US1689274A - Grinding of gear-wheel teeth - Google Patents

Description

GRINDING OF GEAR WHEEL TEETH Filed Dec. `27, 1927 1 IK, "rk r Patented Oct. 30, 1928.

UNITEDY STATES PATENT OFFICE.

HARRY HALES ASBRIDGE, F ASHTON-ON-MERSEY, ENGLAND, ASSIGNOR TO THE CHURCHILL MACHINE TOOL COMPANY LIMITED, 0F BROADHEATI-I, NEAR MAN- CHESTER, ENGLAND.

Application led December 27, 1927, Serial No.

been made to determine the tooth form accurately. In particular I referred to Noyes British patent specification No. 107,608 in which there is described the use of a templet or cam corresponding in shape to one face of the tooth to be produced, this cam being secured to the spindle carrying the wheel to be ground and arranged to bear against a fixed abutment. Motion of the wheel in one direction was obtained by the interaction of the templet and abutment, Whilst in the reverse direction the motion was determined by the action of a spring arranged to hold the templet in Contact with the abutment. I .also referred to a method described in the Lees Bradner Company British patent speciiication No. 195,381. In this specilication there is described a double acting cam fixed on the spindle carrying the wheel to be ground, the cam being located between a pair of fixed abutments so that the cam determines the angular movement ot' the wheel positively in both directions of motion. v

My experience in the construction of gear grinding machines led me to the conclusion that the maximum of advantages was associated with a method involving the use of a single templet or cam in combination with a single fixed abutment, a spring being employed to keep the templet in contact with the cam during the return movement of the wheel. In the form previously employed by Noyes, the mechanism employed for carry@ ing out this method suifered from a serious disadvantage which rendered the method im practicable at high speeds, the disadvantage being due to the fact that large movements had to be imparted to the spring. As described in my previous specification I succeeded in solving the problem of the Noyes method of procedure by the use in conjunc- GRINDING OF GEAR-WHEEL TEETI-I.

242,801, and in Great Britain October 18, 1927.

tion with the spring, of a movable support or carrier, the movements of which were coordinated with those of the slide carrying the toothed wheel to be ground. By such invent tion I was able to employ a single templet and fixed abutment in a machine capable of producing accurate work at a high rate of speed, and machines made in accordance with my previous invention have been put into successful operation. So long as the machines are required only for wheels of comparatively 00 small diameter, no difiiculty is encountered, but for dealing with wheels of comparatively large diameter the invention forming the subject of my previous British patent above mentioned results in a machine which is costly and is undesirably large. I have, therefore, reverted to the problem of the single templet and have devised a new form of spring control which enables the desirable simplicity and compactness to be readily obtained in machines adapted particularly for wheels of relatively large. diameters.

The present invention comprises the employment in combination with a single templet, an abutment for the same, and a spring one end of which acts on the templet, of a cam or reaction member which is acted on by the other end of the spring and is movable rrelatively to the templet, and an abutment with which the reaction member co-operates.

Referring to the accompanying sheet of explanatory drawings Figure l is a side elevation showing diagrammatically one manner of applying the invention to a wheel tooth grinding machine.

Figure 2 is a cross'section on the lines l, 2, Figure I, and Figure 3 is a cross section on the lines 3, 4.

In carrying the invention into effect as shown in the drawings, the spindle a to which is secured the toothed wheelv 2') to be treated is carried upon a slide to which a vertical i reciprocatory motion is imparted in the usual way. The slide is omitted from the drawings to avoid confusion. The toothed'wheel o is 95 acted upon by the Hat face of a grinding wheel, a portion of which is indicated by c. This wheel rotates about a vertical axis.

