US3296390A - Time switch for controlling an electrical circuit of a process or apparatus for a preset period - Google Patents

Description

W. S'ALGER Jan. 3, 1967 3,296,39O I TIME SWITCH FOR CONTROLLING AN ELECTRICAL CIRCUIT OF A PROCESS OR APPARATUS FOR A PRESET PERIOD Filed July 9, 1964 3 Sheets-Sheet 1 R a Aw I I HH HHH Q N MQ Jan. 3, 1967 w. SALGER 3,296,390

TIME SWITCH FOR CONTROLLING AN ELECTRICAL CIRCUIT OF A PROCESS OR APPARATUS FOR A PRESET PERIOD Jan. 3, 1967 w. SALGER 3,296,390

TIME SWITCH FOR CONTROLLING AN ELECTRICAL CIRCUIT OF A PROCESS 0R APPARATUS FOR A PRESET PERIOD Filed July 9, 1964 5 Sheets-Sheet 5 United States Patent 3,296,390 TIME SWITCH FOR CONTROLLING AN ELEC- TRICAL CIRCUIT OF A PROCESS 0R APPA- RATUS FOR A PRESET PERIOD Werner Salger, Hamburg-Langenhorn, Germany, assignor to Lumoprint Zindler K.G., a corporation of Germany .Filed July 9, 1964, Ser. No. 381,310 Claims-priority, application Germany, July 19, 1963, L 45,402 7 Claims. (Cl. 20033) This invention relates to a time switch for controlling an electrical circuit of a process or apparatus for a preset period. Such timevswitches are useful, for eX- ample, in controlling the exposure time of photocopying apparatus.

Known time switches have a spring motor with an adjustable final stop; a large number of interlocking parts are needed for such mechanisms. It is also known to use an electric motor, the speed of rotation of which changes according to the voltage applied thereto. Such time switches are comparatively expensive and complicated to construct. A brake mechanism is in general needed in spring motors, in order to obtain equal lapses of time when the spring is released. The many interlocking parts have a certain backlash or play, which leads to inaccuracies. Moreover, these parts are of material which is temperatureor moisture-dependent, so that the adjustment is dependent on the changes in the weather.

The springs arranged in mechanical time switches must be of considerable size, in order to be able to record equally a series of time intervals to be apportioned.

Furthermore, known time switches are cumbersome and they often operate with considerable, substantially continuous noise. The starting of known time switches can, in certain instances, be dependent on the manner of movement of the release member, so that the starting point can vary according to the particular position of the release member.

It is therefore an object of the invention to provide a time switch which operates with precision, and which is constructed from few, easily produced parts. The switch should be not only maintenance-free and rugged in operation, but also, substantially independent of adjustment faults of the timer. It is intended to provide an industrial product which is substantially without need of adjustment and can be produced with the usual tolerances so that there can be clearance between the parts but provide a constant accuracy in operation.

The time switch according to the invention comprises a trackway constituted by a plurality of inclined surfaces arranged to permit a body to roll or slide down the surfaces successively, a switch for controlling an electrical circuit, a release mechanism arranged to simultaneously release the body at the upper end of the track and to open or close the switch, the switch being returned to its original state by the return of the body to its initial position after passage down the trackway, and the degree of overlap between at least two of the inclined surfaces being variable by relative movement of such surfaces, so as to alter the length of time taken between the release and return of the body.

The time period set can thus be adjusted by altering the length of the track.

The body is preferably rollable such as a spherical ball.

According to a preferred embodiment, a forked, bent carrier is provided for holding the ball in its starting position, and the carrier is attached to a pivoted lever connected to the switch. This lever can itself constitute the final portion of the trackway.

The trackway is preferably composed of two series of alternating bearing surfaces for the moving body each 3,2963% Patented Jan. 3, 1967 inclined slightly to the horizontal but the direction of inclination of one set being opposite to the other, one set being attached to one vertical wall of the apparatus and the other set being attached to another wall which is slidable with respect to the first set of surfaces upon movement of a time setting control.

