US3672234A

US3672234A - Rapid-release escapement for timing programmers

Info

Publication number: US3672234A
Application number: US76894A
Authority: US
Inventors: Renato Gazzani
Original assignee: OMP OFF MECCANO PLAST
Current assignee: OMP OFF MECCANO PLAST; Omp Officine Meccanoplastiche Di Precisione Srl
Priority date: 1969-10-04
Filing date: 1970-09-30
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27
Also published as: NL7014504A; DE2048522A1; FR2064855A5; GB1305656A

Abstract

Reduction gearing driven by a motor drives a toothed transmission wheel. A toothed advancement wheel is driven by the toothed transmission wheel and is provided with an axial pin having a short longitudinal nib, and a long longitudinal nib located diametrically opposite to the short nib. An output wheel has two partial rings of teeth one of which is in driven alignment with the short nib and both of which are in driven alignment with the long nib. A dwell wheel is coaxial with and has a lost motion connection with the output wheel, and has a partial ring of teeth in driven alignment with the long nib.

Description

United States Patent Gazzani [151 3,672,234 51 June 27, 1972 [54] RAPID-RELEASE ESCAPEMENT FOR TIMING PROGRAMMERS [72] lnventor:

[73] Assignee:

Renato Gazzani, Frosinone, ltaly 0.M.P. Officine Meccanoplastiche Di Precislone S.R.L., Frosinone, Italy [22] Filed: Sept. 30, i970 [21] Appl.No.: 76,894

[56] References Cited UNITED STATES PATENTS 2,871,702 2/1959 Tetro ..74/112 X 3,319,477 5/1967 McVicker ..74/1 12 Primary ExaminerMilton Kaufman Attorney-Marshall & Yeasting ABSTRACT Reduction gearing driven by a motor drives a toothed trans- [30] Foreign Application Priority Data 4 mission wheel. A toothed advancement wheel is driven by the toothed transmission wheel and is provided with an axial pin Oct. 4, 1969 Italy ..40523 A/69 having a short longitudinal nib, and a g longitudinal nib located diametrically opposite to the short nib. An output [52] }J.S.(l ..74/3.5(2;,0 wheel has two partial rings of team one of which is in driven [51] 3 H alignment with the short nib and both of which are in driven [58] Field Search 7 alignment with the long nib. A dwell wheel is coaxial with and 200/38 38 38 33 3 A has a lost motion connection with the output wheel, and has a partial ring of teeth in driven alignment with the long nib.

' 6 Claims, 4 Drawing Figures 22 L I I 1 1 7 R a I I6 the cycle and then permits it to RAPID-RELEASE ESCAPEMENT FOR TIMING PROGRAMMERS BACKGROUND OF THE INVENTION This invention relates to an escapement for automatic timing programmers and, more particularly, to a rapid-release type of escapement in which the time interval between the pulses, that is to say between the step-by-step forward movements of the escapement itself, is not identical for every pulse. In particular, the interval of time relating to a given group of pulses can be any integral multiple of the time interval relating to another group of pulses. Furthermore, it is not necessary for the pulses belonging to oneor the other group to follow any specific order because. the order in which the pulses follow each other can be preset in any desired manner during the design stage.

In programmers equipped with an escapement according to the present invention it becomes possible to avoid double releases, a drawback that is common to all hitherto known rapid-release programmers, by means of a mechanical arrangementthat is not only certain in its action but also cheap.

The escapement according to the present invention also supplies the said programmer with an advancement system equipped with an extremely simple arrangement that automatically stops the advancement at any preselected point of v 7 continue after a fixed and preselected interval of time. I

1. Field of the Invention The escapement in question can find application also in equipment other than timingprogramme'rs but, by way of example that is not in any way to be considered limitative, it will here be described as applied to a programmer for automatic electric domestic appliances, such as washing machines, dish washers, and similar. In particular, the mechanism for the automatic stopping and restarting of the forward motion can find practical application in the most recent techniques of designing and constructing washing machines.

