US1741470A - Starting gate for race courses - Google Patents

Description

Dec. 31, 1929. c. B. MAUCHAN STARTING GATE FOR RAGE COURSES 6 Sheets-Sheet Filed Dec. 11, 1928 m 6 8 9 0 w 9% 1 a l I n n w m a. JLT -L w F a u/W T 1 SJ 2 H 0 Y.J L1? m Y O l 'llllll f F a Q 0 I 9 I 3 5 3 7 H H M 0 9 W 9 9 2 W m 0 Dec. 3; 1929. c, MAUCHAN 1,741,470

STARTING GATE FOR RACE COURSES Filed Decll, 1928 6 Sheets-Sheet 2 Dec. 31, 1929. QB. MAUCHAN STARTING GATE FOR RACE COURSES 6 Sheets-Sheet N... m u m m m m w m 5 8 M m 8 u M m 5 .\r.-. F9 9 fl E 6 0 Q 0 9 .1- aw 1W i i1 2 MW 2 UN m H H L s I 2 m 2 7 QHWMA V m 9 6 3 P. a 3 5 2 a a v /:I H 5 7 V m Q Q i a a a c. B. MAUCHAN 1,741,470

STARTING GATE FOR RACE COURSES Filed Dec. 11, 1928 6 Sheets-Sheet 4 I Dec. 31, 1929.

M u J... 4 a w M M/M/ 55...... o o 0O -00 5 m m 1 w 4 Eu 0 w 9 9 m 4 0 0 5 7 5 n u L 6 3 6 W H Dec. 31, 1 929. c, UC 1,741,470

STARTING GATE FOR RACE COURSES File Dec- 1928 6 Sheets-Sheet 5 58 FIG] Patented Dec. 31, 1929 PATENT OFFICE CHARLES BUGil-FAIL). 1\T MAUCI-IAN, OF GLASGOW, SCOTLAND STARTING GATE FOR RACE COURSES Application filed December 11, 1928, Serial No. 325,169, and in Great Britain November 15,1928.

This invention relates to improvements in starting gates for race courses.

According to the invention each mast of the starting gate includes tape actuating mechanism comprising a motor actuated by gravity to effect vertical rise of a tapecarrying arm or the like, means for winding up said motor to set position, electrically and manually operable means for releasing the motor, and friction braking means adapted automatically to function during the rise of the tape whereby to bring the motor gradually to rest.

In the following description of the invention one mast or post only of the starting gate has been illustrated, and, owing to the inconvenience of the scale, in detached detail views; it being understood that the gate includes two such masts or posts spaced apart 29 one at each side of the race course at the starting point, the tape-holding arms being col? linear and interconnected by a tape or the like extending transversely of the course. In the accompanying drawings which illustrate in fragmentary detail views one mast or post .of a starting gate according to the invention, Fig. 1 is a fragmentary vertical section through the mast casing or housing the tape-actuating mechanism; Fig. 2 is a fragmentary vertical section in the same plane as Fig. 1 showing the top portion of the mast; Figs. 3 and 4 are vertical sections in the same plane at right-angles to Figs. 1 and 2; Fig. 5 is a vertical section drawn to a larger scale showing the tape-actuating mechanism; Fig. 6 is a fragmentary detail view; Figs. 7 and 8 are detail views at right? angles to each other of the motor shaft; Fig. 7 being an axial section and Fig. 8 an outside a View. Figs. 912 are detail views of an element in the mechanism, Fig. 9 being an axial section, Fig. 10 an end elevation, Fig. 11 a section on the line 1111 of Fig. 9 and Fig. F 12 an axial elevation; Figs. 13-17 are detail views of another element in the mechanism Fig. 13 being an axial elevation, Fig, 14 a section on the line 14 '14 of Fig. 15, Fig. 15 an axial section, Fig. 16 a section on the line 16 16 of Fig. 15, and Fig. 17 an end elevation; Figs. 18, 19 and 20 are detail Views of a tape holding arm, Fig. 18 being a side elevation, Fig. 19 a plan and Fig. 20 a section on the line 2020 of Fig. 18; Figs. 21 24 are detail views of the brake mechanism adjusting key; Fig. 25 is a detail View; Figs. 26 and 27 are detail views at right-angles to each other; Figs. 28 and 29 are detail views at right-angles to each other showing the cap which is threaded on the rear end of the actuating shaft.