The bearing surfaces are preferably arranged to constitute a generally rectilinear trackway for the ball. The surfaces are also preferably attached to their respective vertical walls at an angle inclined to the direction perpendicular to the vertical plane of the trackway, so that the ball travels between the surfaces and the opposite vertical walls. Thus, a track is simply provided and the accuracy of the time control is substantially independent of any faults in the adjustment of the apparatus.

The tolerances between the bearing surfaces and their respective opposite vertical walls are thus of no importance in view of the circular form of the rolling ball. Since the ball is in contact with the track at two points as it rolls, the friction is increased and this retards its travel and has the advantageous effect of increasing the time taken by the ball over the track, without lengthening the track. A corresponding effect can be obtained by channelling the track, although this increases the constructional costs.

The bearing surfaces are advantageously made from a material from which the ball springs on rebound, in order to absorb the kinetic energy of the fall of the ball from one surface to the next below and to ensure a definite small initial acceleration at each bearing surface.

The release mechanism preferably includes a springloaded plunger arranged so that movement of a starting lever tensions the spring, and the plunger is then released at a definite point of the movement of the lever, and projects the ball to the starting point of the trackway. It is advantageous to have the piston drawn by a snap spring action to a lateral bearing surface, in order to obtain a definite freeing independent of the position of the starting handle. The plunger is preferably mounted in an opening with enough freedom to permit some pivoting, and has an eccentric, elastic bufier attached to one side of the piston rod, to which it is diametrally opposed; the plunger also has a hook-like contact surface for engagement with the starting lever mechanism. This piston rod is thus held yieldingly in its normal position byits spring, but is pivotable from this position by pressure of the rear of the starting lever mechanism on its return. Thus the rear side of the hook-shaped contact surface is advantageously sloped in a direction such that the returning operating member deflects the piston about an eccentric buffer, in order to return to its starting position.

The invention will be illustrated in further detail by reference to a preferred embodiment thereof as shown in the accompanying drawings, in which:

FIGURE 1 is a side view of a time switch according to the invention, partly broken away and partly sectioned, showing the parts in the rest position;

FIGURE 2 is a section along the line 11-11 of FIGURE 1;

FIGURE 3 is a view similar to FIGURE 1 showing the parts in the position ready for release with the starting lever already substantially operated;

FIGURE 4 is a further view similar to FIGURE 1 showing the condition of the switch after release of the lever and during its operation, and

FIGURE 5 is a fragmentary section similar to that of FIGURE 2, to show an alternative constructional feature.

In all figures the same parts are designated by the same reference numerals.

Referring to FIGURES 1 and 2 it is seen that the time switch according to the invention is generally of flat construction, so as to be easily attached to a housing wall, such as that of a photocopier.

The apparatus comprises (FIGURE 2) an assembly 1, which contains a zig-zag track, and a cylindrical control assembly projecting therefrom and generally indicated by the numeral 2, and including a release arm 3 and a regulating member 4 for adjusting the length of time.

The assembly 1 comprises a flat box having a rear vertical wall 5 which can be attached, for instance, by screws to an apparatus to be controlled, and side walls 6, 7, 8 and 9. Within this box is formed a track for a falling ball, the tracking being partially constituted by bearing surfaces which are the upper surface of flanges 10, 11, 12 of nearly the same width as the side walls, and attached to the rear wall 5. These flanges (see FIG. 1) are approximately horizontal but inclined downwardly from left to right. Above these flanges is another flange 13, which has a downwardly directed portion 14 at its right-hand end as viewed in FIGURE 1. Further short flanges 22 and 23 are placed below the strip 14, separated by small gaps 31 and 32, and spaced well away from the ends of the strips 10, 11, 12. Towards the left-hand end of the flanges to 12 further vertical flanges 15 and 16 are arranged. The left-hand end of the upper most track defined by the flanges 13 and III is continuous with an arcuate but generally vertical track 19 defined by two walls 17, 18.

