US2529480A - Timer - Google Patents

Description

Nov. 14, 1950 J. H. BOOTH 2,529,480

TIMER Original Filed Jan. 31, 1944 3 Sheets-Sheet l NOV. 14, 1950 I J, BOOTH 2,529,480

TIMER Original Filed Jan. 31, 1944 3 Sheets-Sheet 2 [ZYZ EUZEP z/ZMEJ H Boar-H- Nov. 14, 1950 Original Filed Jan. 31, 1944 J. H. BOOTH TIMER 3 Sheets-Sheet 3 z/AMH/z/ 5007/1 by LZ/Zm/ 1 722;);

Patented Nov. 14, 1950 TIMER James H. Booth, Detroit, Mich., assignor to Thompson Products, Inc., Cleveland, Ohio, a

corporation of Ohio Original application January 31, 1944, Serial No. 520,563. Divided and this applicationJune 8, 1946, Serial No. 675,454

15 Claims. (Cl. 200-30) This invention relates to a timer, and more particularly to a timer for a fuel injection system.

Many arrangements have been devised for metering and feeding fuel into the cylinders of an internal combustion engine. The most wide- 1y used form of combustion engine at the present time is one employing a carburetor for vaporizing and mixing the fuel with air to obtain a combustible mixture which in turn is fed to the engine cylinders. A type of system was devised some time ago which eliminated the need for a carburetor and is known as a fuel injection system.

In such a system, a metered quantity of liquid fuel under pressure is fed directly or through an intake manifold to each cylinder of the engine. Air is mixed with this metered quantity of fuel in the cylinder itself. This type of systern would have many advantages over the carburetor type of system if reliable and efiioient means is provided for metering and feeding the fuel into the cylinders.

One particular novel form of fuel injection system is described and claimed in my copending application entitled Fuel Injection System, U. S. Serial No. 520,563, filed January 31, 1944, and assigned to the same assignee as the present invention. The present application is a division of this aforesaid application, and is directed to the novel timer which is illustrated therein and which may be used efficiently in other types of fuel injection systems or the like.

One of the principal features and objects of the present invention is to provide a novel timer which is particularly suited for use in fuel injection systems.

Another object of the present invention is to provide a novel structure for opening and closing electrical circuits in timed sequence.

Still another object of the present invention is to provide a novel timer for internal combustion engines.

The novel features which I believe to be characteristic of my invention are set forth in particularity in the appended claims. My invention itself, however, both as to its manner of construction and method of control together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, in which:

Figure 1 is an elevational view of a timer embodying the novel teachings and principles of the present invention;

Figure 2 is a top enlarged view of the timer with the cover removed;

- Figure 3 is an elevational view partly in section of the interior of the timer as taken along' the line IIIIII of Figure 2;

Figure 4 is a sectional view of the timer as taken along the line IVIV of Figure 3;

Figure 5 is a bottom view of the top cylindrical housing member;

Figure 6 is a top plan view of the bottom cylindrical housing member;

Figure 7 is a top plan view of the slip ring and commutator block as viewed along the section line VIIVII of Figure 3;

Figure 8 is an isometric view of the switch block with certain portions thereof removed to show more clearly the movable arms mounted on the block;

Figure 9 is a sectional view of the switch block as taken along the line IXIX of Figure 2;

Figure 10 is a bottom plan view of the switch block showing the distributor contact fingers; and

Figure 11 is a circuit diagram illustrating a control circuit for a fuel injection system in which my timer may be used.

The timer mechanism I I illustrated in the various figures of the drawings is arranged to be driven through a bevel gear I2 in a manner hereinafter to be described. The timer is mounted in a pair of interlocking cylindrical housing mem bers I3 and I4, The upper end of the lower housing member I3 is provided with a radially out-l wardly opening channel I5, the upper lip I6 of which is cut away on diametrically opposite sides over a substantially arcuate portion as at IT and I8 (Figure 6).

The somewhat enlarged lower end Ma of the upper housing member I4 is provided with a radially inwardly opening channel 20, the lower wall or lip 2| of which is cut away on diametri cally opposite sides over a substantially arcuate portion as at 22 and 23, Fig. 5. The cut-away portions I! and I8, Fig. 6, and 22 and 23, Fig. 5,

are substantially coextensive to permit the lip 2| to be moved axially into the channel I5 and then the upper housing member I4 turned until the lip 2| is interlocked under the lip IS. The arcuate length of the lips I6 and 2| is sufiicientlyextensive that limited relative angular movement may be had between the housing members I3 and I4 without the lips becoming disengaged.