2. DESCRIPTION OF THE PRIOR ART The hitherto known automatic programmers have been equipped with escapements that produce a step-by-step advancement of the group of cams activating the electric circuits, these escapements being of two types:

a; Slow-release escapements. In these escapememse-during the phase of advancement-a lever or other mechanical means is guided by 'the same eccentric that supplies the forward motion or byother mechanical means. This arrangement prevents an accidental advancement of more than one step at a time and the consequent failure to respect the preselected program. As against this, systems of this kind require the drive means to be continually supplied with current throughout the phase of advancement, because the advancement is obtained by means of the addition of a costly supplementary circuit, in actual practice known as transit contact, or by means of artificial phase differences in the profiles of the eccentrics which reduce the machining tolerances and consequently entail a considerable increase of the cost.

b. Rapid-release escapements. In this type of escapement the above-mentioned drawbacks are eliminated thanks to the fact that the lever or other mechanical means of advancement is not braked during the advancement phase and can therefore descend freely. In this way, however, it becomes possible, particularly during the phases of the program when the eccentrics absorb a comparatively small mechanical torque, for example by virtue of the lack of variations in the profiles of the eccentrics themselves, for so-called oversteps to occur, that is to say the advancement will not consist of just a single step as desired and programmed, but rather of two or more steps; consequently there will be irregular operation and the preselected program will not be respected. Generally speaking, attempts have been made to solve this problem by devising braking systems that intervene whenever necessary, for example energy flywheels, feedback springs, etc., but these systems, quite apart from being costly, do not provide a certain and absolute guarantee against the possibility of an overstep.

Another drawback associated with programmers equipped with escapements constructed in accordance with hitherto known techniques is to be found in the fact that the designers of the machines, in designing the cycles, are rigidly bound to a series of pulses whose time intervals are constant and equal to each other, this being due to the fact that previous techniques were capable of offering differential pulses only by means of costly expedients; for example, the programmer could be equipped with two escapements or, as is the case with rapidrelease programmers, the programmer could be fitted with specific control cams, one for each program, to ensure an appropriate choice of the pulse duration.

One of the objects of the present invention is therefore to provide an escapement of the rapid-release type for timing programmers in which the possibility of an overstep occurring in the programmer is excluded in a sure and mechanically certain manner. This object is achieved without recourse to any supplementary mechanical means, but solely by means of an appropriate arrangement of the mechanical elements needed for the step-by-step advancement.

An advantageous characteristic of the present invention is to be found in the limited number of mechanical means that are required by the advancement system, in the low'cost of the said system, and in the fact that the system is operationally reliable for a long time owing to the complete absence of any parts whose action involves sliding friction.

Another object of the present invention is to provide an arrangement that will permit the step-by-step advancement to be stopped at any desired point of the cycle, the said stoppage being obtained in a simple, economic and mechanically certain manner, without the addition of any electrical control members and without the addition of any mechanical members that permit manual setting as in all hitherto known cases.

Another object of the present invention is to provide an escapement for automatic programmers in which the time interval between the pulses can be varied from one'pulse to another, the intervals themselves being capable of being preselected without any limitation or restraint other than the fact that each of the said time intervals must be an integral multiple of the duration that has been chosen for the basic pulse.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE INVENTION By referring to the drawings, it can be seen that the motor 11 is mounted outside the box that houses the movable pans of the mechanism; the output shaft of this motor is indicated byl 1a in FIG. 2.

, The motor 11 transmits its continuous rotatory motion through a reducing mechanism consisting of the three toothed wheels l2, l3 and 14 to a toothed transmission wheel 15 which can be clearly seen in FIG. 1 and which rotates about the shaft A.

The toothed transmission wheel 15 is then coupled with one or more cam wheels R for the operation of electric circuits the switching'of which is required not in an intermittent manner, but rather in a continuous one. The addition of such cam wheels is optional and does not form part of the present invention.