The box is partially covered in front by two sheets 24 and 25 which are attached to the adjacent side walls 6 and 7 in any suitable manner; these strips have inner edges 26, 27 which are cut away below (see FIG. 2); a sheet 28 covers the remainder of the track, and has edges which correspond with the profiles 26 and 27, and engage slidingly therewith. The sliding cover 28 is substantially parallel to the rear wall 5 and bears two further flanges 29 and 30, which project between the flanges It), 11, 12 and slope from right to left (in the opposite inclination to the slope of the flanges 1t), 11, 12), with their right-hand ends extending through the gaps 31 and 32 between the flanges 14, 22 and 22, 23; their left-hand ends are spaced well away from the walls 15, 16. A continuous path is thus made between the flanges 13, 10, 14, 29, 15, 11, 22, 30, 16, 12 and 23, 'as shown by the chain-dotted line 70.

Along the lower edge of the slide 28 is a toothed rack 33 in engagement with gear teeth 34 (FIG. 2) on a rotatable cylinder 35, having a manually actuable control portion 4 bearing time indices. A bush 36 (FIG. 2) is attached to the cover strip 25, and serves as carrier for the cylinder and the rest of the control assembly 2.

It will be seen that rotation of the control member 4 will cause, via the gears 33, 34, the cover 28 to slide upon the strips 24 and 25. The cover 28 is shown in FIGURE 1 in its extreme leftwards position; when it is moved toward the right the overlapping of the surfaces 10, 11, 12 with the surfaces 29 and 38 is reduced.

A ring 37 (FIGS. 1 and 2) is rotatably mounted in an annular recess upon the bush 36, and bears the release arm 3, constituted by a bar 38 and a handle 39. A tension spring 49 is stretched between the bar 38 and a boss 41 on the cover strip 25. The bush 36 preferably has a stepwise profile 42, so that a counterprofile thereof is provided which draws the step surface through the spring in reciprocal construction. The arm 38 is therefore normally held by the spring 40 in its initial position shown in FIG. 1, from which it is rotatable counterclockwise against the spring.

A curved lever 44 is pivotably mounted on a lug 43 on the ring 37; an arm 46 is mounted perpendicularly on the lever 44 (extending upwards from the plane of FIG. 1). In the cover strip 25 a slit is cut, which has a horizontal part 46 parallel to the side wall 7, and an upwardly inclined part 47. The arm projects through the slit 46, 47, and is movable along it if the ring 37 is turned by counterclopkwise movement of the release arm 4 38 attached to the ring. A parallel slit can be arranged in the back wall 5 to engage another arm 45, if desired.

From the lower side Wall 7 extends an abutment 48 having a hole 49 bored horizontally therethrough for the passage of a plunger 50; the hole 49 is large enough to permit the plunger to pivot somewhat in the hole. A quick-acting spring 52 mounted between the abutment 48 and an annular terminal stop 51 urges the spike-like tip 57 of the plunger towards the left. Upon the portion of the piston on the other side of the abutment 48 is mounted a sleeve 53 having an eccentric, preferably elastic buflcr 54, which contacts the abutment-48 under the action of the spring 52. The right-hand end of the plunger 50 engages the arm 45 with a hook-shaped portion 55, of an upward extent slightly more than half the width of the slit 46 and with an inclined terminal surface .59 (FIG. 4). Below the slit 46 a block 56 is fixed to the side wall 7, and has an upper surface positioned to guide the lower surface of the plunger 50 so that it cannot pivot downward and evade being acted on by the arm 45; the arm, however, is drawn away from the hook 55 when it enters the slit section 47. The block 56 thus ensures the precisely defined release point of the plunger 50, in conjunction with the positioning of the slit 46, 47.

Reference will now be made to FIGURE 3, which shows the position of the apparatus shortly before this point in time, when the plunger 50 has been moved towards the right and rests on the surface of the block 56, and the arm 45 is moving into the inclined slit portion 47 and so is nearly disengaged from the hook portion 55 of the plunger. A small further movement of the release arm 38 frees the plunger, which then strikes the ball 58 with its tip 57 under the action of the spring 52.

This position is shown in FIGURE 4. The arm 45 is here in the extreme right-hand end of the slit 47, while the upwardly directed portion 55 of the plunger is again in its initial position as shown in FIGURE 1, in which it is free from the surface of the block 56. When the arm 45 returns to its original position under the action of the spring 23, it can run over the inclined terminal surface 59 of the plunger, which is thereby deflected from its horizontal position due to the play in the opening 49 of the abutment until the arm 45 resumes its position of FIG. 1.