A timer shaft 24 extends up through the bottom of the housing I3 and is journaled in two bearing members 25 and 26, which are mounted 3|, and in the cylindrical surface of which are embedded a short arcuate-conducting segment 32 and a complete conducting ring 53. Conducting ring 33 includes an offset portion 3% directly opposite segment 32. I

symmetrically mounted in the lower housing I3 around the commutator 28 are eight brush assemblies 35, 36, 3'1, 38, 39, ll], t! and 42 (Figs. 3 and arranged in pairs (the number of pairs being the same as the number of engine cylin- 'ders). By way of illustration and not by way of;

limitation, a-- sufficient number of brush assemblies are illustrated in the drawings for operation with a four-cylinder engine, 7 7

Each brush assembly includes a brass sleeve 43, a carbon brushed, a spring 45 and a bolt 56, as is shown in Figure 3. The inner end of the sleeve 43 is threaded into an opening in the wall of the housing l3, while the outer end acts as a terminal post and is internally threaded near its outer end to receive bolt M5.

The upper brush assemblies 35, 3?, 39 and M of the respective pairs are located opposite the upper end of the cylindrical surface of the commutator 28, and; hence are disposed in the path of movement of the conducting segment 32 and the main body portion of conducting ring 33. The gaps between the ends of the conducting segment32 and the confronting portion of the ring 33- are'sufiiciently small that the brush 44 of each upper brush assembly will bridge the gap as the ring 33 moves out of engagement therewith, and as the conducting segment 32 moves into engagement therewith.

The lower brush assemblies 36, 38, 5E) and 42 are located in the path of movement of the offset portion 34 of the conducting ring 33. This ofiset portion 3 3 is arranged to be engaged 5110- cessively and at spaced intervals by first one lower brush assembly and then another, and this period of engagement will coincide with the engagement of the conducting segment 32 by the upper brush assembly of the sam pair.

The timer H is also provided with a pair'of cam-operated switches 41 and 48, the former being a normally closed switch and the latter being a normally opened switch. These two switches are mounted on a plate 59 which is generally circular in shape but which is provided with two portions 50, 51 which project slightly as shown in Figures 4, 8 and 10. Plate 49 is seated on the upper end ofthe housing 13. The lower interior portion of the housing I4 is recessed to provide an annular shoulder 52 which is eccentrically disposed with respect to the central axis of the housings l5 and Id. The inner diameter of the annular shoulder 52 is substantially the same or slightly greater than the distance across the disk 49 where the lips 50 and 5i are located. The inner wall defined by the shoulder 52 is indicated at 52a, Figs. 3 and 4.

The disk 49 is prevented from rotating by providing a pair of ribs 53 and 54 on the undersurface thereof which fit into channels 55 and 55 formed in the upper edge 5'! of the lower housing 13. The disk 49 is also provided with an oblong center opening 58 through which the shaft 24 extends. The major axis of the oblong center opening 58 is parallel to the ribs 53 and 5 3.

Due to the eccentricity of the shoulder 52 and duevto the fact that the lips 50and 5| of the disk 49 lie against this shoulder 52, it will be apparent that limited movement of the disk 49 may be had with respect to the shaft 25, it being remembered that the ribs 53 and 54 in conjunction with the channels 55 and 56 confine the movement of the disk 19 to a single path.

The two cam-operated switches i! and 48 which are mounted on the disk Q9 will now be described. As previously mentioned, the switch ill is a normally closed. switch and includes a movable contact arm 59 which is mounted for limited movement on a pin 65. The outer free end of the movable contact arm includes a contact button 5i and the intermediate portion of-the arm 55 includes contact button 52 substantially opposite the opening 58 in the disk 49. Substantially opposite the opening 58 in the disk 39 is secured a raised portion or button 62 of fiber or other insulating material which provides a cam follower. A second movable contact arm 63 is mounted on the same pin above the movable contact arm 59. This second movable contact arm 63 is somewhat shorter than the movable contact arm 59 and is provided with a contact button on the side of the arm away from the hole 58 on the disk d9. This movable arm'63 does, however, have a raised portion or button 65 which is similar to the raised portion 62 on the arm 59.