The shaft A on which the toothed transmission wheel 15 is mounted also carries .a second toothed wheel 16, this latter 26, all of which will be further I The second toothed wheel 16, rigidly fixed to the said first toothed wheel 15, has gear teeth only on a part of its circumference and transmits its motion to the toothed wheel 17 which, as will be described later, drives both the lower and the upper ring of teeth of the wheel which is provided with a double ring of teeth.

The toothed part of wheel 16 is capable of driving wheel'l7 through an arc of slightly more than 90. The toothed wheel 17, as can be seen in the view from below in FIG. 3 has on its lower side a double cam 18, that is to say a cam with two inversely symmetrical lobes.

As can be seen, each of the two lobes has one steep side and a more gently rising side. A wound spring 19 is mounted on a pin 20 fixed to the base of the housing of the escapement. One arm of the spring is held in position by the pin 21, this too being fixed to the base of the housing of the escapement, and the other arm presses against the profile of the double cam 18 of the toothed advancement wheel 17.

In this way the rest positions of the wheel 17 are the ones in which the arm of the spring 19 rests on the two lowest parts of the profile of the double cam 18 and, every time the toothed part of wheel 16 drives the wheel 17, the arm of the spring 19 will run along the profile of the double cam until it passes one of the two high points. The force of the spring will then bring the wheel back into the rest position displaced by 180 from the former rest position, and so on. In this way a rotation of the wheel 17 through 180 is obtained for every complete revolution of the wheel 16 whose circumference is partly toothed.

The toothed wheel 17 is provided with an axial pin 22 which carries two longitudinal nibs or noses placed diametrically opposite each other; more precisely, there is a short nib 23 which can engage only with the lower ring of teeth of the wheel 10 as well as a long nib 24 which is capable of becoming engaged with both the lower and the upper ring of teeth of wheel 10.

The wheel 16 has teeth only on a part of its circumference and the movement will therefore take place in the following manner:

The wheel 17 remains still for the whole of the period of time in which it is faced by the toothless part of the circumference of wheel 16. After a predetermined interval of time, however, the wheel 16 engages wheel 17 and begins to drive it. Wheel 17, in turn, will wind the wound spring 19 by means of the double cam; this winding will continue until the arm of the spring 19 passes beyond the upper dead point. At this point wheel 16 once again becomes disengaged from wheel 17, wheel 17 becomes idle, and the arm of the spring 19 returns to its former rest position. During this return phase the

nib

23 or 24 becomes engaged with one of the tooth spaces of the lower ring of teeth of the wheel 10 and drives it through an angle equal to the pitch of this lower ring of teeth.

The

nib

23 or 24, when in its rest position, remains engaged between two teeth of the lower ring of teeth of the wheel 10. This wheel 10, therefore is no longer free to rotate and will remain in this position until wheel 16 next becomes engaged with wheel 17 and the cam 18 becomes again displaced from its rest position.

Without any supplementary mechanical means, this arrangement therefore ensures in a mechanically certain manner that the wheel 10 with the two rings of teeth will not be able to move forward by more than one step at a time.

The pitch of the teeth in the lower ring of wheel 10 corresponds to the duration of the first group of pulses desired in this embodiment.

In view of the fact that the two

nibs

23 and 24 can act alternately' at intervals of 180 in the rotation of the toothed wheel 17, it can now be seen that the wheel 10 can be moved forward through desired increments that will be governed by the relative positions and the relationships between the teeth and the empty spaces of the upper and lower rings of teeth of the wheel 10. By way of example it should be noted that if one of the teeth on the lower ring of teeth is missing, the short nib 23 will turn idly and the wheel with two rings of teeth will obviously remain still for an interval of time that corresponds to the pitch of the lower ring of teeth.

Moreover, during the manual advancement of the cam block (not shown) for actuating electrical contacts, similar to the cam block R, which is attracted to the wheel 10, an operation that is generally required in practical applications of programmers for the purpose of starting the cycles and other maneuvers, the

nib

23 or 24 will be forced out of its rest position between two adjacent teeth of the wheel 10 but, every time the wheel 10 is moved forward manually through one complete pitch, it will return into the next rest position, being pushed there by the bias of the spring 19 on the double cam 18.

