US2322899A - Automatic timing device - Google Patents

Description

June 29,1943. H. A. WAGNER 2,322,899

AUTOMATIC TIMING DEVICE Filed July 28, 1941 2 Sheets-Sheet 1 HAROLD A. WAG/Y5K INVENTOR.

ATTORNEY June 29, 1943. H, A, WAGNER I I 2,322,899

AUTOMATIC TIMING DEVICE Filed July 28, 1941 2 Sheets-Sheet z HAROLD A WJGNER INVENTOR.

ATTORNEY Patented June 29, 1943 UNITED STATES PATENT. OFFICE 2,322,899 AUTOMATIC TIMING DEVICE Harold A. Wagner, Portland, Oreg. Application July 28, 1941, Serial No. 404,305

7, Claims.

The present invention relates to automatic timing devices, and, while it is not necessarily to .be limited thereto, it is particularly adaptable for timing'the operation of a rotary machine.

With certain types-of machines, such as concrete mixers, it is desirable to provide a timing device which will be automatically energized upon the loading of the machine and will prevent premature unloading thereof to insure a conformity of the product with certain standards. Such devices as have been proposed heretofore involve relatively complicated mechanisms of a delicate nature and are not only prohibitively costly but are unreliable in operation under severe conditions of service.

It is an object of the present invention to provide a new and improved timing device of the type described which comprises relatively few parts of simple design and of low cost manufacture. i

It is a further object of the invention to provide a new and improved timing device which is particularly applicable for timing the operation of a rotary machine such as a concrete mixer, the device consisting of rugged parts capable of reliable performance under severe operating conditions.

It is a still further object of the invention to provide a new and improved timing device of the type described which is so constructed and arranged that the period of operation may readily be adjusted without requiring the use of any tools. a

, Further objects and advantages of the invention will appear fromthe following description, taken in connection with the accompanying drawings, while the features of novelty will be pointed out with greater paricularity in the appended claims.

In the drawings, Figure 1 is a partial side view of a concrete mixer equipped with a timing device constructed in accordance with the present invention; Figure 2 is a front elevation of the timing device illustrated in Figure 1 with the cover thereof removed; Figures 3 and 4 are enlarged fragmentary views of the timing device illustrating the operation thereof; Figures 5 and 6 are cross sectional views of the timing device, taken along the lines 5-5 and 6-6, respectively, of Figure 2; and Figure 7 is an enlarged cross sectional view of a portion of the timing device, taken-along the line of Figure 2.

The timing device of the present invention will be described as it may be applied to a rotary machine such as a concrete mixerfor determining the period of operation thereof, though it will readily be understoodas the description proceeds that the timing device may be adapted for use with other machines. v

The concrete mixer, shown partially in Figure 1, may be of any suitable type comprising a rotatable drum 10, a feed trough II, and a discharge spoon I 2. Materials to be mixed may be fed into the drum I0 by means of. a suitable skip I 3 having rollers l4 cooperatively arranged on an inclined track l5 which track is supported at its upper end to an upright; I6 of the mixer framework l1. As the skip I3 is moved upward- -l'y along the inclined track l5 and to the drum charging position, the wheels id drop into the notches l8 provided in the tracks I5. The skip is then pivoted about the axis of therollers ll to a substantially upright position as shown by the dotted lines [3, to dump the material loaded therein into the feed trough H which will direct it into the drum I0. It will be understood that the drum I0 is in operation during the time of the loading thereof. 9

The discharging spoon I2, shown in the inoperative position, is connected through linkage Hi to an operating lever 2| suitably mounted on an extension 22 of the framework. By manipulation of the lever 2|, the spoon l2 may be tilted downwardly to effect unloading of the mixed batch from the drum l0, g V