Each mast shown comprises a vertical lattice structure 1 of which the lower end (not shown) is adapted to be embedded in a suitable foundation beneath the ground level of the race course. T 5 Sustained by each mas-t, at a convenient heightabove the ground level is a casing 2 enclosing tape-actuating mechanism including a sprocket wheel 3 (see particularly Fig. 5) secured to a partially hollow horizontal shaft 4 (Figs. 1, 3, 5, 7 and 8) revolubly mounted in ball bearings 5, 6 of which the bearing 6 at the front end of the shaft is housed in an opening 7 (Fig. 5) presented by a partition 8 integral with the casing 2 and of which the bearing 5 at the rear end of the shaft is housed in an opening 9 presented by a spider member 10 secured to the casing 2.

Axially penetrating and screw-threaded into the front end of the shaft 4 is a pin 1.1 81) having a reduced inner shank 12 traversing a slot 13 formed transversely in the shaft 4 adjacent to one lateral face of the sprocket wheel 3. Formed .on the outer end of the pin 11 is a polygonal portion '14 adapted to be engaged by the polygonally socketed end of a manually operable crank or handle 15 (Fig. 8) whereby the shaft 4 may be rotated manually to bring the mechanism to initial position as hereinafter explained. Anchored to the shank 12 of the pin 11 within the transverse slot 13 is the upper end of a chain 16 (Fig. 1) adapted. when the shaft 4 is rotated manually in one direction, to coil spirally upon itself in scroll fashion between the front face 3 of the sprocket wheel 3 and a disc 17 carried by the shaft 4 and spaced from said face at the remote side of the slot 13; said disc also serving as a protective cover for the ball bearing 6.

The chain 16 is led downwardly between guide pulleys 18 (Figs. 1 and 3) and trained round a pulley 19 mounted on a weight 20 and then led upwardly to an anchorage bolt 21 secured to the base of the casing 2.

The guide pulleys 18 are j ournalled in ball bearings 22 mounted on bolts 23, 24 carried by the casing 2.

The pulley 19 (Figs. 1 and 3) is journalled in ball bearings 25 mounted in a bifurcated bracket 26 having a shank 27 screw-threaded into the upper end of the weight 20 which is guided for vertical movement on spaced vertical bolts 28 positioned one on each side of the weight and secured at their upper ends in the base of the casing 2 and at their lower ends to a horizontal plate member (not shown) fixed to the mast structure. The pulley 19 and bracket 26 are disposed within a recess 19 formed in the top of the weight The bolts 22 are accommodated within recesses 29 formed one in each side of the weight 20, there being formed near the upper and the lower ends of the recesses, in-

tegral with the weight apertured lugs 30 penetrated by said bolts.

When the shaft 4 is rotated by means of the handle 15 the chain 16 is caused, as already explained, spirally to coil upon itself whereby to raise the weight 20 into the position shown in Figs. 1 and 3.

Wrapping the sprocket wheel 3 and a second sprocket wheel 31 journalled near the top of the mast structure 1 is a chain 32 which carries a horizontally disposed tape-holding arm 33 (Figs. 1, 2, 3, 18, 19, 20).

The sprocket wheel 31 is journalled on ball bearings 34 (Figs. 2 and 4) mounted on a horizontal shaft 35 carried by a bracket 36 secured to the mast 1, the bracket having a cowl shaped top 37 serving partially to enclose the sprocket wheel 31.

The lower end of the bracket 36 presents a socketed boss 38 adapted to engage the upper end 39 of a substantially vertical guide rod 40 of circular cross-section located within the mast structure, the lower end of the rod 40 being fixed in a socket 41 (Figs. 1 and 3) formed in the top of the casing 2.

42 denotes an ornamental member fixed to the top of the mast (Figs. 2 and 4).

Formed in the rear hollow end of the shaft 4, adjacent to the rear face 3 of the sprocket wheel 3, are diametrically opposed slots 43 (Figs. 5, 7 and 8) penetrated by a cotter pin 44 which is free to perform limited sliding movements axially of the shaft within the slots.

