hand or by means of a foot pedal, to a position in which it exactly aligns the Work-piece with the mandrel, and which in turn operates to direct pressure air to the end of the air cylinder as results in the plunger partaking of its working stroke, whereby the apparatus is automatically placed in operation upon the work-piece being correctly positioned with respect to the mandrel.

The above and other objects and advantages of the improved apparatus for assembling open-ended retaining rings on grooved shafts or the like according to the present invention will appear from the following detailed description thereof, taken with the accompanying drawings, in which:

Fig. 1 is a front elevation, partially in section, of the improved apparatus for assembling open-ended retaining rings on shafts and the like as herein proposed, the parts being shown in the respective positions which they assume at the end of each ring-applying operation;

Fig. 2 is a partial View of the apparatus illustrated in Fig. l, which illustrates the additional holding action of the mandrel stop means of the invention on the mandrel upon opening of the mandrel clamp means;

Fig. 3 is a view similar to Fig. 2 but illustrating the mandrel stop means in full open or retracted position to which it is actuable by a retaining ring being moved axially along the mandrel;

Fig. 4 is a View similar to Figs. 2 and 3 but illustrating the full lowered position of the mandrel, and the corresponding position of the related parts at the end of an assembly operation; and

Fig. 5 is a front-to-rear section taken generally on the vertical center line of the apparatus shown in Fig. l, which diagrammatically illustrates the air-cylinder control means.

Apparatus according to the present invention is generally similar in type to that disclosed in my prior application Serial No. 516,073 aforesaid, in that it comprises a horizontal base 10 which mounts an upright standard 11 and a ring hopper 12, to which latter vibratory motion is imparted by means Well known in the art. The base 10 mounts work-piece holding means, to be later described in detail, including a fixture block 13 having an upwardly opening recess or socket formed therein for the reception of a grooved shaft or similar machinepart carrying member 15, in whose groove 16 an openended or split retaining ring from the ring hopper 12 is 3 to be assembled so as to provide an artificial shaft shoulder for securing a machine part such as a plate 17 mounted on the shaft against movement in one axial direction.

A stud-like mandrel 18 is normally suspended above and in spaced vertical alignment with the aforesaid shaft upon the latter being finally positioned, as will be explained. Illustratively, said mandrel has a pointed upper end 18a for receiving or spearing the retaining rings to be assembled as they drop thereonto from above, a cylindrical body portion 1811 having diameter substantially equaling that of the internal diameter of said rings, and a frusto-conical lower end portion 180 whose larger end is disposed downwardly and hence towards the shaft 15, and has diameter corresponding to the diameter of the shaft end 15a over which the ring moves to the plane of the shaft groove 16. Although. diifering in detail therefrom, the preferred means for suspending or floating the mandrel above the shaft corresponds generally to that disclosed in my aforesaid application and comprises a pair of oppositely acting

swingable clamp jaws

19, 20 which are normally maintained in their horizontal or mandrel-clamping position as by means of

coil springs

21, 22, which latter are aifixed at their outer ends to the standard 11 as by screws 23, 23a, the spring inner ends being passed through openings 24, 24a in the upwardly offset, free ends of said

jaws

19, 20. The inneror gripping-end edges of the jaws are substantially vertically disposed and they normally enter diametrically opposed, longitudinal slots 25a, 26a machined or otherwise formed in the periphery of the body portion 18b of the mandrel, the grooves extending substantially for the length of said body portion and terminating at their ends in right-angled shoulders, as best seen in Fig. l. The aforesaid mounting of the

jaws

19, 20 is such that they are adapted to swing downwardly or in descending arcs about the axes of their

mounting pivots

27, 28 in response to downward force applied to the upper horizontal edges of their inner ends and, when such occurs, the mandrel is released and is free to lower on to the shaft 15.