In order to prevent premature unloading of thedrum, a timing device, indicated, generally at 25, is provided and which is setinto operation upon the charging of the drum simultaneously locking the discharge control lever 2| in the inoperative position, and maintaining it inoperative until the drum has made a requisite number of revolutions insuring a propermlxing of the batch therein. The timingdevice 25, mounted by means of suitable lugs 26 upon the mixer framework, includes a control bar 21 extending through the upper portion of the timer casing and mounted for longitudinalmovement therein. In the released condition of the timer the control bar 21 is in the position illustrated in fullline. The left end of the timer control bar 21 is connected by a link 28 to one arm 29 of a bell crank suitably pivoted as at 30 to the mixer frame member IS. A second arm 3| of the bell crank extends adjacent the skip track l5 and is adapted to be engaged by one of the skip rollers I4 as it drops into the notch 18 upon the unloading thereof into the mixer drum 10.

Upon engagement of the bell crank arm 3| by the skip roller H, the bell crank is rotated in the counterclockwise direction as viewed in Figure 1 and through link 28 the timer control bar 21 is moved thereby toward the right. Extending from the right end of the timer control bar 24 is a rod 32 slidably arranged in a boss 33 and having an outer end adapted to be moved into a locking engagement with the control lever 2| upon movement of the control bar 21 to the right. Once the control bar 21 has been shifted to the set or locking position by a dumping of the skip, it is retained in such position by mechanism included in the timer 25, permitting a lowering of the skip l3 for Depending downwardly from the timing device 25 is an operating arm 35 provided with a roller 35 on the end thereof and which is adapted to be cooperatively engaged by a cam 31 secured to the side of the drum II]. The cam 31 in engaging with the roller 35, once of the drum, gives it a kick to the left and which movement is transmitted to the timer mechanism. After a predetermined number of revolutions of the mixer drum have been counted by the timing device, the --control bar 21 is released for movement' to the left, thereby unlocking the control lever 2| for the discharge spoon l2.

Referring now more particularly to Figure 2, which illustrates the timing device with the cover thereof removed, the device comprises a sheet metal'casing 38 of a generally rectangular configuration. The control bar 21 is slidably mounted for movement in the longitudinal direction adjacent the upper wall of the casing 38, its 'mov'ementbeing guided by suitable guide blocks '39 and ili'adjacent the opposite ends thereof. The control bar 21 is biased in the releasing direction, or to the left 'as viewed in Figure 2, by means of a'spring 4|, the left end of which may be anchored to the casing 'as at 42 while the right end is secured to a suitable point 43 on the bar 21. The bar 21 when moved to the set position, or to the right, is retained in such position by means of a latch 44 pivoted to the casing as at 45. The latch 44 is adapted cooperatively to engage with a lug 45 depending downwardly from the control bar 21, the latch 44 being biased upwardly or toward the control bar by means of a suitably arranged spring 41. The latch 44 is provided with a depending 'arm 43 which is adapted to be means at the end of a engaged by a notching predetermined period of operation of the mixer to effect the disengagement of latch 44 and to permit the control bar 21 to be moved to the left the reloading thereof,

during each revolution is provided with an extension cured thereto and which extends in a generally parallel and spaced relation therewith. The operating lever is pivotally mounted on the timer casing by means of a pin 58 extending through the bifurcated end thereof, the outer end of the pin 58 being supported in a suitable bracket arm 59. The upper end of pawl 54 is pivotally mounted upon the transverse pin 5| extending between the upper ends of the operating lever, the lower end of the pawl being biased into engagement with the teeth of the rack bar 49 by suitable means such as a weight 62 provided thereon. The upper end of dog 55 is pivotally mounted on the pin 58 between the bifurcated ends of the operating lever, while the lower end thereof is biased into engagement with the teeth on the rack bar to hold it in the position to which it has been moved by operation of the pawl 54. The dog 55 63 opposite the tooth end thereof and which extension is adapted to be cooperatively engaged by a cam 54 provided on the control bar 21. The dog 55 is biased in the clockwise direction by means of a spring 55 connected between the extension 53 and the control bar 21 so that the tooth thereof is resiliently held in engagement with the teeth of the rack bar. The operating lever of the timer is biased in the counterclockwise direction by means of a spring 56, one end of which'is suitably anchored as at 51 to the operating lever below the pivot 58 thereof and the other end to a suitable point 58 on the casing whereby the roller 35 at the outer end ofthe lever is normally held in the path of the cam 31 on the mixer drum.