Since the movable contact arm 53 must be electrically insulated from the movable contact arm 59, an insulating bushing 55 is provided around the shank of the pin 65 of the opening 61 through which the pin-s5 passes (see Figure 9). Insulating washers 58 and 59 are also provided on opposite ends of the bushing 66 to complete the insulation of the arm 63 from the pin 60.

A third movable contact arm ii! is mounted on a second pin or post 1| behind the movable contact arm 63. It is to be understood that this movable contact arm "it! lies in the same plane of movement as the" plane of movement of the contact arm 53, and is provided with a contact button 12 (Fig. 2) which is arranged to be engaged by the contact button 6 1 on the arm 53.

A stationary block 13 (Fig. 2). is mounted on the disk 49 on the opposite side of the hole 55 fromthe pin or post 50. The block '53 carries two adjustable stop members M and 15 which are provided, respectively, with lock nuts l5 and ii. It is also provided with an adjustable stationary contact '58 having a threaded shank 19 which extends through the block 13 and which is provided on the underside of the block it with a lock nut 88. Stationary contact 78 is arranged to be engaged by the contact button El (Fig. 8) on the movable contact arm 59. The adjustable stop M limits the. clockwise movement of the movable contact arm 63 about the pin or post 60. The adjustable stop 15 is arranged to be engaged by the projecting or bent tip portion 8! of the movable contact arm 18, and is thus arranged to limit the clockwise movement of the movable contact arm 10 about the post 1 I.

Each of the arms 59 and 63 is provided with a tail portion 82 and 83 (Fig. 8), respectively,

4 which are engaged by a leaf spring 84 (Fig. 2)

mounted on a post 85 and have a pair of fingers 86 and 81 (Fig. 9) which extend around a fixed post 88 and engage the tail portions 82 and 83, respectively, of the movable arms 59 and 63. These leaf spring portions 86 and 81 tend to move the arms 59 and 63 in a clockwise direction about their posts 60, and it will thus be understood that these arms are normally biased against the stationary contact I8 and the adjustable stop I4, respectively.

A leaf spring 89 (Fig. 2) is rigidly mounted on the post 90 and is sprung in such a manner as to normally urge the movable contact arm 10 against the adjustable stop 15.

The adjustable stops I4 and are so adjusted with respect to each other that the contact button 64 and the movable contact arm 63 is out of engagement with the contact button '12 on the movable contact arm 10. A relatively slight movement of the contact arm 63 in a counter-clockwise direction, however, will cause it to engage the movable contact arm 10 and this engagement will continue even though further movement of the movable contact arm 63 follows.

It will thus be understood that the contact arm 10 is in effect merely a yieldable stationary contact.

Two cam disks 89 and 89a (Fig. 11) are rigidly secured to the shaft 24 in any suitable manner. Cam disk 89 has four raised portions 9|, 92, 93 and 94 (see Figure 11). Cam disk 89a has four raised portions similar to those of cam disk 89 and which are identified as 95, 96, 91 and 98 (see Figures 2 and 11) The projecting portions 9I to 94 on cam disk 89 are arranged to engage the cam follower 62 on the movable contact arm 59 and lift the latter off stationary contact 18 each time one of the projections 9| to 94 engages the cam follower. The raised portions 95 to 98 on the cam disk 90 are arranged to engage the cam follower 65 on the movable contact arm 63. Each time that one of the raised portions 95 to 98 engages the cam follower 65, the movable contact arm 83 is moved to cause engagement of the same with the contact arm I0.

It will, of course, be understood that the number of raised portions on the cam disk 89 as well as the number of raised portions on the cam disk 89a is such as to correspond to the number of cylinders of the internal combustion engine with which the timer is associated.

It will be apparent from the above description that the length of time that the normally closed switch 41 remains open and the length of time that the normally open switch 48 remains closed depends upon the shape of the projecting portions on the respective cam disks 89 and 90 and on the speed of rotation of the timer shaft 24.

It will further be apparent that this length of time may be adjusted slightly by varying the relative positionof the switch block 49 with respect to the shaft 24, since this varies the effectiveness of the projecting portions on the cam disks 89 and 90, and in effect, varies the angular extent on the cam disks over which one of the movable contact arms has been lifted away from its normal position.