Reference numeral 30 designates an air cylinder which is affixed to the standard 11 above and in axial alignment with the mandrel 18. Connected to the piston 32 of the air cylinder is a tubular or sleeve-form plunger 34 whose bore throughout its major length portion is slightly larger than the diameter of the body portion 18b of the mandrel, whereby the plunger may telescope said mandrel. Preferably, the lower end portion of the mandrel is provided with right-angularly related pairs of

diametrical slots

36, 36a and 36b, 360, of which at least the slots 36, 36a have width as to comfortably receive the aforesaid

mandrel clamping jaws

19, 26, as is necessary to enable the plunger 34 to telescope over the mandrel (see Figs. 3 and 4). It is also to be noted that the tubular mandrel 34 is provided at its lower end with a counterbore 37 of normal or basic diameter corresponding to that of the enlarged end 18c of the mandrel and upper end 1511 of the work-piece.

The retaining rings to be assembled are fed from the aforesaid hopper 12 on to a chute 38 extending downwardly at an inclination from said hopper to a level above the mandrel 18, at which the chute is provided with an opening 39 of diameter enabling the plunger 34 to lower through the chute. The chute inclination is such that the rings (generally designated 40) moving on to the upper end thereof tend to slide downwardly therealong by gravity, finally to drop through the opening 39 on to the mandrel 18 when free to partake of this movement. To provide for orderly one-at-a-time feed of the rings to the mandrel, ring-stop-and-feed means are provided, such illustratively comprising a lever 41 disposed above the chute 38 and being pivoted intermediate its ends to the upright 11, as by a pin or pivot 42, for limited rocking movement. A spring 43 operative between one (the upper) end of the lever and the standard 11 normally biases said lever in counterclockwise direction to a position in which a stop pin 44 depending from the under face of said lever end is lifted from an opening 45 provided therefor in the chute, in which position of the lever a depending pin 46 on its other (lower) end is lowered into a second lower-level opening 47 in the chute, generally as shown. To provide for rocking movement of the lever 41 against the bias of the aforesaid spring 43 a rod 48 is connected to the end of the lever opposite that to which the spring connects, said rod extending upwardly through an offset projection or lug 49 aflixed to the upper end of the plunger 34 and terminating immediately above said projection in an enlarged head 50. The relation of said projection 49 and said head 50 is such that when the plunger 34 is in its full raised position it exerts slight upward pull on the rod 46 as it swings the lever 41 in clockwise direction by an amount sufiicient to raise the pin 46 from its opening 47 and, conversely, to lower the pin 44 into its opening 45. Such results in the lowermost ring 40 of the series thereof disposed on the chute being held by the pin 44 against further movement down the chute. Also, as the pin 46 pulls away from the hole 47, a ring previously held by said pin (as in Figs. 2-4) is free to move downwardly along the chute to the opening 39 and thereupon to drop on to the mandrel 18. Upon the projection 49 lowering from the rod head 50 consequent to the initial movement of the plunger 34 on its downward or working stroke, lever 41 is rocked counterclockwise by the spring 43, such raising pin 44 and lowering pin 46 into its opening 47, thereby to lower the series of rings on the chute a distance of one ring and to hold said ring series until the rod 48 is again raised by the projection 49 upon the plunger returning to substantially its full raised or starting position. Thus it will be seen that the retaining rings to be assembled can only feed one at a time on to the mandrel 18, and that such ring feed is timed to occur upon the plunger having completed or substantially completed its return or upward stroke.

In the operation of apparatus as described above, such of course assuming the parts are in their position shown in Fig. l, and further that a ring to be assembled (designated R) has dropped through opening 39 of the chute 38 to the mandrel 18 consequent to the preceding return stroke of the plunger 32 and is resting on the upper edges of the mandrel clamping jaws 19, 2t), lowering movement of said plunger is of course initiated by supplying air to the upper end of the cylinder 30. Such results in said plunger partaking of its working stroke, during the course of which the lower end of the plunger, consequent to its tubular or sleeve-form construction, moves over the upper pointed end 18a of the mandrel, whereupon its lower edge engages the ring R. Upon such engagement being made, further lowering movement of the plunger effects lowering of the mandrel against the force of the clamping