Referring now more particularly to Figure 3,

the operation of the device thus far described is as follows. Upon engagement of the operating lever by the cam on the mixing drum the lever will be pivoted about the pin 58 in the clockwise direction, shifting the pawl 54 and hence the rack bar 29 to the right by a distance correspending to the length of one tooth of the bar.

or to the releasing position under the force of spring 4|.

The notching means comprises a longitudinal rack bar 49 slidably mounted upon the. lower wall of the casing 38, its movement being guided in a direction substantially parallel with the control bar 21 by means including suitable guide blocks 5| and'52. The rack bar 49 is-vbiased toward the left by means of a suitable spring 53, the left end of which is anchored to the timer casing and the right end to the rack bar 49.

Therack bar 49 is provided with a plurality of teeth along its upper surface and which are adapted to be cooperatively engaged by a pawl 54 and a dog 55 The pawl 54, is adapted to be operated by the operating lever 35 depending from the timer for effecting a stepby step or notohing movement of the rack bar toward the right and into engagement with the latch arm 48. Referring more particularly to the view of Figure 5, the operating lever 35 is bifurcated at its upper end, a second strip portion 51 being se- During this movement of the pawl 54 the deg F 55 will slide up out of the tooth slot in which it had been seated and drop into the next succeeding tooth slot. Upon the pssage of the cam 31 past the roller 35 the operating lever will be restored to its normal position by the spring 66 and the pawl 54 will be shifted back, whereupon it will drop into the next tooth slot under the force of the biasing weight92. Following a predetermined number of revolutions of the mixer drum, the right end of the rack bar 49 will be moved into engagement with the depending latch arm 48 and pivot it in the'counterclockwise direction as indicated more clearly in Figure 4, in which position the latch 44 will be moved free of the lug 46 to permit the control bar 21 to move to the releasing position under the force of its biasing spring 4|,

Upon movement of the control bar 21 to the releasing position, or to the left, the cam 64 will engage with the end of the extension 63 of dog 55 to pivot it in the counterclockwise direction about the pin 58. Movement of dog 55 in this direction will cause its tooth'end to be lifted out of engagement with the rack bar 49 and into engagement with theunder surface of the pawl 54, thereby shifting it also to the inoperative or disengaged position relative to the rack bar. The rack bar will-then befreed to move to the reset position, orto the left, under the force of its biasing spring 53.

The operating period of the mixer is determined by the extent to which the'rack bar is permitted to return into a reset position away from the latch arm' 48. In order to effect'ad- Justment of the operating period, an adjustable stop ll is provided for the rear end of the rack bar 49. As illustrated more clearly in Figure 7, the adjustable stop arrangement includes atooth bar 13 arranged parallel with and adjacent the longitudinal line of travel of the rack bar 49 and defining a guideway therefor. The teeth on the bar 13 are preferably of the same pitch as the teeth on the rack bar 49. The-adjustable stop II is provided with a plurality ofteeth along one edge thereof for meshing cooperativelywith the teeth on the bar 13 so that when it is dropped into position it is firmly held therein. The bar 13 may be calibrated in accordance with the number of teeth on the rack bar -49 and which will" correspond with the range of revolutions to be made by the mixer drum. By moving the stop H to the left, the rack bar 49 will be permitted to move farther away from the latch arm '48 in the reset position and hence the length of travel which will be required thereof to effect engagement with the latch arm will be increased. Similarly, by moving the stop ll to the right, the operating period for the mixer drum may be shortened. The stop H may be secured to the casing by a flexible lead such as a chain 14' and by means of which it may readily be liftedfrom one position and inserted in another. It will be obvious that no tools will be required for effecting such an adjustment and which can furthermore be performed in a minimum amount of time.

