US2805293A - Percentage timing device - Google Patents

Description

P 1957 R. L. DAUGHERTY 2,805,293

PERCENTAGE TIMING DEVI CE.

Filed Dec. 16, 1955 l 25 v J z a a United States Patent Ofiice 2,805,293 Patented Sept. 3, 1957 PERCENTAGE TIMING DEVICE Robert L. Daugherty, Reedsburg, Wis., assignor to Hankscraft Company, Reedsburg, Wis., a corporation of Mscousin Application December 16, 1955, Serial No. 553,545

9 Claims. (Cl. 200-31) This invention relates generally to an input controller for electric circuits and more particularly to an adjustable device for regulating the relative time of power on and power off in the supply of current to an electric load.

Many devices have been proposed for controlling an electric circuit in the described manner, but these devices have been subject to a number of disadvantages in that they have generaliy been characterized by complex constructions employing a relatively large number of moving parts with the result that they have been subject to frequent operational failures and have been diflicult to install and maintain in operation. The principal object of the present invention, therefore, is to provide a circuit controller of the type indicated above which is rugged, of simple construction, and yet is eificient in operation, thereby rendering the device capable of convenient installation, repair and replacement.

The invention both as to its organization and method of operation, together with further object and advantages, will be best understood by reference to the accompanying drawings wherein:

Fig. 1 is a front view of the face plate of the device;

Fig. 2 is an enlarged side elevati-onal view of the de vice with a few of the component elements broken away to facilitate the illustration;

Pig. 3 is a setional View taken along a line substantially corresponding to line 3-3 of Fig. 2;

Fig. 4 is a sectional view looking in the direction of the arrows 44 in Fig. 2;

Fig. 5 is an enlarged sectional and fragmentary v1ew taken along a line substantially corresponding to line 5-5 in Fig. 1; and

Fig. 6 is an enlarged and exploded perspective view of the cams for use in a device characterized by the features of the present invention.

In accordance with the present invention, the foregoing and other objects are realized by providing a timing device including a support shaft for an assembly axially slidable therealong. This assembly includes a driven cam for operating an electric switch controlling the input to an electric circuit associated with the timing device, together with a holding disk for maintaining the switch in its operated position. In order to release the switch to establish the circuit off position, there is provided a manually adjustable cam which may be moved to any desired angular position with respect to the driven cam. Indexing means are provided to hold the manually adjustable cam in each of its angular positions with the result that the manually adjustable cam is actually held in. fixed position with respect to the driven cam. By altering the position of the fixed cam with respect to the driven cam, the time of switch closure for each complete revolution of the driven cam may be regulated and, ac cordingly, the percentage of circuit on to circuit off conditions may be controlled.

Specifically, and referring particularly to Figs. 1 to 6 of the drawings, an illustrative embodiment of the invention is there shown which includes a pair of circular plates 10 and 11 disposed generally parallel to each other and held in spaced apart relationship by means of spacing studs 12, 13 and 14. The latter studs are suitably fastened to the plates 10 and 11 as by means of small screws 15 passing through each of the plates and into engagement with internally threaded, axial bores in the studs. The plates 10 and 11 and the studs 12, 13 and 14 thus cooperate to form a supporting framework indicated generally at 16 for the other elements of the timing device to be described hereinafter.

For the purpose of driving the driven elements of the device in the manner described below, there is mounted on the rearwardly disposed side of the plate 11, a synchronous motor 17 and a gear reduction mechanism 18 of conventional construction. Electric current is supplied to the motor 17 by means of current conductors 19 and 20 in order continuously to excite the motor throughout a particular timing cycle. The output of the gear reduction mechanism 18 is taken from a stub shaft 39 protruding through an opening in the rear plate 11 and accommodating on its free end a drive gear 21 meshing with a pinion gear 22 carried by a shaft 20 supported upon the plate 11. The pinion gear 22 forms one element of a sliding assembly, indicated generally as 23,

, which is slidably mounted upon and rotatable about the shaft 20. The sliding assembly 23 further comprises a disk 24 disposed adjacent the gear 22 and a driven cam 25 adjacent the disk 24. The latter cam is generally circular in shape and has a radius considerably less than that of the disk 24. As best shown in Fig. 6, the cam 25 includes a radial projection 25a extending outwardly a small distance beyond the periphery of the disk 24, as well as an axial projection 25b extending toward the front plate 10 and displaced 180 degrees from the radial projection. The axial projection is preferably formed by deforming a small segment of the peripheral portion of the cam 25 to provide an inclined camming surface 25c and an abrupt end portion 25d. In order normally to urge the sliding assembly 23 toward the front plate 10, a coil spring 27, best shown in Figs. 2 and 5, encircles the extreme rear end portion of the shaft 20 and is disposed between the gear 22 and the rear plate 11.