Loosely mounted upon the shaft 4 adjacent to the rear face 3 of the sprocket wheel 3 is an externally screw-threaded sleeve 45 (Figs. 5, 9, 10, 11 and 12) in the bore of which is formed an annular recess 46 opening into which is a slot 47 formed in the lateral wall of the sleeve. The slot 47 is of the same circumferential width as the slots 43 in the shaft 4, so that, when one or other of the slots 43 is moved into register with the slot 47, the cotter pin 44 may be inserted into position as shown in Fig. 5. The length of the cotter pin 44 is greater than the diameter of the shaft 4 at the slots 43 so as to extend into the annular recess 46 in the sleeve 45. The sleeve 45 is. axially slidable relatively to the shaft 4 and rotatable therewith as will be hereinafter explained. The front peripheral boundary 46 (Figs. 5 and 9) of the annular recess 46 is engaged by the front edge of the cotter pin 44 whereby the front end face 45 of the sleeve 45 is urged against the rear face 3 of the sprocket wheel 3 by means hereinafter described.

The rear end of the sleeve 45 is formed with dog teeth 48 which engage a mating face formed on the adjacent end of a sleeve 49 (Figs. 5, 1217 mounted on the rear end of the shaft 4 and hereinafter referred to.

In screw-threaded engagement with the sleeve 45 is a nut 50 (Fig. 5) to which is secured a substantially circular disc 51 carrying on its front face, i. e. the face adjacent to the rear face 3 of the sprocket wheel 3, an annular member 52 adapted, on forward axial movement of the disc 51, to engage the rear face 3 of the sprocket wheel whereby to function as a friction braking member serving to arrest the rotation of the sprocket wheel.

Formed on the upper side of the disc 51 is a lug 53 (Fig. 5) having an aperture 54 adapted to be engaged by a prong 55 at one end of a swivel-arm 56 (Fig. 25) having at its other end a prong 57 pivoted to a point on the casing 2 conveniently adjacent to the lug 53, said point being so chosen that the axis of the arm 56 lies substantially transversely of the shaft 4.

The swivel-arm 56 prevents rotation of the disc 51 but permits said disc to move axially of the shaft 4, towards or away from the sprocket wheel 3.

It will be observed from Fig. 5 that the rotation of the shaft 4 and therewith the sleeve 45 in one or other direction will cause the disc 51 and therewith the friction brake member 52 to approach or to recede from the rear face 3 of the sprocket wheel.

The rear end of the shaft 4 is reduced in diairieter and is formed with diametrally opposed slots 58 extending axially of the shaft and adapted for penetration by a cotter pin 59 (Fig. 5) the terminal ends of which project beyond the shaft to enter into engagement with one or other of the pairs of diametrally opposed internal splines 60 formed in the core of the sleeve 49 (Figs. 5, 1517) which is mounted on the reduced end of the shaft 4 and penetrates the inner race of the rear ball bearing 5.

The front of the sleeve 49 is formed with dog teeth 61 which are in constant engagement with the teeth 48 on the rear end face of the sleeve 45 as already explained, the arrangement being such that the sleeves 45 and 49 are in constant operative engagement and rotate together with the shaft 4.

In the position shown in Fig. 5 the sleeve 45 is abutting against the rear face 3 of the sprocket wheel, but, as already explained, this sleeve is free to move axially of the shaft 4,

away from the sprocket wheel 8, the interengaging teeth 48, 61 on the mating clutch faces permitting this movement of the sleeve 45 by entering more deeply into mesh.

Housed within the shaft 4 are coaxially dis-- posed helical compression springs 62, 63 (Fig. 5) abutting at their front ends against a cap 64 interposed between the front terminal ends of the springs and the cotter pin 44, said cap having a central protuberance G5 entering the inner spring 63.

At its rear end the outer heavier spring 62 abuts against the front end face 65 of a sleeve 67 (Figs. 5, 26, 27) interposed between. the rear end of the spring and a cap 68 (Figs. 5, 28 and 29) screw-threaded on the rear end of the shaft 4.

