US 2222217 A
Description (OCR text may contain errors)
Nov. 199 1940. c. A. soLrNsKs ESCAPEMENT MECHANISM Filed Dec. 30, 1959 M65 A QQ/1m BY /M// 75 ATTORN Y.
Patented Nov. 19, 1940 UNITED STATES ESCAPEMENT MECHAN ISM Charles A. Solinski, Chicago, Ill., assigner to The Exhibit SupplyCompany, Chicago, Ill., a, corporation of Illinois Application December 30, 1939, Serial No. 311,732
This invention relates to mechanical movements and has as its principal object the provision of an improved escapement of general application and especially suited for actuation by an electromagnet in a stepping switch assembly.
Viewed in its more detailed aspects, the invention provides an escapement of the rocking type with opposite pawls adapted to engage the ratchet teeth on a ratchet disc or member, one of the pawls being movable relative to the other and the` entire escapement being pivoted so that as one of the pawls is withdrawn, the other is urged into position to block movement of the ratchet member after displacement of the latter the distance of one or `some other predetermined number of teeth.
A further object is the provision of an improved escapement capable of rapid actuation and positively accurate operation and one which cannot be injured by faulty alignment or operation of the associated parts.
A further object is the provision of an escapement including pawls spaced on opposite sides of a pivot `for rocking movement as a 'unit into and outof stopping engagement with the teeth on a ratchet disc, one of the pawls being movably mounted on the other and being urged by spring means `into a normal position against a stop carried on said other member and being so disposed that when the escapement is rocked from normal position the normally disengaged pawl will be disposed in operative relationship with the teeth of the ratchet member prior to disengagement of the other pawl, the relatively 35 movable pawl yielding upon engagement with the ratchet teeth responsive to continued rocking of the escapement to withdraw the main pawl.
Other objects, advantages and novel aspects of the invention reside in certain details of construction as well as the cooperative relationship of the component parts of the illustrative embodiment described hereinafter in view of the annexed drawing, in which:
Fig. l is an elevational View of a stepping switch employing a step by step take-off which utilizes the novel escapement mechanism;
Fig. 2 is a section through the escapernent mechanism along lines 2-2 of Fig. 1;
Fig. 3 is a fragmentary perspective `of the escapernent and ratchet disc.
For purposes of illustration, the escapement has been shown in conjunction with a stepping switch including a ratchet disc I0 carried on a stud I I to rotate on a mounting plate l2: Spring means I3 is disposed between the disc and plate to urge the :disc in a clockwise direction into a normal position in which a switch operating pin I4 will engage the arm I5l of a switch to open the same.
The ratchet disc is intended tobe stepped away from its normal position by a pawl I6 which is reciprocated by a member il attached to: the armature I8 of a solenoid I9.
In order to hold the ratchet disc against retrograde movement, there is provided the improved escapement mechanism generally indicated at 2) and including, as shown in Figs. 2 and 3, a first or main escapement lever 2l pivoted as at 22 upon a bracket 23 (Fig. 2) secured to the main mounting plate. This lever is provided with, and constitutes a part of, a pawl 2t shaped to engage the sharply pitched teeth 25 of the ratchet disc. At its end opposite the pawl, the lever is provided with a lug 26 to which is attached a normal spring 2l urging the pawl into operative en-` gagement with the teeth of the disc.
The escapement is completed by the provision of a second escapement lever 2li pivotally mounted as at 280, upon the first lever and having a pawl 29 at its end opposite the pivotal mounting thereof and opposite the first pawl 2t.
The second pawl lever is provided between its ends with a lug 30 to which is attached one end of a normal spring 3| which is secured at its remaining free end to the lug 26 on the first pawl lever.` The spring 3l is relatively light in the embodiment shown, and urges the second pawl into a normal position toward the ratchet disc, there being an upturned stopping ear 32 struck up from the first lever to limit the movement of the second pawl in its normal position.