As will be evident from Figure 4, rotation of the upper housing member I4 by means of the arm I05, causes the portion of the wall formed by the shoulder 52 to shift relative to the extended portions 50 and SI of the member 49. One or the other of these portions then engages the wall 52a and causes the member 49 to shift along the axis determined by the ribs 53 and 54, thereby shifting the switches 4'! and 48, Figure 8, relative to the shaft 24 and the cams 89 and 89a. This movement varies the dwell of the cam followers 62 and 65 on the cams 89 and 89a and thus controls the duration of the period during which the solenoid I24 is energized to inject fuel to each cylinder of the engine. The measured quantity of fuel admitted on each cycle is thereby controlled and the speed of the engine adjusted.

A pair of contactor brushes 99 and I00 (Figs. 9 and 10) for continuous sliding engagement with the conducting rings 30 and 3| (Fig. 7), respectively, on the upper surface of the commutator block 28 are conveniently mounted on the ribs 53 and 54, respectively, of the switch block 49.

The upper end of the housing I4 is preferably closed off by a cover plate I03 which is screwed to the upper end of the housing I4 by a suitable bolt I04.

Any mechanical means may be provided for varying the angular position of the upper housing member I4 with respect to the lower housing member I 3 to thereby vary the eccentricity of the switch plate 49 with respect to the shaft 24. For purposes of illustration, a lever arm I05 has been shown in Figure 3 as the means by which the upper housing member I4 is angularly moved about its vertical axis with respect to the lower housing member I3.

In the foregoin paragraphs, I have described one embodiment of my novel timer. In order that the distinctive features and characteristics of this invention may be more readily appreciated and in order that the operation of this timer may be more clearly described, I have illustrated in Figure 11 a fuel injection system control circuit in which the timer may be used, and which control circuit is described and claimed in my aforementioned copending application, Serial No. 520,563.

As shown in Figure 11 of the drawings, the commutator ring 33 has been developed so as to show all of the brush assemblies 35 to 42. For the purposes of this application, it is sufficient to say that each cylinder of the internal combustion engine with which the present timer II is associated is provided with two valve operating solenoids I24 and I25 and the pairs of solenoids I24 and l 25 for each cylinder have been identified diagrammatically with the letters A, B, C, and D, each letter designating a different cylinder. It is desired that the timer II effect the energization and deenergization of each solenoid I24 and I25 of each cylinder A, B, C, and D in a certain desired sequence as will hereinafter be pointed out.

Energy for operating the various solenoids I24 and I25 is obtained from any suitable source of electro-motive force, such, for example, as a sixvolt battery I05. The negative side of the battery I06 is grounded as at E0], while the positive side of the battery is connected through a conductor I08 to the commutator ring 33. The particular manner in which the conductor I08 is connected to the commutator ring 33 is to connect the conductor I to brush 99 (Figs. 9 and 10) which, in turn, engages the conducting ring 30 (Fig. '7). This ring 30 is connected to the interior of the block 29 to the commutator ring 33. The positive side of the battery I06 is also connected through the conductor I 08 and a branch conductor I09 to the movable contact arm 59 of the switch 41.

The upper brush assemblies 35, 31, 39 and H are connected through conductors II 0, III, H2, and H3 to the upper valve assembly coils I25 of a-szaeso cylinders A, B, C, and D, respectively. Similarly, the lower brush assemblies 36, 38, 40 and @2 are connected through conductors H4, H5, IIS and I ll, respectively, to the lower valve assembly coils I24 of the cylinders A, B, C, and D, respectively. The stationary contact '58 of the switch a1 is connected to the conducting segment 32 through the conductor I IS. The contact arm ill of the switch 48 is grounded through a conductor H9. The movable contact arm 53 of the switch G8 is connected through a conductor I25 and a common bus I2! to the other end of each of the lower valve assembly coils IZG of the cylinders A, B, C, and D, respectively. The ends of the upper valve assembly coils I25 which are not connected to the brush assemblies 35, 31, 39 and All are connected together by a, common bus I22, which, in turn, is grounded as at I23.