The final portion of the ball track is constituted by a lever 61) (FIG. 3), sloping to the left, and terminating in an angled ball holder 21 which rests on a ledge 20 when it contains the ball 58. The holder 21 is of forked construction, to enable the tip 57 of the plunger 50 to pass between the fork arms, which are squared off above and below, to strike the ball 58 (FIG. 3). Furthermore, between the fork arms is a rail 62 which leads into the side wall 17 of the trackway 19. This construction helps to guide the movement of the lever 61 correctly, and to retain the ball 58 within the trackway. If the entire apparatus is turned upside down, for example during transport, the ball 53 remains in the trackway.

The lever is mounted on a pivot plate pivotable-on a horizontal axis 61 (FIG. 3). Its shorter, right-hand end 63 moves the actuator arm of a micro-switch 64 (FIG. 3), connected to the circuit (not shown) to be controlled. This switch has a fixed contact arm 65, and an arm 66 which is movable by means of a snap-action spring 67 attached to the bent end of a further, pivotable actuator arm 68 with which the lever arm end 63 co-operates. In the position shown in FIG. 1 the arms 65 and 66 are separated. When the lever arm 60 is released from the weight of the ball 58 as in FIG. 4, the actuator arm 68 is able to move downwards and the spring 67 is disturbed so that it pushes the contact arm 66 upwardly to contact the arm 65. The spring 67 is so strong that it holds the lever 60 in the position shown in FIG. 1.

If the release arm 38 is moved counterclockwise from its position of FIG. 1 against the tension of the spring 23 into the position shown in FIG. .3, the spring 52 is compressed and further rotation of the arm results in the freeing of the plunger 50 as described above and shown in FIG. 4. The tip 57 of the piston strikes the ball 58 at a point below its largest diameter so that it is driven up the track 19. The lever arm 60 is then freed from the weight of the ball and its forked end rises as it pivots about its axis 61, the shorter end 63 of the lever 60 drops and causes the snap mechanism 67 to close the contacts 65 and 66 of the switch. A rebound surface 69 is arranged at the top of the track 19 where it reaches the top wall 13, which is so angled with respect to the track 19 that the rebounding ball is thrown to a definite position in the track. The ball then cascades along the path 70 (FIG. 1) until it again hits the arm 60 and rolls back into the holder 21; this causes the lever 60 to open the switch 64.

When the slide 28 is in the position shown in FIGURE 1 or 3, the ball 58 must roll along the entire length of the surfaces 10, 11, 12, 259 and 30. However, when the slide is pulled to the right, by turning the control 4 to another time setting, as shown in FIGURE 4, the ball only has to traverse shorter portions of the surfaces according to their degree of overlapping.

The surfaces of the flanges 10, 11, 12, 29, 30 along which the ball rolls are preferably not made of resilient material, thus, a comparatively rapid passage of the ball results. If the materials used are glass-hard, it is ensured that after the rebound of the ball from the next lower bearing surface a rebound vibration occurs which brakes the ball and gives a commencement of travel practically without kinetic energy. A preferred material for these surfaces is hardened polystyrene, and the ball 58 is preferably of steel.

Reference will now be made to FIGURE 5, which shows a preferred alternative method of arrangement of the horizontal bearing surfaces, exemplified by the surface 29. The flange 29 is attached to the slide 28 at an angle transverse to its long axis so that the ball 58 is held during its travel between this flange and the base 5. The surfaces -12 slope in the opposite direction. The surface 29 can hence be spaced away from the opposite side 5 by any clearance which is smaller than that of the diameter of the ball. Thus not only is a construction with large tolerances possible than those shown in FIG. 2, but also an increased friction is possible, which constantly retards the travel of the ball.

The length of the trackway along which the ball 58 passes, and hence the maximum time period for which the time switch can be set, can be increased by constructing the apparatus with either more or longer overlapping surfaces.

The apparatus of the invention has the notable feature, that the fall of the ball from one bearing surface to another can be audible, so that an estimate can be made from these successive sounds of the elapsed portion of the preset time period. The pitch of the noise of the fall of the ball is proportional to a constant time interval of the present time.