jaw springs

21, 22 until, finally, the mandrel engages against the upper end of the work-piece (shaft) 15. When this occurs, further lowering of the plunger forces the ring R axially along the cylindrical body portion 18b of the mandrel, the swinging motion permitted the clamping jaws enabling the jaws to recede as the ring moves past same, all as shown in Fig. 2. Further lowering movement of the plunger forces the ring axially over the lower frusto-conical end portion 18c of the mandrel, resulting in the ring being spread to an internal diameter corresponding to that of the work piece 15. Final lowering movement of the plunger moves the ring over the end of the work-piece to the plane of its groove 16, whereupon the ring snaps into said groove (Fig. 4), thus to complete the ring-assembly operation.

Assuming air to be supplied to the opposite end of the air cylinder upon ring assembly having been effected as aforesaid, the plunger 34 begins its upward or return stroke. During the course thereof, the clamp jaws 19,

which have moved back into the slots a, 26a of the mandrel upon the ring having moved downwardly past the same, are free to close on said mandrel and raise it from the work-piece to its floating position illustrated in Fig. 1 which they normally tend to do under the urge of their

springs

21, 22. However, with the prior apparatus as disclosed in my aforesaid application Serial No. 516,073, the mandrel 18 sometimes became caught or lodged within the bore of the lowered plunger 34, with the result that it was raised substantially above its aforesaid normal position, as determined by the action of clamp jaws, by the return movement of the plunger. When such occurred, ring feed to the mandrel became impossible as in such case the upper end of the mandrel projects through the chute opening 39 and blocks passage of the rings therethrough.

According to the present invention, this undesirable feature of the prior apparatus is corrected through the provision of mandrel stop means now to be described. Referring first to Fig. 1, it will be seen that the upright 11 mounts on its front face intermediate the work-piece mounting means 13 and the chuck jaws 19, 20 a pair of

plate brackets

52, 53 which form aligned horizontal slideways in which are received a pair of oppositely disposed

blades

54, 55 which are normally biased to their innermost positions by means of

springs

56, 57 operative between their outer ends and fixed points on the aforesaid brackets. At least the inner (adjacent) edges of said blades are thinned so that they may freely enter the aforesaid oppositely disposed slots 25a, 26a of the mandrel,

and said inner ends are moreover inclined upward1y-outwardly away from their bottom edge lines which lie on a common horizontal line, as indicated at 54a, 550, Fig. 3. As also seen in Fig. 1, said common bottom-edge line of the

blades

54, 55 is spaced from the common upper-edge line of the clamp jaws 19, 20 (upon the latter being in their normal horizontal position) a distance equaling the axial length of the mandrel slots 25a, 26a.

Thus, in the normal or floating position of the mandrel 18, the inner ends of the

mandrel stop blades

54, 55 project into the mandrel slots 25a, 26a and engage along their common bottom edge line against the lower rightangled ends or shoulders of said mandrel slots. Correspondingly, the inner ends of the

clamp jaws

19, 20 also extend into said mandrel slots and bear along their common top edge line against the right-angled, upper end shoulders of said mandrel slots. Hence the aforesaid arrangement of clamp jaws and stop blades is such that said clamp jaws normally secure the mandrel in its normal raised position and said blades positively hold the mandrel against being raised past said normal position, as when it is caught or lodged within the plunger 34 and tends to move upwardly with said plunger.

It will be understood, of course, that consequent to their sliding mounting and the inclination of their upper inner edges 54a, 55a the aforesaid

mandrel stop blades

54, 55 interpose no interference to the lowering movement of the ring R as the plunger 34 telescopes over the mandrel. Instead, as best shown in Fig. 3, the ring merely earns the blades outwardly against the bias of the

springs

56, 57 as it is pushed past same. Upon the ring passing said

blades

54, 55 the latter again close on the mandrel so that they normally assist the

clamp jaws

19, 20 in holding the mandrel against turning. In addition to this normal assist action, said

blades

54, 55 also serve the important function of securing the mandrel against turning movement about its axis, which sometimes occurs consequent to the radially asymmetrical forces likely to be applied thereto by the

opening clamp jaws

19, 20 when a tapered ring is being pushed past said jaws, as in Fig. 2. Thus, the

blades

54, 55 take over the function of the

clamp jaws

19, 20 in holding the mandrel against rotation when said clamp jaws are either unable to act in this capacity or are actually applying forces to the mandrel tending to turn it.