For the purpose of controlling current flow to the electric circuit associated with the timing device of the present invention, there is provided a single circuit controlling switch 29 secured to the rear plate 11 in any suitable mmanner as by the elongated screws 28 passing through the body of the switch and into engagement with threaded openings in the rear plate 11. In order properly to position the switch 29 with respect to the sliding assembly 23, there may be provided annular spacing rings 30 encircling the lower end of the elongated screws 28 and interposed between the rear plate 11 and the body of the switch. The switch 29 is preferably a micro switch having output leads 32 and 33 electrically connected to the input of the circuit to be controlled. The switch is operated by depressing a spring biased plunger 31 having its free end in engagement with a switch operating member 34 mounted for pivotal movement about a pivot pin 29a carried by the switch. The switch operating member 34 includes an elongated arm 34a having its upper surface as viewed in Figs. 3 and 4 in engagement with the plunger 31 and having its under surface riding upon the cam and disk of the sliding assembly 23. The spring biased plunger, of course, urges the arm 34a into continuous engagement with this cam and disk.

In view of the foregoing description it will be recognized that as the gear 22 is driven by the motor 17 in a clockwise direction as viewed in Fig. 3, the radial projection 25a on the cam 25 will eventually engage the arm 34a to pivot it in a clockwise direction about the the result that the coil spring 27 expands to move the.

sliding assembly forwardly along the shaft from the solid line position to the broken line position shown in Fig. 3. As the sliding assembly 23 is moved forwardly or to the right, the operating arm 34a will overlie the disk 24 and, consequently, after the radial projection 25a has been rotated past the switch operating arm, the latter will rest upon the disk 24. In this latter position the switch operating plunger 31 is depressed and the circuit controlled by the switch 29 is closed. This circuit on position will be maintained as long as the arm 34a remains in engagement with the periphery of the disk 24 and, consequently, it can be seen that the disk and its associated elements provide a holding means for maintaining the switch 29 in closed or on circuit condition.

To provide means for moving the sliding assembly 23 rearwardly along the support shaft 20 in order to establish an off circuit condition, there is provided a manually adjustable assembly indicated generally at 40. This assembly includes a shaft 41 having a hollow end portion 41a telescoping the outer end of the support shaft 20. On the extreme inner end of the shaft 41 there is fixedly mounted a circular cam 42 secured to a sleeve 43 encircling the shaft 41. The cam 42 is provided with an axial projection or tab 42a facing the axial projection or tab 25b on the cam 25. The projection 42a, like the projection 25b, is preferably formed by cutting out a small peripheral section of the cam 42 and bending this section so that it has an abrupt end 420 and a surface 42b inclined somewhat with respect to the face of the cam 42. As illustrated in Figs. 2 and 5, the shaft 41 extends through the front plate 10 and receives on its outer end a knob or pointer 44. To facilitate securing the knob to the shaft, the latter may be provided with an end portion 41b of substantially D-shape having a flat surface against which a set screw or the like may be pressed. The knob 44 is preferably provided with an indicating marker 44a cooperating with a graduated scale 45 carried upon a front plate 46 in order to indicate the various positions to which the manually adjustable assembly may be rotated. As indicated in Fig. 1, the graduations on the scale run from O to 100 corresponding to the percentage of circuit on conditions during any particular operating cycle. The graduated scale 45 is suitably secured to the front plate 46 as by machine screw 48 which passes through the plate 46 and into engagement with a threaded opening in the plate 10. Additional screws 49 may be provided to secure the front plate 46 to the plate 10 and, if desired, spacers 50, best shown in Fig. 2, may be employed surrounding the screws 48 and 49 in order to separate these two plates.