The rear end of the inner spring 63 engages a shoulder presented by a pin 69 ac'nn dated within the hollow sleeve 67 and penetrated transversely by the cotter pin 59, said pin 69 having at its front end a projection 70 entering the rear end of said spring.

At its front end the hollow sleeve 6'7 is formed with diametrally opposed slots 71 extending axially of the sleeve whereby to permit insertion of the sleeve into the rear end of the shaft 4 past the cotter pin 59, the side boundaries of the slots engaging the side faces of the cotter pin.

The rear end face of the hollow sleeve 67 (Figs. 5, 26 and 27) is formed with diainetrally opposed protuberances 7 2 adapted to engage diametrally opposed notches 73 formed in side boundary of a central aperture 74 in the end wall of the cap 68 (Figs. 5, 28 and 29) when said cap is screwed home on the rear end of the shaft 4.

Referring to Figs. 5, 13 17, there is formed in the rear end of the sleeve 49 an annular recess 75 adapted to accommodate the cap 68. The rear terminal end of the sleeve is also formed with diametrally opposed notches 76 and is externally screw-threaded at '77 for engagement with a ring 78 (Fig. 5) covering the outer face of the opening 9 and serving to exclude dust from the ball bearing 5 of which the inner race is clamped between said disc and a shoulder 7 9 integral with the sleeve 49.

Formed in the bore of the sleeve 49 between a shoulder 80 (Fig. 15) near the front end thereof and the front peripheral boundary of the internally splined portion 60 is an annular recess 81 the diameter of which is slightly greater than the overall length of the cot ter pin 59 for purposes hereinafter to be explained.

G11 referring to Fig. 5 it will be seen that the sleeve 49 is held axially on the reduced rear end of the shaft 4 by abutt ng shoulders at 82 between the shaft and the sleeve and by abutting shoulders at 88 between the cap and the sleeve.

The inner race of the ball bearing 8 at the front end of the shaft is clamped between the disc 17 and a disc 84 interposed between the race and a flange 11 formed on the pin ll, the disc 84 serving to prevent ingress of dust into the bearing.

Sustained by the partition 8 of the casing 2 and having one limb or pole depe; ding on each side of the shaft 4 is a horseshoe electro-niagnet 85 (Figs. 1 and 3) of which each limb or pole is surrounded by a coil 88.

Co-operating with the pole faces 87 of electro-magnet is an armature constituted by the substantially horizontal arm 88 of a bellc-rank lever fulcrumed at 89. The arm 90 of the lever extends substantially vertically u wards and terminates in a toe 91 (Fig. l) functioning as an interfering pawl cooperating with protuberances 92 formed on t teeth of the sprocket wheel 3 (Figs. 1, 3, 5, 6)

The armature 88 is provided at its free end with a handle 98 which projects exteriorly of the casing 2 at a point convenient for manual operation.

Pivoted at 94 (Fig. 1) beneath the armature 88 is a safety catch constituted by a boss 95 having a radially disposed protuberance 96 adapted to coact with a cam face 97 formed on the lower side of the armature 88. The inner end of the cam face 97 terminates in a notch 98 adapted to be entered by the protuberance 96 when the armature 88 is in lowered position, i. e., when the armature is clear of the pole faces 87, the pawl 91 being in operative position shown in Fig. 1 to prevent rotatien of the sprocket wheel 3.

The boss 95 of the safety catch is provided with a handle 99 which projects from the easing beneath the handle 99.

It will be evident from Fig. 1 that on depression of the handle 99 of the safety catch the protuberance 96 will be caused to vacate the notch 98and to traverse the cam face 97 whereby to raise the armature 88 and to move the pawl 91 into inoperative position clear of the sprocket-wheel protuberances 92.

The functions of the safety catch are thus to effect release of the sprocket wheel by raising the armature 88 and to maintain the armature in inoperative position clear of the sprocket wheel, it being understood that, when the handle 99 is in raised position, the armature is in lowered position with the pawl 91 in locking engagement with the sprocket wheel.

The sprocket wheel 3 is of relatively large diameter so that comparatively few revolutions thereof will sufhce to effect the necessary movement of the tape.