, 'Afsuitable batch counter 15 may be provided in the casing of the timer for counting the number of successive batches of concrete mixed in the machine. As, shown, the counter may be mounted for actuation by an extension of the latch arm 44 so that upon each releasing movement thereof the counter will be shifted one digit.

An audible indicator may also be provided in 45 conjunction with the timing device in the form of a bell 16 which may be attached to the rear of the timer casing in any suitable manner. The hammer (not shown) for the bell 16 may be actuated by any suitable means such as lug 11 extending rearwardly through the slot 18 in the rear wall of the timer casing. Upon movement of the control bar to the left following release thereof, the lug 11 may engage with the bell hammer-to give a signal to the machine operator indicating the completion of the operating cycle.

Upon movement of the control bar 21 to the I releasing position, the lever 2| is unlocked, whereupon the discharge spoon I2 may be shifted thereby to the unloading position. Since operation of the lever 2! is precluded until release thereof by the timing device, a uniform mix of the concrete batch will be insured and the element of human error is eliminated from the operation of the machine.

The timing device as described involves relatively few working parts and which, furthermore, are of relatively simple design so that they may readily be made of rugged proportions so as to be capable of withstanding rough usage to which machines such as concrete mixers are accustomed to receive. The operation of concrete mixers inherently entails a dust laden ambient atmosphere, and such machines are, furthermore, usually left unprotected outdoors in all types of weather. My timing device, how-'- ever, willnot become fouled by accumulations of dust, water or snow, and the casing need be merely tight enough to keepirocks andcoarse sand out of the working mechanism; Ice will not substantially interfere with the operation of the device. Upon loading of the mixer, a force is imparted through the bell crank 29, 3|- to move the control bar 21' to the set position, which is sufficiently great as will effect the breaking loose thereof from any ice encrustations. Similarly, the rack bar 49, having been reset at the completion of the last preceding cycle of operation of the machine, is in readiness for forward notching by means of the pawl 54. Since the driving pawl 54 is actuated through a relatively long lever arm, a frozen rack bar 49 will readily be broken loose from the casing. Once broken free, the rack bar will operate smoothly to the end of its stroke, after which it'will immediately be returned to the reset position. The pawl54 may be made from relatively wide and heavy stock so that it will possess sufficient strength for transmitting the required force between the operating lever and therack bar.

While the timing device of the invention'has been described in connection with a concrete mixer, it will be obvious to those skilled in'the art that the device may readily be applied to other types of machines in which it is desired to look a particular portion of the machine until a'predetermined cycle of operation has been completed by another part thereof.

Having described the invention in what is con"- sidered to be a preferred embodiment thereof, it is desired that it be understood that the specific details shown are merely illustrative, and that the invention may be carried out by other means.'

What I claim'is:

1. 'A timer comprising a longitudinally movable control bar, means biasing said bar to a releasing position, said control bar being movable to a set position against the force of said biasing means, a pivoted latch for cooperatively engaging said control bar and retaining said bar in the set position, a longitudinally movable rack bar, said latch being mounted in said casing beyond one end of said bar, means biasing said rack bar away from said latch, notching means for engaging said rack bar and moving said one end of said rack bar into engagement with said latch for effecting the disengagement of said latch from said control bar, operating means for said notching means, means responsive to the release of said control bar for shifting said notching means to an inoperative position to permit resetting of the rack bar by the biasing means associated therewith.

2. A timer comprising a control member, means biasing said control member to a releasing position, said control member being movable to a set position against the force of said biasing means, a latch for engaging said control member for retaining said member in the set position, a rack bar, said latch being pivotally mounted in said casing beyond one end of said rack bar, means biasing said rack bar away from said latch, means for notching said rack bar into engagement with said latch and causing the disengagement of said latch from said control member, operating means for said notching means, and means on said control member for operatively engaging said notching means upon the release of said control member for shifting said notching means to an inoperative position to permit resetting of said rack bar by the biasing means associated therewith.