In order to index the manually adjustable assembly 40 in each of its angular positions, there is mounted on the shaft 41 a ratchet 51 in the form of a relatively large wheel having a series of peripheral teeth for engagement with a pawl 52 pivotally mounted on the stud 13 as best shown in Fig. 4. To maintain the pawl 52 in engagement with the ratchet 51, there is provided a 'spring 53 coiled about the stud 13, having one end retained within an indentation 52a in the pawl 52 and having its other end disposed within a suitable opening 10a in the plate 10.

Referring now to the operation of the timing device described above, it will be observed that the manually adjustable means 40 may be rotated to any desired position in order to fix the position of the axial projection 42a with respect to the axial projection 25b on the cam 25. Assuming purely for purposes of illustration that current flow to the load is desired during one-half of the entire timing cycle, the manually adjustable assembly 44 is rotated until the marking 44a on the knob 44 is brought into alignment with the 50 graduation of the scale 45 at which time the fixed cam 42 is so positioned that its axial projection 42a lies adjacent the switch operating member 34 in a position displaced approximately degrees in a counterclockwise direction from the position which it occupies in Fig. 4. Thus, the projection 42a will lie along the vertical axis in its extreme upper position as viewed in Fig. 4. As the sliding assembly 23 is rotated by the motor 17, the radial projection 25a of the cam 25 is moved to its vertical position where it is aligned with the projection 42a at which time the radial projection engages the switch operating member 34 to close the switch 29 in the manner described above. At the same time, the switch operating member 34 is seated upon the periphery of the disk 24 to maintain the switch closed. Thus, as the sliding assembly continues to rotate, the switch 29 remains closed until the inclined surface 250 of the axial projection 25b rides upon the inclined surface 42b of the projection 42a. The latter action occurs only when the radial projection 25:: has been rotated degrees from its switch closing position. When the axial projections 25b and 42a engage, the sliding assembly 23 slides axially along shaft Zii and moves from the broken line to the solid line position shown in Fig. 5 against the action of the coil spring 27. Axial movement of the sliding assembly to the rear causes the switch operating member 34 to be unseated from the disk 24 with the result that the spring biased plunger 31 moves the operating member from the broken line to the solid line position shown in Fig. 4 at which time it engages the periphery of the cam 25.

The edge of the switch operating member 34 engages the flat surface of the disk 24 to retain the coil spring in compression and prevent it from returning the sliding assembly 23 to its forward position. Movement of the switch operating member 34 to the solid line position, of course, opens the switch 29 by releasing the spring biased plunger 31 and the switch remains open for the succeeding 180 degrees of rotation of the sliding assembly 23 or until the radial projection 25a is again brought into engagement with the switch operating member 34. In View of the foregoing description, it will be apparent that when the manually adjustable assembly 40 is indexed in the fifty percent position, the switch 29 is closed for exactly one-half of each complete revolution of the sliding assembly 23 and current flow to the load is effected for fifty percent of each operating cycle.

As a second illustration of the operation of the device illustrated in the drawings, let it be assumed that current flow to the load is desired for approximately seventyfive percent of the operating cycle in which case the knob 44 is rotated until marker 44a is aligned with the 75 graduation on the scale 45. At this time, the cam 42 occupies the position shown in Figs. 2, 4 and 6 with its axial projection lying along a horizontal line passing through the axis of shaft 41. Switch 29 is again closed by engagement of the radial projection 25a with the switch operating member 34 and the operating member is held in closed position by the disk 24. When the radial projection 25a engages the switch operating member 34, the axial projection 25b is positioned at its extreme lower position along a vertical line passing through the axis of shaft 20. The disk 24 maintains the switch operating member in circuit closing position until the axial projections 25b and 42a meet an event which will occur only when the sliding assembly 23 has been rotated 270 degrees from the switch closing position. Engagement of projections 25b and 42a unseats the switch operating member .34 from the disk 24' and permits spring biased plunger 31 to open the switch 29 in the manner described above. The switch remains open for the succeeding 90 degrees of rotation of the sliding assembly 23 or until the radial projection 25a again engages the switch operating member 34. Thus, with the described setting of the manually adjustable assembly in its 75 percent position, switch 29 is closed for exactly three-fourths of the time required for each complete revolution of the sliding assembly 23 and current flows to the load for seventy-five percent of each operating cycle.