-When the base circle of the toothed wheel is used as the datum line in the generation of the tooth form, the axis ot the spindle a is reciprocated in a plane at right angles to that of the grinding face of the wheel c, and the elements d, e which will be described hereafter are arranged with their centres on a tangent to the base circle of the toothed wheel. Following the method described in the previously mentioned Noyes Patent, a single templet 'f is secured to the spindle t through the medium of a sleeve Z, and this templet co-operates with the abutment roller e which is mounted in a lixed position on the frame of the machine. It will be understood that the coniiguration of the tooth face is determined by the configuration of the templet f. Y

The templet f is maintained iirmly in contact with the abutment e by means or" a helical spring g contained in a housing 71, pivotally attached to the templet Seeing that a relatively large angular movement is imparted to the templet in each reciprocation of the spindle af, it i'ollows that if the reaction to the spring g were provided by a lixed abutment on the machine framefthe spring would experience correspondingly large movements. For the reason explained in my previous British patent speciiication, such a condition is impracticable when a machine is required to operate at a high rate oi' speed. According to my former invention I solved this dit iculty by arranging the spring in conjunction with a carrier connected to the slide on which the spindle a is mounted.

According to the present invention I arrange alongside the templet f a reaction member having a cam-shaped periphery t' which co-operates with another ixed abutment roller (Z on the machine frame. The periphery of the member z' may be of the same configuration as that of the templet j", but strict accuracy in this respect is unnecessary as any shape which does not involve a large relative movement between the parts z' and is suitable. The cani member e' is connected to the spring g through a plunger and the spring g is put into an initial state of compression in order that it may exert the required pressure on the part During the reciprocation of the spindle 0, both parts z' and f perform an angular movement due to their interaction with the fixed abutments d and e and so impart the required angular movement to the spindle a1. It must be understood, however, that this movement is determined solely by the templet f, the part c' serving merely to maintain an appropriate state ot compression in the spring g. Any diierence between the conigurations of the parts z' and f will result in corresponding relative movements oit' those parts under the action ot the spring, and the latter will experience a corresponding variation of length,

but as this can be made very small it introduces no inconvenience.

It will be apparent from the foregoing that by this invention I am able to avail my self or the advantages ot' the single templet method of procedure and at the same time I am able to maintain in a very simple and eiiective manner a comparatively constant state of compression or tension in the spring.

In the complete machine any convenient provision is made for reciprocating the spindle a and in conjunction with the spindle any convenient indexing mechanism may be em ployed for moving the wheel from one position to the next after each tooth face has been treated. In the example illustrated, the parts z' which are mounted on a sleeve Z are secured to the spindle a through the indexing mechanism. One of the abutments d, e, preferably d, is made adjustable by mounting it upon a screw operated carrier is as shown in Figure l.

The invention is not limited to any particular mechanical details, as these may be varied to meet diliferent requirements. Also the invention is not limited to the example above described. Though preferable, it is not es sential to mount the part z' in immediate conjunction with the part f as these two parts may be separated if desired and connected through a spring and appropriate linkage or other mechanism. TWhilst I have described a machine in which the work spindle reciproca-tes in a vertical plane, it will be obvious that it may be arranged to reciprocate in a horizontal plane, or any other plane, the relative disposition of the grinding wheel axle being correspondingly changed if necessary.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is l. In machines of the type specified for grinding gear wheel teeth, the combination comprising asingle templet arranged in operative connection with the toothed wheel, an abutment with which the templet co-operates, a spring one end of which acts upon the templet, a cam member which is acted on by the other end of the spring and is movable relatively to the templet, and a second abutment with which the cam member co-operates, sub stantially as described.

2. In machines of the type specified for grinding gear wheel teeth, the combination comprising a single templet mounted axially with and secured to the toothed wheel, a

Comprising a templet secured to and mounted coaxially with the toothed Wheel, a cam' thereto, telescopic members in connection with the templet Aand cam member respeetvely,a springlocated between said telescopic members, roller abutments cooperating with the templet and cam member respectively, and means for adjusting one of the rollers, 10 substantially as described.

In testimony whereof I have signed my name to this specification.

' HARRY HALES ASBRIDGE.

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