Another objectionable feature of the prior apparatus was found to be present in its inability effectively to assern'ble the very small sizes of rings, i. e. rings having external diameter less than the bore diameter of the lower end of the plunger 34. According to the present invention, however, this objectionable feature is overcome by forming the lower end portion 34a of the plunger 34 to inverted frusto-conical shape, and with a smaller-end diameter which is slightly less than the larger-end diameter of the conical upper portion 18a of the mandrel. Thus, upon the plunger partaking of its working stroke, its lower edge first engages on the conical surface 18a of the mandrel, and, consequent to said edge having smaller internal diameter than that of the conical mandrel portion, the plunger is rendered eifective to act on the smallest size of ring which the mandrel can take, and of course it also exercises a slight gripping action on the mandrel as tends to lift it to its normal raised position.

Since the lower end of the plunger 34 must expand to a diameter as great as that of the lower large-diameter end of the mandrel (and correspondingly of the workpiece) in order for the plunger to move downwardly over said latter parts, as in Fig. 4, it is a further feature of the invention that said inverted frusto-conical end 34a of the plunger is made radially elastic or expansible, preferably both through the provision of the aforesaid diametrically opposed slots 36-36(2, inclusive, which are of course cut through said lower frusto-conical end of the plunger, and also by thinning the walls making up said lower end portion 34a of the plunger, as indicated at 58, 59, compared to the wall proper of the plunger body.

Thus, consequent to the reduced diameter of the lower end edge of the plunger, as compared to that of the bore above said edge, the plunger is capable of engaging with and exerting push on any size of retaining ring which the mandrel can handle, even to the smallest sizes of such ring. At the same time, the lower end of the plunger is suificiently elastic or flexible that it is capable of expanding to a diameter enabling it to telescope over the larger diameter-end of the mandrel and the corresponding diameter of work-piece.

According to a further practical feature of the present apparatus, means are provided for initiating travel of the plunger 32 on its working stroke under control of the workpiece (shaft) 15 being positioned below and in exact alignment with the mandrel 18. For this purpose the fixture block 13 which directly mounts the work-piece is itself a component of a slide assembly 60 which is adapted to slide in a slideway member 61 afiixed to the base 10 with its center line coinciding with the front-to-rear vertical center line of the apparatus. Also disposed on the base 10 and rearwardly of the slideway is a normally open control switch 62 of a type that when engaged by the slideway is adapted to close the circuit of a solenoid 63 whose armature 64 is connected by suitable linkages 65 with the operating lever 66 of a four-way valve 67 in the compressed air line to the air cylinder 30. With the valve 67 in its position illustrated, compressed air is being admitted to the lower end of the air cylinder, thus maintaining the plunger 34 in raised position. However, when the slide assembly 60 is moved inwardly, either by hand or by foot-operated lever means, for example, to a position such that it engages and closes switch 62, pull on the valve-operating lever 66 by the solenoid 63 causes movement of the valve to a second position in which it supplies compressed air to the upper end of the air cylinder 30, resulting in the piston 32 and plunger 34 being actuated throughout its working stroke. Any suitable means for effecting return movement of the valve 67 to its illustrated position upon the ring-assembly operation having been completed may be employed. It will of course be understood that the movement of the slide assembly 60 and/or position of the switch 62 are such that the switch is closed at the instant that the work-piece is positioned inexact vertical alignment with the mandrel 18.