In the elevated position of the weight 20, i. e. the lowered position of the tape arm 33, shown in Figs. 1 and 3, the chain 16 is coiled upon the shaft 1 and the turning effort exercised by the weight upon the shaft is a maximum since the force is applied at its maximum radius from the axis of the shaft.

The maximum radius of action of the turning effort on the shaft 4 is about one-third of the radius of the sprocket wheel as shown in Fig. 1, and the effective static forms at the moment of release of the sprocket wheel 8 is equal to half of the weight 20.

Neglecting friction and assuming that all moving parts of the mechanism are weightless except the weight 20, the upward acceleration of the tape would be about six times that due to gravity since the velocity of the chain 16 will be twice that of the weight and the radius of the "sprocket wheel 3 is about three times the radius of action of the turning effort at the moment of release of the mecha nism.

Assuming that the tape has to rise five feet, the time taken would be about seconds under the above conditions. Actually it has been found that the effective part of the rise of the tape can be considered from about nine inches above the starting position to five feet from the same point, giving a lift of four feet three inches. The time taken to accomplish this lift on the above assumptions is .1 1 seconds, but, in actual practice, the time is .23 seconds as stated above since the inertia and friction of the moving parts causes a reduc tion in velocity.

It will be understood that, as the chain 16 unwinds from the shaft 4:, the turning moment upon said shaft is reduced, since the radius ofaction of the actuating force gradually merges towards the axis of the shaft.

It will thus be seen that the acceleration of the tape is a maximum at the commencement of its upward travel, the acceleration being gradually reduced as the tape moves upwardly.

This deceleration of the tape is caused both by the unwinding of the chain 16 and by the operation of the friction brake mechanism which comes into operation early in the upward action of the tape.

The tape release mechanism is intended to be operated electrically but it will be understood that the mechanism may be manually operated.

For electrical actuation, the coils 86 of the magnets 85 of both masts are electrically connected with a source of electric energy, there being interposed in the connections a control switch which is situated at any point convenient for operation by the starter, e. g., the

" control switch may be placed in the starters pocket or behind his back so that his intentions may not be anticipated by the field or the spectators.-

On operation of the control switch the armature 88 of each mast is attracted upwardly against the pole faces 87 of the magnet 85 whereby the pawl 91 is moved into inoperative position and the sprocket wheel is released.

As the armature 88 is attracted upwardly the safety catch falls by gravity into position to maintain the armature in raised position and to maintain the pawl 91 in inoperative position clear of the rotating sprocket wheel.

Electrical actuation ensures that both armatures move concomitantly so that both ends of the tape rise simultaneously.

For manual operation, an operator is required at each mast so that at a given signal each operator may depress the relative safety catch handle 99 whereby to raise the armature 88 and to release the sprocket wheel as hereinbefore explained.

It will be evident from reference to Fig. 1 that the armature 88 may be manually operated directly by means of the handle 93 thereon, the safety catch falling by gravity into position to retain the armature in raised positon as soon as the protuberance 96 vacates the notch 98. In practice, it is found easier to operate the release mechanism through the medium of the safety catch lever 99 only.

Conveniently, the handles 93, 99 may be operated by one hand to en ect locking of the mechanism.

The operation of the friction brake mechanism is as follows Rotating together with the shaft 4 are the sleeves 45 and 19. Rotation of the sleeve 45 as the tape rises causes the friction brake member 52 to approach the rear face 3' of the sprocket wheel due to the movement of the nut 50 which is in screw-threaded engagement with the sleeve as already explained.

At a predetermined point in the upward travel of the tape the member 52 engages the face 3 whereby, on continued rotation of the sprocket wheel, the sleeve 45 is threaded rearwardly through the now stationary nut 50.

Rearward movement of the sleeve 15 is accompanied by compression of the springs 62, 63, the member 52 being thus forced against the sprocket wheel so as gradually to arrest the rotation thereof.

By allowing the braking mechanism to come into action early in the upward travel of the tape, the tape may be retarded gradually. The ideal adjustment of the braking mechanism is that which will permit the compression springs 62, 63 to be almost fully compressed when the tape comes to rest.