Without describing the details of the valve mechanism of the fuel injection system, it will be sufficient to say that the coils IZd are energized to cause the fuel injection valve to open and admit fuel, and the coils I25 are energized to cause the valve to close. With this understanding, it' will be apparent that the fuel injection valves of each cylinder are opened and closed during the time that the oif-set portion 34 of the commutator ring 33 and the conducting segment 32 are in engagement with one of the pairs of brush assemblies 35 to 42. Which cylinder is having its fuel injection valve opening solenoid L25 energized will depend upon which pair of brush assemblies 35 to A2 is in engagement with the oif-set portion 3A and the conducting segment 32 at the time.

Let it be assumed, for example, that the conducting ring 33 is being moved in the direction indicated by the arrow in Figure 11. As shown by the full line in Figure 11, all of the upper contacting brushes 35, Si, 39 and ii are in engage ment with the main body portion of the commutator ring 33. Under such a circumstance, all of the upper valve assembly coils I25 of the cylinders A, B, C, and D are energized.

Furthermore, since none of the lower contacting brushes 36, 38, 48 and :32 are in engagement with the offset portion at of the commutator ring 33, it is apparent that the lower valve assembly coils I2 1 of the cylinders A, B, C, and D are all deenergized. Hence, in the position shown by the full line in Figure 11, all of the fuel injection valves with which the operating coils I2 1 and I25 are associated are closed.

As the rotation of the disk 29 continues, it carries the commutator ring 33 in the direction indicated by the arrow, the brushes Q and 39 will ride onto the off-set portion a l and the conducting segment 32, respectively. This now places the engine cylinder with which the brush assemblies 39 and All are associated under control of the cam-operated switches ti and A8. The valve actuating solenoids I24 of the remaining cylinders A, B, and D are still deenergized, however, and hence their associated valves remain closed.

Due to the fact that the brush ill is now in engagement with the off-set portion 3 1, it will be apparent that the lower coil I2 3 of the cylinder C will be energized through the cam-operated switch 48 as soon as the movable contact arm 5-3 thereof is moved into engagement with the yieldable contact arm III. The electrical circuit for this energization circuit extends from the battery I06 through the conductor I98, commutator ring 33, brush 40, conductor IIG, coil [2d of cylinder C, conductor I2I, conductor I20, movable contact 8 arm 63, yieldable contact arm Ill and conductor I I9 to ground.

*The energization of the upper valve assembly coil I25 of cylinder C is under control of the camoperated switch M. This coil I25 of cylinder C remains energized only so long as the movable contact arm 59 of the switch ll remains in engagement with the stationary contact '58. The reason for this is that the energization of the upper valve assembly coil I25 of the cylinder C is transferred from the commutator ring 33 and is now made through the switch All and the conducting segment 32.

More particularly, the coil I 25 of cylinder C remains energized while the switch M is closed through conductors IE8 and I59, switch d'l, conductor I I8, conducting segment 32, brush 39, conductor H2, coil I25 of cylinder C, and conductor E22 to ground I23. As soon as the movable contact arm 59 is lifted off of the stationary contact l8, however, this energization circuit is broken and the upper valve assembly coil Hi5 of cylinder C becomes deenergized.

In the embodiment of the invention above described, the movable contact arm 53 is arranged to close simultaneously with the opening of the movable contact arm 59. Likewise, the movable contact arm 59 is arranged to open simultaneously with the closing of the movable contact arm 53. The length of time which the movable contact arm 63 remains closed. and the movable contact arm 5Q remains open determines the length of time which the fuel injection valve of the cylinder remains open.

As the disk 29 continues to rotate, the off-set portion 3 and the conducting segment -52 will successively engage the brushes 42 and M, then the brushes 36 and 35, and finally the brushes 3% and 31, which completes one revolution of the disk 29. The length of time that each intake valve remains open will, of course, be determined by the relative position of the upper housing member 54 of the timer M with respect to the lower housing member I3 as determined by the actuating lever I05.

While not shown, it will be readily apparent to all those familiar with a fuel injection system that a variable air intake opening is provided for the intake manifold of the engine, and this opening may be varied in size by any conventional mechanism operated in conjunction with the operating lever H15 of the timer.

While I have shown a particular embodiment of my invention, it will, of course, be understood that I do not wish to be limited thereto, since many modifications may be made, and I, therefore, contemplate by the appended claims, to cover all such modifications that fall within the true spirit and scope of my invention.