The time switch of the invention thus utilises a simple mechanism to produce a surprisingly precise time regulation. The apparatus takes up little spacepractically dependent on the diameter of the balland can easily be produced from castings.

As regards the previous expenditure on time switches, the invention presents a surprising solution, since a body following a path under its own weight takes a definite length path in an absolutely precisely defined time, and by means of particular measures it is ensured that the starting point of the path to be followed is reached very rapidly, the ball being practically brought to rest at the starting point.

I claim:

1. A time switch comprising, in combination, a housing, a vertically disposed trackway defined in said housing having a first end and a second end, said first end being disposed at a higher vertical position than said second end, a body rollable along said trackway under gravitational forces, a body holder movably mounted within said housing adjacent said trackway second end receiving said body from said second end and holding said body and movable between first and second positions, said holder normally assuming said first position and moving to said second position upon receiving said body, an electric switch connected to said holder and operated thereby upon said holder moving between said positions, and release means moving said body from said holder to said trackway first end whereby the time interval said holder is in said first position is sensed by said switch.

2. In a time switch as in claim 1 wherein said trackway consists of a plurality of elongated guide elements obliquely disposed to the horizontal, adjacent guide elements being arranged one vertically below the other and related whereby said body rolls from one element to the element immediately therebelow.

3. In a time switch as in claim 2 wherein adjacent guide elements are obliquely related in opposite directions to the horizontal, wherein said body traverses a zig-zag path moving through said trackway.

4. In a time switch as in claim 3, adjustable means supporting alternate guide elements upon said house permitting horizontal adjustment of said alternate guide elements with respect to the other elements whereby the length of the trackway path traversed by said body may be varied.

5. In a time switch as in claim 4, a scale mounted on said housing connected to said adjustable means supporting alternate guide elements, and indicia defined on said scale whereby said alternate guide elements may be preadjusted to define a predetermined trackway path length to be traversed by said body.

6. In a time switch as in claim 1 wherein said release means includes a plunger mounted within said housing for axial movement therein, a spring biasing said plunger toward a position in which said plunger engages said body upon said body being received by said holder, and actuating means connected to said plunger.

7. In a time switch as in claim 6, a lever pivotally mounted on said housing, a plunger abutment reciprocably mounted on said housing selectively engaging and operating said plunger to compress said spring, and means connecting said lever to said abutment whereby operation of said lever actuates said plunger.

References Cited by the Examiner UNITED STATES PATENTS 2,627,411 2/1953 Bartlam et a1. ZOO-61.11 X 2,855,203 10/1958 Hooker ZOO-61.11 X

BERNARD A. GILHEANY, Primary Examiner,

M. FLECK, Assistant Examiner.

Claims (1)

1. A TIME SWITCH COMPRISING, IN COMBINATION, A HOUSING, A VERTICALLY DISPOSED TRACKWAY DEFINED IN SAID HOUSING HAVING A FIRST END AND A SECOND END, SAID FIRST END BEING DISPOSED AT A HIGHER VERTICAL POSITION THAN SAID SECOND END, A BODY ROLLABLE ALONG SAID TRACKWAY UNDER GRAVITATIONAL FORCES, A BODY HOLDER MOVABLY MOUNTED WITHIN SAID HOUSING ADJACENT SAID TRACKWAY SECOND END RECEIVING SAID BODY FROM SAID SECOND END AND HOLDING SAID BODY AND MOVABLE BETWEEN FIRST AND SECOND POSITIONS, SAID HOLDER NORMALLY ASSUMING SAID FIRST POSITION AND MOVING TO SAID SECOND POSITION UPON RECEIVING SAID BODY, AN ELECTRIC SWITCH CONNECTED TO SAID HOLDER AND OPERATED THEREBY UPON SAID HOLDER MOVING BETWEEN SAID POSITIONS, AND RELEASE MEANS MOVING SAID BODY FROM SAID HOLDER TO SAID TRACKWAY FIRST END WHEREBY THE TIME INTERVAL SAID HOLDER IS IN SAID FIRST POSITION IS SENSED BY SAID SWITCH.

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