If this operation of manual advancement is carried out at a time when the

nibs

23 and 24 are not engaged with the teeth of wheel 10, then the stoppage of this wheel will be obtained by means of a conventional ratchet (not shown).

The wheel 10, to which said cam block (not shown) for actuating electrical contacts is attached, is the output member of the present device.

SUMMARlZlNG Since the nib 23 is shorter than the nib 24 and since, in the particular case that is being used as an example, the wheel 10 is provided with two rings of teeth of which we will suppose the upper one to have a pitch equal to the advancement it is desired to give to the cam block, while the other, the lower one, has either a tooth, or a group of teeth or several groups missing, we will have a situation in which the short nib 23 turns idly and without moving the wheel 10 in all positions in which the lower ring of teeth lacks a tooth; however, after the wheel 17 has rotated through the long nib 24 becomes engaged with the upper ring of teeth of the wheel 10 and will make it move forward by one tooth. After a further rotation through 180 of the wheel 17 the short nib 23 can again become engaged with the lower ring of teeth of the wheel 10.

Naturally, if there is a group of n teeth missing from the lower ring of teeth, n revolutions will be required before the lower nib 23 can again become engaged with this ring of teeth.

By varying the position and the number of the teeth in the upper ring of teeth of wheel 10, the position and the number of those pulses of the programmer cycle whose duration is determined by the long nib 24 can be varied.

We will now make reference to FIGS. 1 and 4 and describe the arrangement for stopping the, advancement in case one desires the wheel 10 with two rings of teeth to remain still for a prolonged interval of time, for example for such length of time as corresponds to the forward movement of the wheel by a certain number of teeth. It can be seen that the wheel 10 with two rings of teeth is provided with a fixed pin 25 which becomes engaged in a slot that has the form of a circular arc and is cut in a wheel 26 with a toothed sector 260 that corresponds exactly to the are occupied by the slot, the profile of the teeth of this sector being the same as that of the teeth in the upper ring of teeth of wheel 10.

The length of the slot in the form of a circular arc is such that the angle it s'ubtends at the center of the wheel corresponds to the number of teeth that defines the length of time during which one desires the wheel with two rings of teeth to remain still.

In normal conditions the pin 25 lies against the forward inner edge of the arc-shaped slot, that is to say the inner edge on the left of FIG. 4. The pin 25 will therefore drive the toothed wheel 26 and make it rotate.

in the position of the program in which one desires, in this particular case, to obtainthe stoppage of the forward movement the wheel 10 will lack a tooth both in its lower ring of teeth and in its upper ring of teeth.

The tooth of the upper ring of teeth will be missing precisely in the position corresponding to the pin 25. When the pin 25 finds itself in the position shown in FIG. 4, tooth 26b of the toothed sector 26a of wheel 26 comes in the same position as the missing tooth in the upper ring of teeth of the wheel 10. It is as well to specify that the part of wheel 26 that serves for this purpose is the one that finds itself between a and b. It should be noted that the angle of the slot is equal to the angle between the first tooth on the right and the missing tooth of wheel 26 (see a-b in FIG. 4).

At each subsequent revolution of the toothed wheel 17, the wheel which has a tooth missing from both rings of teeth will remain still as the missing teeth permit the

nibs

23 and 24 to pass during their rotation without engaging any teeth on the wheel 10 and, therefore, the pin 25 will also remain still; the toothed wheel 26, on the other hand, will during each rotation of the wheel 17 be engaged by the nib 24 and thus will move forward by one tooth, as indicated by the arrow, and we will therefore have a relative movement between the pin 25 and the slot of the toothed wheel 26. The step-by-step rotation of the toothed wheel 26 will continue until the backward inner edge of the slot, that is to say the inner edge shown on the right of FIG. 4, will come into contact with the pin 25 and will drive the wheel 10 forward by one step. In this way the longer nib 24 of the toothed wheel 17 will again be able to engage a tooth of the upper ring of teeth of wheel 10. However, since all the teeth of the toothed sector 26a have already been displaced from a to b, the longer nib 24 cannot drive the toothed wheel 26 which, moreover, is kept still by the ratchet 27, this ratchet being made of elastic material and pivoted to the housing of the escapement.

