US2596544A

US2596544A - Band brake

Info

Publication number: US2596544A
Application number: US133639A
Authority: US
Inventors: Reynold F Gamundi
Original assignee: Eaton Manufacturing Co
Current assignee: Eaton Corp
Priority date: 1949-12-17
Filing date: 1949-12-17
Publication date: 1952-05-13
Anticipated expiration: 1969-05-13

Description

May 13, 1952 R. F. GAMUNDI BAND BRAKE Filed D90. 17, 1949 Patented May 13, 1952 BAND BRAKE Reynold F. Gamundi, Mayfield Heghts, Ohio, assignor to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application December 17, 1949, Serial No. 133,639

4 Claims. 1

This invention relates to band brakes and more particularly to two-way band brakes primarily, though not exclusively, useful for braking and locking rotary drums in automatic transmissions or the like.

The object of the invention is the provision of an improved two-way band brake which is adapted for braking in either direction of rotation, wherein substantially the entire effective length of `the brake band is available for braking in either direction of rotation. In general, this is accomplished by providing a magnetic brake drum and a band coiled around the drum with electromagnetic shoes attached to the band at the ends of the band. The shoes are adapted magnetically to cling to the drum upon being energized. An anchor pin is fixed with respect to the drum extending longitudinally and outward of the periphery of the drum. The shoes have ears extending radially outward on opposite sides of the pin, the ears being spaced apart a distance greater than the width of the pin. With this arrangement, the entire length of the band between shoes is effective for braking in one direction or another of rotation simply by causing the shoes to cling to the drum, as will be made clear. Other features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which one of various possible embodiments of the invention is illustrated,

Fig. 1 is a diagrammatic View illustrating the basic principles of the invention;

Fig. 2 is a side -elvation of a brake embodying the invention, with parts broken away and shown in section; and,

Fig. 3 is a transverse section taken on line 3-3 of Fig. 2, with parts broken away and shown in section.

Similar reference characters indicate corresponding parts throughout the several views of the drawing.

Fig. 1 diagrammatically illustrates the basic principle of the operation of the invention. A rotary drum member is shown at A and a band anchoring Vmember at B. These are relatively rotary. Usually, the drum member is rotary and the band anchoring member stationary. A friction strap or band C is loosely coiled around the drum and has both its ends anchored (with play) to the anchoring member at D. At E are shown two shoes attached to the band at spaced points along its length. Means is provided whereby the shoes may be caused to cling to the drum. For example, the drum may be made of magnetic material and each shoe an electromagnet adapted magnetically to cling to the drum upon being energized or excited. With this arrangement, assuming the drum to be rotary and the band anchoring member stationary, the entire portion of the length of the band between the two shoes is effective for braking upon rotation of the driun in either direction.

Referring now to Figs. 2 and 3 of the drawing, which illustrate a practical embodiment of the invention, there is shown at I a casing constituting a brake housing. Rotary in the housing is a brake drum 3, which is made of magnetic material such as iron or soft steel, and which has a cylindric periphery. The drum is shown as fixed on a shaft 5 `iournalled in bearings (not illustrated) in the end walls of the housing I A lined flexible brake band 1 is helically coiled around the drum. An electromagnetic shoe 9 is attached at l to one end of the band. A second electromagnetic shoe |3 is attached at IE to the other end of the band. The band is coiled in counterclockwise direction from shoe |3 to shoe 9 as Viewed in Fig. 3.

Each of the shoes 9 and 13 is also composed of magnetic material such as iron or soft steel, formed to fit against the periphery of the drum and to contain a magnetizing coil I'l. As shown, each shoe has an outer wall |9 with its outside face 2| curved on an arc centered in the axis of the drum, and side walls 23 and a central wall 25 extending from the outer wall toward the drum with their inner edges curved as indicated at 21 to fit against the periphery of the drum. The central wall 25 forms a pole around which is fitted the coil I'l. The side walls project somewhat outward of the outer wall |9 and their outer edges are curved, as indicated at 29, on an arc centered in the axis of the drum.

At 3| is shown an anchoring member which consists of a pin extending longitudinally of the housing and located outward of the periphery of the drum. The pin is fixed in a pair of longitudinally spaced bosses 33 formed on the interior of the peripheral wall of the housing. The shoes 9 and 13 are located between the pin and the L drum and are spaced apart longitudinally with 4` respect to the housing. The pin extends between radially outwardly extending ears 35 and 31 on shoe 9 and between radially outwardly extending ears 39 and 4| on shoe |3. Ears and 31 on shoe 9 are spaced apart on the arc of the outer face of the shoe a distance greater than the diameter of pin 3| so that the shoe 9 is adapted for movement in an arc around the axis of the drum as limited by the engagement of the ears with the pin. Similarly, ears 39 and 4| on the shoe |3 are spaced apart on the arc of the outer face of the shoe a distance greater than the i diameter'of pin 3| so that the shoe |3 is also adapted for movement in an arc around the axis of the drum, as limited by the engagement of the ears with the pin. The ears on the shoes are formed as integral extensions of the side walls of the shoes. The ears 35 on the shoe-9 and the ears 39 on the shoe |3 are the end ears of the shoe and brake band assembly.