I claim as my invention:

1. A timer comprising a pair of contiguous interlocking cylindrical members forming a housing, a timer shaft extending through and journaled in an end wall of one of said housing members, a plate member in said housing transversely of said shaft, said plate member having an opening substantially larger than said shaft through which said shaft extends, said plate member being adjustably mounted for limited movement over a single path lying in a plane substantially perpendicular to said shaft, a plurality of switches mounted on said plate member including a normally closed switch and a normally opened switch, and a pluralit of cams on said shaft for cyclically operating said switches.

2. A timer comprising a pair of contiguous interlocking members forming a housing, a timer shaft extending through and journaled in an end wall of one of said housing members, a plate member in said housing transversely of said shaft, said plate member having an openin substantially larger than said shaft through which said shaft extends, said plate member being adjustably mounted for limited movement over a single path lying in a plane substantially perpendicular to said shaft, a normally closed switch and a normally opened switch mounted on said plate member, a cam disk for each of said switches secured to said shaft, one of said disks having means for periodically opening said normally closed switch, and the other of said disks having means for periodically closing said normally opened switch.

3. A timer comprising a pair of contiguous interlocking cylindrical members forming a housing, a timer shaft extending through and journaled in an end wall of one Of said housing members, a plate member in said housing transversely of said shaft, said plate member having an opening substantially larger than said shaft through which said shaft extends, said plate member being adjustably mounted for limited movement over a single path lying in a plane H substantially perpendicular to said shaft, a pair of movable switch arms mounted above the other for movement in spaced parallel planes, a stationary contact on said plate arranged to be engaged by one of said movable arms, a yieldable contact arm arranged to be engaged by the other of said movable arms, means for urging said movable arms and said yieldable arm toward said timer shaft, said stationary contact acting as a stop member for its associated movable contact arm, additional stop means for said other movable arm and said yieldable arm, said stop means for said yieldable arm being arranged to normally maintain said yieldable arm and said second movable arm separated, radially projecting means on said shaft in the plane of said first movable arm, radially projecting means on said shaft in the plane of said second movable arm, said radially projecting means being arranged to periodically separate said first movable contact from its associated stationary contact and for closing said second movable contact against said yieldable contact.

4. A timer comprising a pair of contiguous interlocking cylindrical members forming a housing, a timer shaft extending through and journaled in an end wall of one of said housing members, a plate member in said housing transversely of said shaft, said plate member having an opening substantially larger than said shaft through which said shaft extends, said plate member being 'adjustably mounted for limited movement over a single path lying in a plane substantially perpendicular to said shaft, a pair of movable switch arms mounted above the other for movement in spaced parallel planes, a stationary contact on said plate arranged to be engaged by one of said movable arms, a yieldable contact arm arranged to be engaged by the other of said movable arms, means for urging said movable arms and said yieldable arm toward said timer shaft, said stationary contact acting as a stop member for its associated movable contact arm, additional stop means for said other movable arm and said yieldable arm, said stop means 10 for said yieldable arm being arranged to normally maintain said yieldable arm and'said second movable arm separated, radially projecting means on said shaft in the plane of said first movable arm, radially projecting means on said shaft in the plane of said second movable arm, said radially projecting means being arranged to periodically separate said first movable contact from its associated stationary contact and for 3 closing said second movable contact against said yieldable contact, and means responsive to a relative rotational movement between said cylindrical members for shifting the position of said plate member with respect to said shaft.

5. A timer comprising a pair of contiguous interlocking cylindrical members forming a housing,a timer shaft extending into said housing through one end thereof, a switch mounting plate seated against the inner end of one of said members, said plate having projecting arcuate lips, the other of said members having an eccentrically formed inwardly facing annular shoulder against which said lips are seated, and means for preventing relative rotation of said plate whereby rotational movement of one cylindrical member with respect to the other causes movement of said plate member toward and away from said shaft.

6. A timer comprising a housing, a timer shaft extending into said housing, a plate member in said housing disposed transversely of said shaft, said plate member having an opening substantially larger than said shaft through which said shaft extends, said plate member being adjustably mounted for limited movement crosswise of said shaft, a plurality of switches mounted on said plate member including a normally closed switch and a normally opened switch, and a plurality of cams on said shaft in proximity to said switches for cyclically operating said switches.