In the illustrative embodiment, the entire escapement, consisting of the two pawl levers, is intended to be rocked from the normal position of Fig. l by operation of a take-off solenoid 33 pivotally linked with the escapement by means of a pin 34 on the main or first escapement lever and which projects into a slot 35 in the armature 36 of this solenoid.
In the operation of the escapement, and assuming that the solenoid I9 has been previously actuated a number of times to step the disc away from its normal position to an advanced position, action of the spring 2l', urging the main pawl to project the pawl portion 24 thereof in between certain teeth on the ratchet dise, will prevent the movement of the latter back to normal position. When it is desired to restore the disc in steps toward normal position, solenoid 33 is energized to attract plunger 36, and in consequence rock the entire escapement in a clockwise direction, so that pawl 24 is withdrawn from its normal holding engagement with the teeth of the disc while pawl 29 is moved toward the teeth.
The relative normal disposition of pawls 24 and 29 with respect to each other is such that pawl 29 will be projected in between the teeth of the disc prior to the Withdrawal of pawl 24 at the beginning of its releasing movement, but it will be evident from an inspection of Figs. 1 or 3 that pawl 29, because of its shape and disposition, will bear against a side of one of the teeth (Fig. 3) rather than the trough between the teeth and would stop further movement of the escapement but for the fact that the pawl lever 28 is yieldable on its pivot 28a. As a result of the improved construction, pawl 29 is immediately disposed in blocking position relative to the ratchet teeth while the pawl 24 is still being Withdrawn, and as a result there can be no slippage or failure of operation and no jamming as a result of faulty construction or operation of the ratchet disc and associated instrumentalities. Aside from the more obvious advantages of such an arrangement, there is a further advantage in that the teeth on the ratchet disc need not be accurately located, thus permitting the production of discs from stock material on slotting or milling machines with the knowledge that inevitable variations in the spacing of the teeth will not render the resulting equipment inoperative, as would be the case with other types of escapement where the ratchet discs were produced by other than precision methods.
A further advantage owing from the invention is the fact that the escapement operating mechanism may be held in operated condition and it will still be possible, when the pawl 29 is properly arranged, to step the ratchet disc away from its normal position or toward advanced pomal tooth engaging position, it, as well as the other pawl, would still yield to permit the disc to be manually or automatically displaced by the mechanism Iii-I9.
The various advantages and objects of the invention may be accomplished by modifications of the particular embodiment specifically described herein, and it is intended that the appended claims shall include all equivalent arrangements fairly coming Within their call.
Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:
l. In an escapement mechanism, an escape ment arm having a pawl thereon and pivoted to engage said pawl in the teeth of a ratchet member, a second escapement arm pivoted on said rst arm and including pawl means disposed for operative engagement with said teeth at a point displaced from the first pawl in the direction of movement of said ratchet member, spring means urging said first arm into a normal position with said first pawl engaged in the teeth of said ratchet member, spring means urging said second arm and the pawl means thereon in a direction toward said ratchet teeth, said pawl means on the second arm being normally disposed out of engagement with the ratchet teeth when the first pawl is in normal position and yieldably engaging with said teeth by movement with said rst escapement arm when the same is moved away from normal position and before the pawl thereof has disengaged said teeth.
2. In an escapement mechanism, a pawl pivoted for movement into and out of engagement with the teeth of a ratchet member, a second pawl pivotally mounted on the first pawl, means yieldably urging the rst pawl into engagement with the teeth of said ratchet member, means yieldably urging said second pawl in a direction toward said teeth on the ratchet member, stop means limiting the movement of said second pawl to a position normally out of engagement with said ratchet teeth when the first pawl is in said ratchet engaging position, said second pavvl being arranged and constructed with respect to the first pawl to yieldably engage with the toothed portion of said ratchet member for stopping engagement with the latter by movement of the rst pawl in a direction away from said teeth and prior to complete withdrawal thereof from said engagement.
CHARLES A. SOLINSKI.