US2412048A - Means for grinding small holed bushings - Google Patents

Description

'Dec.3,194. J, KAPLAN 2,412,048

MEANS FOR GRINDING. SMALL-HOLED BUS'HINGS Filed Nov. 24, 1945 INQENTOR Josey/2 [(6 BY 5 a ATTORNEY Patented Dec. 3, 1946 MEANS FOR GRINDING SIHALL HOLED BUSHINGS Joseph Kaplan, Brooklyn, N. Y.

Application November 24, 1945, Serial No. 630,638

3 Claims.

This invention relates to new and useful improvements in a machine for the grinding of small holed bushings or other parts where the outside periphery is to be concentric or in similar relation with the holes.

More specifically, the present invention proposes the construction of a, machine for grinding small parts such as bushings having a center bore of extremely small size, the small size of the bushings making it difiicult if not impossible to handle same in conventional machines.

The new invention has particular application to the art of grinding to size, extremely small bushings concentric with their holes. Using it, an extremely high degree of accuracy will be readily and consistently obtained, even where it is required to prepare very large numbers of small bushings in rapid succession on one and the same machine, utilizing but a minimum amount of time for aligning, precision grinding and ejecting the bushings. It will readily be seen that the new method and machine are extremely efficient in operation, yet eminently simple in design, easy to install, and relatively easy .to operate Without difficulty even by unskilled operators lacking prolonged periods of training and instruction heretofore necessary for efficient operators in this art. Many other advantages of the invention will readily appear to those skilled in the art studying the teachings of the instant specification.

A further object is to provide a machine for grinding small bushings exteriorly concentric with their axial bores, said machine having a stationary wire held taut between two chucks, the wire forming a support for the bushing to be ground.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the appended claims in which the various novel features of the invention are more particularly set forth.

In the accompanying drawing forming a material part of this disclosure- Fig. 1 is a front elevational view showing the machine of the present invention with the bushing to the ground in position for having the method of the present invention performed thereon.

Fig. 2 is a plan view taken from above and showing the embodiment of the invention shown in the preceding figure.

Fig. 3 is a perspective view of a bushing used and prepared in accordance with this invention.

Fig. 4 is a perspective view in detail showing the keyed fitting which holds and causes rotation of the bushing of Fig. 3.

Fig. 5 is an enlarged axial section through the fitting and bushing, which are in mating position.

Fig. 6 is a perspective view of the fitting and the corresponding holding part pictured in detail apart from the remainder of the machine.

The main principle of the present invention consists in having a centrally aligned stretched wire held firmly in between two chucks. The wire acts as a stationary axis over which the bushing to be ground rotates, while it is being ground by a grinding wheel. The diameter of the wire should be preferably about one to several tenthousandths of an inch less in diameter than the bore in the bushing in order to get good results in the concentricity of the inside and outside diameters of the bushing.

The machine, according to this invention, comprises two parallel vertical standards l0 and H holding two stationary chucks l2 and 22 respectively. The construction of the tail stock of a lathe will very well suit the purposes of chuck 22 in adjusting the distance between the two chucks as needed. In the present instance chuck 22 is shown as having a stem 13 sliding in a bore in the standard I I, a set screw 28 being employed for locking the chuck 22 in any adjusted position.

A fitting or auxiliary bushing l1, best shown in Fig. 4, is provided. Its function, as will presently appear, is to drive the bushing 26 (Fig. 3) while it is being ground. The bushing l1 consists of a piece of round stock of steel having a hole l9 drilled through the center and having a tooth extending diametrically across one end. This tooth 20 is adapted to fit loosely in a slot 21 formed in one end of the bushing 26. Bushing 26 has an axial bore 25.

An electric motor 3| drives a pulley l4 mounted on the standard In by mean of a belt. A dog 2| is secured to the pulley and has a collar surrounding the bushing l1 and secured thereto by a set screw 18. The dog has two arms secured in holes in the pulley. Thus rotation of the pulley effects rotation of the dog and consequently rotation of the auxiliary bushing, the auxiliary bushing, when its tongue 20 is disposed in the slot 21 of the bushing to be ground, rotating this bushing.

In order to prepare the bushing 26 for external grinding, the bore 25 must first be made and the slot 21 must be milled therein. After the external surface is ground, the end having the slot 21 may be ground to eliminate this slot.

The machine further comprises'a wire i which is first secured in the chuck I2. The auxiliary bushing I1 is then slid on the wire and into the collar of the dog where it is secured by the set screw l8, the arms of the dog being inserted in the holes in the pulley. Then the bushing 26 to be ground is slid on the wire, the tooth 20 and slot 2'! being adjacent each other and interfitting. The end of the Wire I6 is then gripped in the chuck 22 which is then adjusted longitudinally to give the correct distance between the faces of the two chucks and the adjacent faces of the bushings. This distance is preferably only a few thousandths of an inch, but is shown larger in the drawing for clarity. That is to'say, the

bushings, When interfitted, do not entirely fill the space between the chucks but some clearance is permitted to allow the bushings to rotate unhampered.

A grinding wheel 29, mounted on a shaft .39, is shown fragmentally in Figs. 1 and 2. This wheel is rotated by another motor, in a well known manner, to grind the bushing 26. The wheel 29 will be mounted for longitudinal movement along the bushing 28. As grinding wheels of this type are well known, no further description or showing thereof is deemed necessary.

In order to grind the bush-ing 2B, the motor 3| is started and thus the bushing 26 rotates. At the same time the grinding wheel 29 is started. The wheel 29 is moved back and forth along the bushing 2-6 until the exterior surface of the bushing has been ground the desired amount. After the outside diameter of the bushing is finshed to size, the chuck 22 is opened and the bushing 28 removed and a new one inserted on the wire I'B, whereupon the operation is repeated.

While I haveillustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the precise constructions herein disclosed and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent is:

1. In a machine for grinding a bushing or the like having a central bore, two spaced chucks, a

wire or rod secured at its ends therein, an auxiliary bushing mounted on said wire or rod said bushing to be ground being adapted to be mounted on said wire or rod next to said auxiliary bushing, said auxiliary bushing having means for locking with said bushing for rotating the same when said auxiliary bushing is rotated, and means for rotating said auxiliary bushing.

2. A machine for grinding a bushing or the like having a central bore and a diametral slot in its end comprising two spaced standards, a pulley mounted on one of said standards for rotation, a chuck-secured to said standard, an electric motor for driving said pulley, a chuck ad ustably secured to said other standard, a wire or rod secured at its ends in said chucks, an auxiliary bushing freely supported on said wire or rod, a

dog .secured to said auxiliary bushing and to said pulley for rotating said auxiliary bushing, said auxiliary bushing having a diametral tongue in one of its ends for interfitting with said slot in said bushing to be ground, said bushing to be ground being adapted to be freely supported on said wire or rod, and rotatable grinding means for grinding the exterior surface of said bushing to be ground.

3. A machine for grinding a bushing having an axial bore and a diametrical slot in one end comprising two spaced standards, a chuck rigidly secured to one of said standards, a chuck adjust: .ably secured to the other of said standards, a pulley rotatably mounted on the first of said standards, means for rotating'said pulley, a wire or rod secured at its ends in said chucks, a fitting rotatably mounted on said wire or rod having a diametrical tongue on one end for interfitting with said slot when said bushing is mounted on, said wire or rod, a dog connecting said fitting and pulley for rotation of said bushing, said dog having two legs secured in holes in said pulley and a' collar surrounding said fitting and provided with a set screw for firmly locking said collar and fitting and rotatable grinding means for grinding the exterior surface of said bushing to be ground. V

JOSEPH KAPLAN.

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