. While the above described apparatus has been found in practice to fulfill the objectives therefor as explained in the foregoing in able and effective manner, it will be understood many changes could be made in carrying out the above constructions without departing from the scope of the invention, and it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. Apparatus for assembling open-ended retaining rings on grooved shafts and the like comprising, in combination, means for supporting a grooved shaft in upright position and with its grooved end disposed upwardly, a ring spreading mandrel disposed above and coaxial with said shaft for receiving a ring to be assembled and for spreading it during its movement therealong to the grooved end of the shaft, a vertically reciprocable tubular plunger normally disposed above and coaxial with the mandrel and adapted during its lowering movement to telescope over the mandrel and shaft end, thereby both to push a ring received on the upper end of the mandrel axially therealong to the groove of said shaft and to spread the ring over said shaft end, said mandrel having diametrically opposed longitudinal slots in its periphery,

the lower ends of which terminate in abrupt shoulders,

releasable mandrel-clamping means for holding said mandrel in a normal position raised from said shaft end and being also effective normally to secure the mandrel against turning movement comprising oppositely acting pivoted arms spring-biased for swinging movement to an active position in which their adjacent inner ends extend into said mandred slots and grippingly engage the mandrel body, said arms being swingable to an inactive position in which their said inner ends are without said slots responsively to said plunger in its lowering movement acting on said arm ends through a ring being pushed along the mandrel, said plunger being provided with diametrically opposed arm-receiving slots which enable said arms to return substantially to their said active position within said mandrel slots upon the ring lowering past said arms, and means normally coacting with said mandrel slots and their lower-end shoulders for preventing upward movement of the mandrel past its normal raised position and being also operative, during the interval that the said inner ends of the mandrelclamping arms are without the mandrel slots as aforesaid, to secure the mandrel against turning movement about its axis under asymmetrical forces applied thereto by the ring being pushed therealong, said last means being retractible from the mandrel slots responsively to engagement therewith of the ring being pushed along said mandrel.

2. Apparatus for assembling open-ended retainingi rings on grooved shafts substantially as setforth in claim working stroke said plunger is enabled to act and exert push on the smallest size'ring receivable by the mandrel and on its return stroke it exercises a gripping action on the mandrel tending to raise it to its normal raised position.

3. Apparatus for assembling open-ended retaining rings on grooved shafts substantially as set forth in claim 1, wherein'said last means comprises oppositely acting blades mounted for sliding'movement toward and away from said mandrel, said blades being spring-biased towards said mandrel to an active position in which their inner ends extend into the mandrel slots and engage against the lower-end slot shoulders thereby to determine the uppermost raised position of the mandrel.

4. Apparatus for assembling open-ended retaining rings on grooved shafts substantially as set forth in claim 1, wherein said plunger is radially expansible and has an effective inner diameter whenunstressed which is slightly less than the diameter of the mandrel body whereby the plunger on its return stroke tends to raise said mandrel, and said last means comprises oppositely acting blades mounted for sliding movement toward and away from said mandrel and being spring-biased to an active position in which their inner ends extend into the mandrel slots and engage against the lower-end slot shoulders thereby to prevent upward movement of the mandrel past its normal raised position as aforesaid. I

5. Apparatus for assembling open-ended retaining rings on grooved shafts substantially as set forth in claim 1, wherein said mandrel slots also terminate at their upper ends in abrupt shoulders, and wherein said last-named means comprises oppositely acting blades mounted for sliding movement toward and away from said mandrel and are spring-biased to a normal position in which their inner ends extend into the mandrel slots, the length of said mandrel slots and the spacing between said pivoted arms and said sliding blades being such that in the normal raised position of the mandrel the upper edges of the pivoted arms abut the upper-end slot shoulders and the lower edges of the blades engage the lowerend slot shoulders.

References Cited in the file of this patent UNITED STATES PATENTS 979,438 Courtney Dec. 27, 1910 2,755,538 Kirsch July 24, 1956 2,773,409 Huyett Dec. 11, 1956 2,775,283 Greer Dec. 25, 1956