When the weight 20 is at the end of its descent the tape has not quite reached its full height so that, during the final part of the tape ascent, the weight is lifted slightly wherebv further to retard the upward movement of the tape. The extent to which this latter means of retardation should ,be used has been ascertained by practical tests over a wide range, even up to the limit where the braking mechanism will not retain the tape in its uppermost position and it returns to its positionof equilibrium.

The heavy spring 62 is responsible for the main braking pressure between the member and the sprocket wheel 3. The lighter spring63 also contributes to this pressure but its main function is to retain the cotter pin 59 in operative position in engagement with the .splined portion 60 of the sleeve 49.

As already explained, in the operation of the mechanism the sleeves 45, 49 rotate together with the shaft 4,, the sleeve 49 being engaged by the cotter pin 59. The sleeve is in continuous engagement with the sleeve 49 through the interdental engagement of the teeth 48, 61. It will be understood that, al though in the operation of the braking mechanism the sleeve 45 moves axially of the shaft 4, yet it is in continuous engagement with the sleeve 49.

To set the mechanism, i. e. to bring the tape to lowered position, the shaft 4 is rotated by means of the handle .15 in the direction to lower the tape and to raise the weight 20.

When the mechanism is in initial position, i. e. with the tape in lowered position and the weight raised, the handles 93 and 99 are operated to lock the sprocket wheel 3 against rotation.

It will be evident that, when the shaft4 is manually rotated to bring-the tape to lowered position, the braking member 52 will be retracted from engagement with the sprocket wheel and the springs unstressed.

Means are provided whereby the distance between the braking member 52 and the rear face 3 of the sprocket wheel 3 may be adj usted to compensate for wear in the braking member or to determine the point in the up ward travel of the tape at which the brake is to act. To effect this adjustment it will be evident from consideration of Fig. 5 that the sleeve 45 will require to be freed from the shaft 4 and rotated independently thereon whereby to move the member 52 towards or away from the face 3 of the sprocket wheel 3.

The sleeve-adjusting means include a tubular key (Figs. 21-24) having a body portion 100 unitary with which is a T head 101 for manual operation. Formed at the end of the body portion 100 remote from the T head are diametrally opposed prongs 102 adapted to engage the diametrally opposed notches 76 formed in the rear end of the sleeve 49. Adapted for fitment within the body 100 of the key is a rod 103 having a reduced end 104 contrived to project beyond the prongs 102 whereby to penetrate the aperture 74 in the shaft end cap 68 and to enter the bore of the sleeve 67.

Formed in the lateral wall of the key is a slot 105 near one end of which is a recess 106. A threaded aperture 107 formed near the inner endof the rod 103 is adapted to register with the slot 105 when the rod is in position within the key whereby a handle (not shown) may be inserted through the slot 105 and threaded into the aperture 107. WVhen the handle is engaged within the recess 106 in the slot105, the end 104 of the rod 103 projects from the "key to its greatest extent. When the prongs 102 are engaged with the notches 76, the handle on the rod 103 is pressed forwardly into engagement with the recess 106 whereby the end 104 of the rod penetrates the bore of the sleeve 67 and forces the pin 69 and therewith the cotter pin 59' forwardly within the shaft 4 in opposition to the compression springs 62, 63. In this position of the key, the cotter pin 59 is disengaged from the splines 60, being now in the annular recess 81 in the bore of the sleeve 49.

It will be seen that, in this position, the interconnected sleeves 49 and 45 may be rotated in either direction on the shaft 4 by retation of the adjusting key, whereby to effect adjustment of the distance between the braking member .52 and the rear face 3 of the sprocket wheel 3.

When the desired position of the braking member 52 is obtained, the handle controlling the position of the rod 103 is moved to the remote end of the recess 105 whereby to retract the rod from engagement withthe pin 69 within the sleeve 67. It may be found necessary now partly to rotate thesle-eve 49 until the cotterpin59 re-enters the splines under the thrust of the spring 63.

In operation, should the spring 62 break, it will be understood that the cotter pin 44 will be moved to thelimit of its travel within the slots 43 whereby effectively to bring the mechanismto rest.

