US 1805274 A
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Description (OCR text may contain errors)
y 9 B. H. ANDERSON 1,805,214- 4 BRAKE Filed July 3, 1929 swim doc awn maga- Tatented May 12, 1931 UNITED STATES PATENT OFFICE :r H. ANDERSON, OF DETROIT, MICHIGAN. ASSIGNOR TO GENERAL MOTORS CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF DELAWARE BRAKE Appii cation filed July 3, 1929. Serial No. 375,737.
This invention relates to brakes and particularly to vehicle brakes.
An object of the invention is to provide an improvement in the operating mechanism for the brakes acting to check the rotation of the front and rear wheels. Another object is to provide an automatically variable differentiation between the intensity of the braking forces efiective to check the rotation of the wheels at the front of the vehicle and at the rear. A more specific object is to divide the braking force between the front and rear wheels in proportion to the rate of deceleration of the vehicle. Other objects will be understood from the following description.
In the drawings: Fig. 1 is a view in perspective of a portion of the vehicle chassis having my improved brake-applying means associated therewith. Fig. 2 is a view in side elevation of a part of the brake-operating mechanism.
Fig. 3 is a section on line 3-3 of Fig. 2. Fig. 4 is a diagrammatic View to showthe method of operation.
Referring by reference characters to the drawings, numeral 5 designates the longitudinal frame bars of the vehicle; numeral 7 designates the brake drums. One of these drums is to be used with each of the wheels. Thabrakes within the drums may be of any preferred type andare to be actuated by shafts 9 and 9, these shafts having lever arms 10 and 10 respectively. Shaft 9 and arm 10 are shown associated with the rear brakes and the shaft 9 and the lever 10' are shown associated with the front brakes. A
pedal 11 is pivoted at 13 to any convenient.
The ends of the rock shaft have oppositely directed arms 21 and 21. Each arm 21 is connected by a link 23 to one of the rear brakes. Each arm 21' is connected by a link 23' to one of the front brakes. The rock shaft is rotatably journalled at its ends as at in plates 25. These plates are rigidly. secured to arms 27 swingingly supported by pivots 29 carried by brackets 31 secured to the chassis frame members. It will be seen from the drawings that pivots 30 are positioned below pivots 29. By this construction the rock shaft 19 is given a slight forward or rearward movement as the arm 27 swings on its pivot 29. Should there be more clearance Weights represented by numeral 33 are pivoted to the chassis frame member at 35. The weights are so constructed that the center of gravity is well above the pivot. Links 37 connect the portion ofthe weight below pivot with the extreme lower ends of arms 27.
When the vehicle is at rest or travelling at a uniform rate, the releasing springs associated with the brakes operate to hold the parts in the'position shown on the drawings. Whenthe vehicle is moving forward and is being decelerated, the inertia weight 33 swings clockwise. This causes a clockwise rotatlon of lever 27 and a consequent movement of rock shaft 19 slightly to the rear. This results in' a relieving of the tension in the rear rods 23 and in an added pull on rods 23 extending to the front wheel brakes. The equalized action between the front brakes and the rear brakes is disturbed owing to the movement of rock shaft 19 and the brakesatthe front wheels are now more forcibly applied than the brakes at the rear wheels, the extent of the difference being dependent upon the rate of deceleration. The releasing springs at the brakes are in consequence unequally tensioned and when .the rate of travel is again uniform. they restore the equalizer and the parts connected therewith, including the weight to their initial positions.
It will, of course, be understood that under the influence of acceleration the weight will also tend to swing, but since when the vehicle is being accelerated the brakes are released. the movement of the weight and of shaft 19 even a very light Weight 33 since-itoperates under the influence of inertia with a comparat-ively long lever arm. When, as shown in,
Fig. 4 the weight, under influence of inertia, tendsto move in a horizontal direction, the lever arm, whichis effective to divide'the braking forces and which is representedby L. will be seen to be of considerable length.
It therefore requires but a small weight to produce the necessary movement of rock shaft 19 to produce the differentiation in braking action required. It may also be well to note that when the vehicle is on a hill the action of gravity is a force tending to rotate the inertia weight 33 and therefore disturb the position of shaft 19. This disturbing'influence is however negligible as will be seen from an inspection of Fig. 4. In this figure the line designated as W represents the direction of the pull of gravity and L represents thelever arm through which this force is actuated. It will be seen that this short arm L with the small weight will have but little influence in disturbing the position of rock shaft 19. This figure shows very well, by representing the difference between L and L, that the device is quite effective to control the braking action under the influence of inertia but that the disturb ing influence owing to the inclination of the therear Wheels.
difi'erence should be in proportion to the rate vehicle may be regarded as negligible.
The above arrangement for brake application is believed to be highly desirable. If the weight of .the vehicle be distributed with substantial uniformity among the four wheels,
so that each wheel supports an equal load, the brakes should be applied substantially equally to each wheel and, of course, the braking force at each wheel may be only slightly less than enough to cause wheel locking. When such a vehicle is in motion and the four brakes are applied, the braking force may be considered as acting below the center of, gravity ofthe vehicle in a direction opposite to the direction of travel. I The mass of the vehicle therefore tendsto move forward and as a result the force applied by the vehicle between the front wheelsand the ground becomes greater and that between the rear wheels and the form carries out the inventive idea. It will be understood that in practice the invention maiy be otherwise embodied.
t will also be understood that the accompanying claims are intended to cover the in? vention as broadly as the state of the art permits.
I claim: 1. In brake operating mechanism, front wheel brakes, rear wheel brakes, brake operating means, connections between the brake operating means and brakes including a rock shaft, means to support said rock shaft for movement whereby said rock shaft may function to effect equalization between the front brakes and rear brakes, inertia means, connections from said inertia means to said rock shaft supportin meanswhereby said inertia means may, un er the influence of deceleration, move said rock shaft sup orting means a and thereby move said rock sha t to unbalance equalization and varythe intensity of brake action of the front wheel brakes and rear brakes.
- 2. In brake operating mechanism, front 9 wheel brakes, rear wheel brakes, brake oper ating means, a rock shaft havinv an arm, a link connecting said arm to said brake operating means, arms on said shaft, connections from said arms to said brakes, pivoted swinging supports, said rock shaft being journalled in said supports below the pivots of said sup ports, pivoted weights, connections from said weights to said supports.
In testimony whereof I aifix my signature.
BERNARD H. ANDERSON.
ground becomes less. Since the braking.
be evident that after the first act of braking,
wherein the braking force should be substantially equally distributed, the braking force should: be unequally distributed a greater force being applied to the front wheels than to It will also be clear that the of deceleration. This is precisely what myinvention is designed to accomplish. I have shown one embodiment which in a simple