In view of the foregoing description, it will be apparent that, by proper setting of the manually adjustable assembly 40, current flow to the load may be effected for any desired portion or percentageof the operating cycle. Moreover, it will be observed that the device for effecting the result is structurally simple and can be manufactured, maintained and installed at minimum cost.

While a particular embodiment of the invention has been shown and described, many modifications will occur to those skilled in this art and it is therefore contemplated to cover by the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a percentage timer for use in an electric circuit to control the proportionate time of circuit on and circuit ofi conditions during a particular operating cycle, an electric switch establishing the circuit on and circuit off conditions, a switch operating member movable between different operating positions to open and close said switch, a first cam means including a cam surface engaging said operating member to move it to a first of said positions in order to operate said switch and establish one of said circuit conditions, means for driving said first cam means throughout the operating cycle, a holding member adjacent said first cam means and rotatable therewith for engaging said operating member to hold it in said first position, means including a second cam means cooperating with said first cam means to render said holding member ineffective to hold said operating member and to move said operating member to the other of its operating positions, and manually operated means for varying the position of said second cam means relative to said first cam means in order to adjust the time during which said holding member is effective to maintain said operating member in said first position, thereby controlling the proportionate time of circuit on to circuit 0 conditions.

2. In a percentage timer for use in an electric circuit to control the proportionate time of circuit on and circuit off conditions during a particular operating cycle, an electric switch establishing the circuit on and circuit off conditions, a switch operating member movable between different operating positions to open and close said switch, a first cam means including a cam surface engaging said operating member to move it to a first of said positions in order to operate said switch and establish one of said circuit conditions, a disk adjacent said first cam means and rotatable therewith having its periphery engageable with said operating member to hold the operating member in said first position, means including a second cam means cooperating with said first cam means to move said operating member out of engagement with said disk and to the other of its operating positions, and manually operated means for varying the position of said second cam means relative to said first cam means in order to adjust the time during which said disk is effective to maintain said operating member in said first position, thereby controlling the porportionate time of circuit on" to circuit off conditions.

3. The apparatus defined by claim 2 wherein said first cam means is a generally circular member having a radius less than that of the disk and said cam surface 6 comprises a radially extending projection extending be yond the periphery of the adjacent disk.

4. In a percentage timer for use in an electric circuit to control the proportionate time of circuit on and circuit off conditions during a particular operating cycle; a supporting shaft; an electric switch establishing the circuit on and off conditions; a switch operating member movable between different positions to open and close said switch; an axially slidable assembly mounted on said shaft and including a disk and a first cam means, said first cam means including a first radially extending projection and a second axially extending projection; means for driving said sliding assembly throughout the operating cycle; means biasing said switch operating member into engagement with the periphery of said first cam means; second cam means having an axially extending projection facing the axially extending projection of said first cam means; manually operated means for rotating said second cam means to adjust the position of the axially extending projection of the second cam means; the radial projection on said first cam means being effective to engage said operating member as said sliding assembly is driven in order to raise the operating member above said disk; and means for urging said sliding assembly toward the second cam means in order to seat the operating member on the periphery of said disk whenever the operating member is raised by said radially extending projection, thereby to establish one of said circuit conditions; the axial projections on said first and second cam means being engageable to force said sliding assembly axially away from said second cam means as said sliding assembly is driven, thereby to unseat the operating member from said disk and permit said biasing means to move the operating member into engagement with the second cam means in order to establish the other of said circuit conditions.

5. In a percentage timer for use in an electric circuit to control the proportionate time of circuit on and circuit 0 r conditions during a particular operating cycle; a supporting shaft; an electric switch establishing the ircuit on and off conditions; a switch operating member movable between different positions to open and close said switch; an axially slidable assembly mounted on said shaft and including a disk and a first cam means of generally circular shape but having a radius less than that of said disk, said first cam means including a first radially extending projection and a second axially extending projection; means for driving said sliding assembly throughout said operating cycle; means biasing said switch operating member into engagement with the periphery of said first cam means; second cam means having an axially extending projection facing the axially extending projection of said first cam means; manually operated means for rotating said second cam means to adjust the position of the axially extending projection of the second icam means; the radial projection on said first cam means being effective to engage said operating member as said sliding assembly is driven in order to raise the operating member above said disk; and means for urging said sliding assembly toward the second cam means in order to seat the operating member on the periphery of said disk whenever the operating member is raised by said radially extending projection, thereby to establish one of said circuit conditions; the axial projections on said first and second cam means being engageable to force said sliding assembly axially away from said second cam means as said sliding assembly is driven, thereby to unseat the operating member from said disk and permit said biasing means to move the operating member into engagement with the second cam means in order to establish the other of said circuit conditions.