The toothed wheel 26 therefore remains still, but the wheel 10 with two rings of teeth continues to rotate by virtue of the action of the toothed wheel 17. As a result of the rotation of the wheel 10 the pin 25 will again become displaced inside the slot of the wheel 26 and will return to the position shown in FIG. 4, that is to say the normal position; it will thus come into contact with the forward inner edge of the slot and will begin to drive the wheel 26 forward again.

As hereinbefore stated, the

wheels

10 and 26 are idle, in that they are free to rotate about the shaft A, and they are driven only by the action of the

nibs

23 and 24. The wheel 26 functions, in the manner hereinbefore described, as part of the mechanism for controlling the intermittent rotation of the output member 10.

What I claim is:

l. A rapid-release escapement for imparting a variety of intermittent movements via an output wheel, comprising a motor, reduction gearing driven by the motor, a toothed transmission wheel which is driven by the reduction gearing, a toothed advancement wheel which is driven by the toothed transmission wheel and is provided with an axial pin having a short longitudinal nib, and a long longitudinal nib located diametrically opposite to the short nib, an output wheel having two partial rings of teeth one of which is in driven alignment with the short nib and both of which are in driven alignment with the long nib, and a dwell wheel which is coaxial with and has a lost motion connection with the output wheel, and which has a partial ring of teeth in driven alignment with the long nib.

2. A rapid-release escapement according to claim 1 wherein the toothed transmission wheel has only a partial ring of teeth, and wherein each rotation of the toothed transmission wheel drives the toothed advancement wheel through a half rotation.

3. A rapid-release escapement according to claim 2 wherein the toothed advancement wheel is provided with a cam having two parallel flat sides, and wherein a spring having a fixed mounting comprises a resilient leg which normally lies against a flat side of the cam, to urge the cam into one of two rest positions.

4. A rapid-release escapement according to claim 3 wherein in each rest position of the cam, one of the two nibs of the advancement wheel extends into a space between the teeth of at least one ring of teeth on the output wheel in order to prevent overstepping of the output wheel.

5. A rapid-release escapement according to claim 1 wherein the lost motion connection between the dwell wheel and the output wheel comprises a pm which is fixed to one of said wheels and which extends into an areuate slot in the other wheel, and wherein a partial ring of teeth on the dwell wheel subtends an angle equal to the angle of the arcuate slot.

6. A rapid-release escapement according to claim 5 com prising a ratchet which has a fixed mounting and which resiliently engages teeth on the dwell wheel.

i I i

Claims

1. A rapid-release escapement for imparting a variety of intermittent movements via an output wheel, comprising a motor, reduction geaRing driven by the motor, a toothed transmission wheel which is driven by the reduction gearing, a toothed advancement wheel which is driven by the toothed transmission wheel and is provided with an axial pin having a short longitudinal nib, and a long longitudinal nib located diametrically opposite to the short nib, an output wheel having two partial rings of teeth one of which is in driven alignment with the short nib and both of which are in driven alignment with the long nib, and a dwell wheel which is coaxial with and has a lost motion connection with the output wheel, and which has a partial ring of teeth in driven alignment with the long nib.

5. A rapid-release escapement according to claim 1 wherein the lost motion connection between the dwell wheel and the output wheel comprises a pin which is fixed to one of said wheels and which extends into an arcuate slot in the other wheel, and wherein a partial ring of teeth on the dwell wheel subtends an angle equal to the angle of the arcuate slot.

6. A rapid-release escapement according to claim 5 comprising a ratchet which has a fixed mounting and which resiliently engages teeth on the dwell wheel.