The brake band 1 is of such length that, with the band loosely coiled around the drum, ears 35 on shoe Bengage the pin 3| and ears 39 on shoe |3 engage the pin, as .shown in Fig; 3. Thus, while shoe 9 is anchored against clockwise movement as viewed in Fig. 3 and anehors the respective end of the lband against clockwise movement as viewed in Fig. 3, it may move counterclock- Wise within the limit'imposed by ears 31, and while shoe |3 is anchored against counterclock- Wise movement by the ears v39 and ianchors the respective end of the vband against counterclock- Wise movement, it may move clockwise within the limit imposed by ears 4|. i

The shoes are lightly biased against the periphery' of the drum by spring-loaded rollers 43 which bear against the outside arcuate faces 2| of the outer walls |9 of the shoes. Rollers 43 are mounted on shafts 45 supported in bearing members 41 on studs 49. Studs 49 slide in radial sockets 5|V formed on the interior of the' wall of the housing and are biased radially inward by compression springs 53 in the sockets, the latter reacting from the bases of the sockets against the ends of the studs. V i

The magnetizing coils |'l of the shoes 9 and |3 are adapted to be energized or excited through suitable leads (not shown). Normally, both'coils are deenergized and the drum rotates freely within the brake band 1, the band being loose and shoes 9 and |3 voffering no substantial impedance to rotation. Assuming that the drum is rotating counterclockwise as viewed in Fig. 3, and it is desired to-stop it, both coils |`l are en- .ergized The shoe 9 .thereupon 'magnetically clings to the drum and is :carriedaaround with the drum Vcounterclockwise :as' indicated Vby the arrow F in Fig. 3, thereby initiating tightening of -the brake band.

This action is permitted byithe play in the connection ofV the shoe 9`to the anchor pin 3|, and is followed by a frictional servo action occasioned' by the'friction between the brake Vband and the drum which causes the brake 'band tightly to grip and lock the drum against rotation. The final looking action of theband isnot dependent upon themagnetic clinging of the shoe 9 to the drum, this magnetic clinging only initiating the tightening of the band. While,'as above described, the coil |1 for shoe |3V is'here energized, thisv is of only minor effect in braking.

' If 'desired, to stop counterclockwise rotation of the drum, only the coil for shoe 9 need be energized. When the shoes .are deenergized, .the

brake'bandis released.

Assuming` that the drum is, rotating clockwise both coils are energized. The shoe |3 thereupon magnetically clings to the drum and is carried around with the drum clockwise, as indicated by the arrow G in Fig. 3, thereby initiating tightening of the brake band. This action is permitted by the play in the connection of the shoe |3 to the pin 3|, and is followed by a frictional servo action occasioned by the fric'tion between the brake band and the drum which causes the brake band tightly to grip and lock the drum against rotation. The final looking action of the band is not dependent upon the magnetic clinging of the shoe |3 to the drum, this magnetic clinging only initiating the tightening of the band. As before, While coil for the shoe 9 is here energized, this is of only minor effect in braking. If desired, to stop clockwise rotation of the drum, only the coil for shoe |3 need be energized. When the shoes are deenergized, the brake band is released.

Thus, Vthe above-described arrangement is adapted to brake the drum in either direction of rotation. An important feature of the construction is that the same entire effective length of the z brake band is effective for, braking in either direction.

`While in the above-described embodiment of the invention, the'brake drum 3 is rotary and the brake band anchoring member is stationary, it will be understood that this relationship may be reversed. That is, the brake drum may be stationary and the brake band anchor rotary. Moreover. it is also contemplated that the invention may be applied in a system Wherein both the drum and the brake band anchor rotate, in which event, when the electromagnetic shoes` are energized, the drum and brake band .anchor will be clutched together and brought to the same speed. In this event, the device might becalled a clutch,

and the term "brake" is to be understood to refer to such a system, because the action is in fact a braking action wherein one element. is brought .to `a relatively stationary relationship Vwith respect to the other when the brake is set.

'In view of the above, it Will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many `changes .could be made in the above constructions without departing from the scope of the invention, it is intended that all matter vcontained in the above description or shown in the accompanyingfdrawing shall' be interpreted 'as illustrative'and not in a limiting Sense.

I claim:

' 1. A- brakecomprising a housing, a magnetic brake drum rotary in the housing, an anchor pin fixed in the housing extending longitudinally and located outward of the periphery of the drum, a lined brake band coiled around the drum, and electromagnetic shoes attached to the band at its ends and 'located'between the pin and the drum,

' the shoes being adapted magnetically .to cling to the' drum upon being energized, each shoe having .ears extending radially outward therefrom'on opposite sides of the pin, the ears being spaced apart a distance greater than the width of the pin.

2. AV brake comprising a 'housing, Va magnetic brake drum rotary in the housing, an anchor pin fixed in the housingiextending longitudinally and located outward of the periphery of the drum, a lined brake band coiled around the drum, and

electromagnetic shoes attached to theband'at its I ends'jandV located. Vbetween the pin Vand the drum. ;the shoes being adapted magnetically to ,cling to ffhedrum. uponb'eing energized, each shoe having an inner curved face adapted to fit against the periphery of the drum and an outer face curved on an arc centered in the axis of the drum and ears extending radially outward therefrom on opposite sdes of the pin, the ears being spaced apart a distance greater than the width of the pm.

3. A brake comprising a housing, a magnetic brake drum rotary in the housing, an anchor pin fixed in the housing extending longitudinally and located outward of the periphery of the drum, a lined brake band coiled around the drum, and electromagnetic shoes attached to the band at its ends and located between the pin and the drum, the shoes being adapted magnetically to cling to the drum upon being energized, each shoe having an inner curved face adapted to fit against the periphery of the drum and an outer face curved on an are centered in the axis of the drum and ears extending radially outward therefrom on opposite sides of the pin, the ears being spaced apart a distance greater than the width of the pin, and spring-loaded rollers biasing the shoes toward the drum.

4. A brake comprising a, rotary magnetic brake REYNOLD F. GAMUNDI.

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

UNITED STATES PATENTS Number Name Date 1,447,837 Normanville Mar. 6, 1923 FOREIGN PATENTS Number Country Date 25,283 Great Britain 1905`