7. A timer comprising a housing, a timer shaft extending into said housing, a-plate member in said housing disposed transversely of said shaft, said plate member having an opening substantially larger than said shaft through which said shaft extends, said plate member being adjustably mounted for limited movement crosswise of said shaft, a normally closed switch and a normally open switch mounted on said plate member, and at least one cam for each switch on said shaft for cyclically moving its associated switch away from its normal position.

8. A timer comprising a housing, a timer shaft extending into said housing, a plate member, in

said housing disposed transversely of said shaft,

said plate member having an opening substantially larger than said shaft through which said shaft extends, said plate member being adjustably mounted for limited movement crosswise of said shaft, a plurality oi switches mounted on said plate member including a normally closed switch and 'a normally opened switch, a plurality of cams on said shaft in proximity to said switches for cyclically operating said switches and means for moving said plate member to vary the position of said switches with respect to said cams.

9. A timer comprising a housing, a timer shaft extending into said housing, a plate member in said housing disposed transversely of said shaft, said plate member having an opening substantially larger than said shaft through which said shaft extends, said plate member being adjustably mounted for limited movement crosswise of said shaft, a norm-ally closed switch and a normally open switch mounted on said plate member, at least one cam for each switch on said shaft for cyclically moving its associated switch away from its normal position, and means for adjustably moving said plate member thereby to vary the relative spacing between said cams and their associated switches.

10. A timer comprising a housing, a timer shaft extending into said housing, a switch supporting member mounted in said housing for limited back and forth movement in the transverse plane of said shaft and diametrically of said shaft, a plurality of switches on said member including a normally closed switch and a normally opened switch, and a plurality of cams on said shaft in proximity to said switches for cyclically operating said switches.

11. A timer comprising a housing, a timer shaft extending into said housing, a switch supporting member mounted in said housing for limited movement crosswise of said shaft, a normally open switch mounted on said member, a normally closed switch mounted on said member, said switches being spaced axially of each other with respect to said shaft, and a plurality of cams on said shaft in proximity to said switches for "cyclically operating said switches.

12.v A timer comprising .a housing, a timer shaft extending into said housing, a switch supporting member mounted in said housing for limited movement crosswise of said shaft, a normally open switch and a normally closed switch mounted on said member, said switches being spaced from each other in an axial direction with respect to said shaft, and a'pair of cam rings on said shaft lying respectively in the planes of said switches and in engagement with said switches, said cam rings including a plurality of radially outwardly projecting humps for cyclically moving said switches away from their respective normal positions.

13. A timer comprising a housing, a timer shaft extending into said housing, a switch supporting member mounted in said housing for limited movement crosswise of said shaft, a normally open switch and a normally closed switch mounted on said member, said switches being spaced from each other in an axial direction with respect to said shaft, a pair of cam rings on said shaft lying respectively in the planes of said switches and in engagement with said switches, said cam rings including a plurality of radially outwardly projecting humps for cyclically moving said switches away from their re- 12 spective normal positions, and means for moving said member to vary the spacing between said cam rings and said switches, thereby to vary the time said switches are held away from their respective normal positions by said cam ring humps.

14. A timer comprising a housing, a rotatable timer shaft extending into said housing, a switch supporting member mounted in said housing, a. pair of switches mounted for movement toward and away from said shaft in spaced parallel transverse planes of said shaft and each having an inner and an outer position, means normally biasing said switches to their respective inner positions, and a pair of cam rings on said shaft in the planes of said switches respectively, said cam rings having projecting cam portions thereon for moving said switches from their inner to their outer positions each time.

said cam portions strike said switches.

15. A timer comprising a housing, a rotatable timer shaft extending into said housing, a switch supporting member mounted in said housing for movement crosswise of said shaft along a single path, a pair of switches mounted for movement at substantially right angles to the path of movement of said spporting member toward and away from said shaft, said switches lying in spaced parallel transverse planes of said shaft, and each having an inner and an outer position, means normally biasing said switches to their respective inner positions, one of said switches being normally closed in its inner position and the other of said switches being normally open in its inner position, a pair of cam rings on said shaft in the planes of said switches respectively, said cam rings having projecting cam portions thereon for moving said switches from their inner to their outer positions each time said cam portions strike said switches, and means for adjustably moving said switch supporting member, thereby to vary the length of time said switches are held in their outer positions by said cam .portions.

JAMES H. BOOTH.

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

UNITED STATES PATENTS Number Name Date 1,869,814.. Karkau Aug. 2,. 1932

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