6. A percentage timer for use in an electric circuit to control the proportionate time of circuit on and circuit off conditions during a particular operating cycle comprising a frame including a pair of interconnected spaced plates; driving means mounted on said frame; a support shaft carried by the frame; an el ctric switch carried by the frame for establishing the circuit on and off conditions; a switch operating member movable between different positions to open and close said switch; an assembly slidably mounted on said support shaft and driven by said driving means, said sliding assembly including a disk and a first cam means, said first cam means including a first radially extending projection and a second axially extending projection; means biasing switch operating member into engagement with the periphery of said first cam means; second cam means having an axially extending projection facing the axially extending projection of said first cam means; manually operated means for rotating said second cam means to adjust the position of the axially extending projection of the second cam means, said manually operated means including a second shaft extending coaxially with said support shaft and through one of said plates to receive said second cam means on its inner end, a knob on the outer end of said second shaft to permit manual rotation of the same, and a graduated scale carried by said frame to indicate the angular position of said second shaft thereby indicating the percentage of circuit on to circuit off conditions; the radial projection on said first cam means being effective to engage said operating member as said sliding assembly is driven in order to raise the operating member above said disk; and means for urging said sliding assembly along said support shaft toward the second cam means in order to seat the operating member on the periphery of said disk whenever the operating member is raised by said radially extending projection, thereby to establish one of said circuit conditions; the axial projections on said first and second cam means being engageable to force said sliding assembly axially away from said second cam means as said sliding assembly is driven, thereby to unseat the operating member from said disk and permit said biasing means to move the operating memer into engagement with the second cam means in order to establish the other of said circuit conditions.

7. The apparatus defined by claim 6 wherein said manually operated means includes a pawl mounted on said frame and a ratchet mounted on said second shaft for indexing said second cam means in its dilferent angular positions with respect to said first cam means.

8. A percentage timer for use in an electric circuit to control the proportionate time of circuit on and circuit off conditions during a particular operating cycle comprising a framework including a pair of interconnected spaced plates; driving means mounted on said framework; a first shaft on said framework; an electric switch carried by the framework for establishing the circuit on and off conditions; a switch operating member movable between different positions to open and close said switch; an axially slidable assembly mounted on and rotatable with said first shaft and driven by said driving means, said sliding assembly including a disk and a first cam means of generally circular shape but having a radius less than that of said disk, said first cam means including a first radially extending projection and a second axially extending projection; means biasing said switch operating m mber into engagement with the periphery of said first means; second cam means having an axially extending projection facing the axially extending projection of said first cam means; manually operated means for rotating said second cam means to adjust the position of the axially extending projection of the second cam means, said manually operated means including a second shaft extending coaxially with said first shaft and through one of said plates to receive second cam means on one end, a knob on the other end of said second shaft to permit manual rotation of the same, and a graduated scale carried by said framework and disposed adjacent said knob to indicate the percentage of circuit on to circuit off conditions; the radial projection on said first cam means being effective to engage said operating mem er as sliding assemblyis driven in order to raise the operating member above said disk; and means for urging said sliding assembly along said support shaft toward the second cam means in order to seat the operating member on the periphery of said disk whenever the operating member is raised by said radially extending projection, thereby to establish one of said circuit conditions; the axial projections on said first and second cam means being engageable to force said sliding assembly axially away from said second cam means as said sliding assembly is driven, thereby to unseat the operating member from said disk and permit said biasing means to move the operating member into engagement with the second cam means in order to establish the other of said circuit conditions.

9. The apparatus defined by claim 8 wherein said manually operated means includes a pawl carried by said framework and a ratchet carried by said second shaft for indexing said second cam means in its angular positions relative to said first cam means.

References Cited in the file of this patent V UNITED STATES FATE TS

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