The tape-holding arm (Figs. 18, 19 and 2.0) comprise a substantially horizontal frame 33 adapted to embrace the vertical guide rod 40 and provided at the front end with a gripper head 108 formed with a slot 109 adapted to receive one end of the tape. Provided at therear end of the arm is a. vertical limb 110 of which the top end 111 is attached to one end of the chain 32 and of which the other end is-fitted with a screw 112 (Fig. 1) 'adjustab'ly attached to a bar 113 integral with theframe 33,, beneath the limb 110, and formed with an aperture 114 for penetration by the screw 1'12.

115 denotes a V grooved roller ournalled on a pin 116 penetrating collinear apertures 117 (Figs. 1 8 20) formed in the tape-holding arm 33 near the rear end thereof.

As shown in Fig. 1, when the tape-holding arm 3'3 is in lowered position the roller 115 is spaced from the guide rod 40, but the arrangement is such that, due to a slight relative inclination between the chain 32 and the rod, the roller 115 in the upward travel of the tape moves towards the guide rod until it engages the rod whereby to guide the tapeholding arm towards the upper limit of its travel as shown in Fig. 2. The construction minimizes friction at the commencement of the upward travel of the tape, when acceleration is important, and provides guidance for the upwardly travelling tape-holding arms when the arms are in such a position that the chain 32 would tend to sag and to alter the tension of the tape.

Desirably, the casing 2 is adjustably mounted on the mast so that the tape level may be varied, if desired, on courses where horses and ponies are being raced alternately.

I claim 1. A starting gate for race courses, comprising two masts, tape-carrying arms movable on the masts, and tape-actuating mechanism for each mast said mechanism comprising a gravity-operated motor having a shaft rota-table to raise the relative tape-carrying arm, means for winding up said motorto set position, electrically and manually operable means for releasing the motor, and friction braking means adapted automatically to function during the rise of the tape whereby to bring the motor gradually to rest.

2. A starting gate as claimed in claim 1 including a motor, a shaft journalled for rotation on a horizontal axis, a sprocket wheel on said shaft, a substantially vertically disposed chain carrying a tape-holding arm, said chain wrapping said wheel, a second sprocket wheel journalled near the top of the mast and also wrapped by said chain, a weight guided for vertical movement, a chain sustaining said weight, a pin concentric with said shaft, said second mentioned chain anchored at one end to said pin and anchored at its other end above the weight to a point on the mast, so that, when the shaft is manually rotated to wind up the motor, the

weight-sustaining chain is coiled spirally upon itself about said shaft to raise the weight and to lower the tape-holding arm and, when the mechanism is released to permit upward travel of the tape to start the race, said chain uncoils spirally from said shaft.

3. A starting gate as claimed in claim 1 including friction braking means comprising a motor shaft having a hollow portion, a braking disc coaxial with said shaft, an externally screw-threaded sleeve rotatable with said shaft and slidable axially thereon, a nut disposed coaxial with and carrying said braking disc, and penetrated by said shaft, a helical compression spring located within said hollow portion and adapted to be compressed by axial movement of said sleeve, a sprocket wheel on said shaft presenting an engaging face spaced from said disc, means for rotating said sleeve on said shaft whereby to effect adjustment of the distance between said braking disc and said engaging face so as to determine the instant at which the brake mechanism is to function so that, at a predetermined point in the upward travel of the tape, the braking disc frictionally engages the sprocket wheel under the loading of the compression springs whereby gradually to arrest rotation of the shaft and to bring the tape to rest without shock at the upper limit of its travel;

4. A starting gate as claimed in claim 1, including electrically operated means for relasing the mechanism to raise the tape comprising electrically interconnected electromagnets one at each mast and connected to a source of electric energy, an armature, a pawl engageable with one of a series of protuberances formed on the periphery of the sprocket wheel on the motor shaft whereby to re lease the mechanism, and adapted on attraction of the armature by the magnet to be withdrawn from engagement with said sprocket wheel, a safety catch arranged, when said armature is attracted by the magnet, to move by gravity into a position such as to maintain the armature in inoperative position, so that, when the magnet is de-energized, the pawl will be restrained from fouling the rotating sprocket wheel and an operating switch or the like located for convenience of operation by the starter in a position out of the vision of the field and spectators.

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

CHARLES BUCHANAN MAUCHAN.

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