3. A timer comprising a control member, means biasing said control member to a re1easing position, means for moving said control mem her to a set position against the force of said biasing means, a latch for retaining said control member in the set position, a longitudinal rack bar, said latch being mounted in said casing beyond one end of said rack bar, means biasing said rack bar away from said latch, notching means for moving said one end of said rack bar toward said latch and into engagement therewith vfor efiecting release of said control member, operating means for said notching means, means operatively associated with said notching mean-s and adapted to be operated by said control mem- -bEI' upon the release thereof to move said notching means to the inoperative position permitting resetting of said rack bar by the biasing means associated therewith, and adjustable stop means for limiting movement of said rack bar away from said latch.

4. A timer comprising a control member, means biasing said control member to a releasing position, said control member being adapted to be moved to a set position against the force of said biasing means, a pivoted latch for cooperatively engaging and retaining said control member in the set position, a longitudinal rack bar, said latch being mounted in said casing beyond one end of said rack bar, a pawl for cooperatively engaging said rack bar, means biasing said rack bar away from said latch, an operating lever for said pawl whereby said one end of said rack bar may be moved toward said latch and into engagement therewith for effecting release of said control member, a dog for cooperatively engaging said rack bar for preventing movement thereof away from said latch, means on said control member for shifting said dog and said pawl to the inoperative position upon the release of said control member, said rack bar being movable to the reset position by the biasing means associated therewith upon movement of said dog and said pawl to the inoperative position.

5. A timer comprising a casing, a longitudinally movable control bar mounted in said casing, a spring connected between said bar and said casing biasing said bar to a releasing position, said control bar being adapted for movement to a set position against the force of said biasing,

means, a latch for cooperatively engaging said control bar and retaining said bar in the set position, a longitudinal rack bar, said latch being pivotally mounted in said casing beyond one end of said rack bar, means biasing said rack bar I lease of said control bar, lever operating means pivotally connected to said pawl, a dog for en-. gaging said rack bar and preventing reverse movement thereof, means on said control bar for operatively engaging said dog upon the release of said control barand shifting said dog and said pawl to an inoperative position relative to said rack bar, said rack bar being movable to a reset position upon movement of said dog and said pawl to the inoperative position, and stop means for predetermining the reset position of said rack bar.

6. A timer comprising a casing, a longitudinally movable control bar mounted in said casing, means biasing said control bar to a releasing position, said control bar being adapted for movement to a set position against the force of said biasing means, a latch mounted on said casing and adapted to cooperatively engage said control bar and retain said control bar in the set position, a rack bar mounted for longitudinal sliding movement in said casing, means biasing said rack bar to a set position away from said latch means, notching means for shifting said rack bar step by step toward said latch means and into engagement therewith for eilecting release of said control bar, lever operating means pivotally connected to said notching means, a cam on'said control bar for operatively engaging said notching means upon the release of said control bar and effecting movement thereof to an inoperative position, said rack bar being movable to a reset position by the biasing means associated therewith upon movement of said notching means to the inoperative position, adjustable stop means for predetermining the movement of said rack bar in the resetting direction.

'7. A timer comprising a casing, a control bar extending through said casing, means engaging one end of said bar for movinng the other end thereof to a locking position, spring means biasing said bar to a releasing position, latch means for retaining said bar in the locking position, a rack bar slidably arranged in said casing, spring means biasing said rack bar away from said latch means, means for notching said rack bar into engagement with said latch, a cam projecting from said control bar for engaging and shifting said notching means to an inoperative position upon release thereof, a toothed bar defining a guideway for said rack bar, and a toothed stop block adjustably insertable into said guideway for limiting movement of said rack bar away from said latch.

HAROLD A. WAGNER,

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