US 3786657 A
A slam-style safety lock for industrial refrigerated walk-in compartments, truck bodies, and self-sealing environmental rooms, to allow egress from the interior when the lock is secured on the outside. The lock bolt is retractable, being actuated by a pivotal handle in the well known manner, and the bolt has a centrally positioned aperture in which is positioned a cam hub which engages a shoulder at the rear of the bolt, the shoulder acting as a cam follower.
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United States Patent [1 1 Loikitz Jan. 22, 1974 SLAM-STYLE SAFETY LOCK Frank F. Loikitz, Middletown, NJ.
Assignee: Instrument Systems Corporation,
' Jericho, NY.
Filed: Jan. 12, 1972 Appl. No.: 217,148
 US. Cl 70/150, 292/153, 292/169.14,
292/DIG. 31 Int. Cl E051) 65/06 Field of Search.. 70/150, 151 A, 208; 292/152,
292/153, 169.14, DIG. 31, DIG. 71
 References Cited UNITED STATES PATENTS 12/1952 Adams et a1 70/146 8/1966 Chesler 70/150 Primary ExaminerAlbert G. Craig, Jr. Attorney, Agent, or Firm-Meyer A. Gross  ABSTRACT A slam-style safety lock for industrial refrigerated walk-in compartments, truck bodies, and self-sealing mag a ,i
environmental rooms, to allow egress from the interior when the lock is secured on the outside. The lock bolt is retractable, being actuated by a pivotal handle in the well known manner, and the bolt has a centrally positioned aperture in which is positioned a cam hub which engages a shoulder at the rear of the bolt, the
shoulder acting as a cam follower.
The forward portion of the bolt has a rear lip under which is positioned a forwardly extending metal locking plate, also having a shoulder positioned just forwardly of the front surface of the cam hub. Positioned under the plate is a leaf spring maintaining constant pressure on the locking plate to actuate a drop action when locking is required.
In an unlocked position the plate is depressed inwardly so that the bolt passes along the plate without contacting it. When the lock is in a secured position rearward movement of the bolt will cause the forward portion of the plate to engage the lip on the bolt. If the cam hub is actuated from within, upon rotation, the forward surface of the hub will strike the shoulder of the plate, causing the plate to be depressed inwardly, and allowing the bolt to move rearwardly 8 Claims, 7 Drawing Figures PATEIEU JAN 2 2 mm SHEU 1 0F 2 SLAM-STYLE SAFETY LOCK BACKGROUND OF INVENTION The present invention relates to safety locks, and more particularly to a slam lock mechanism having unique structure to by-pass outer security locks from within.
Industrial refrigerator compartments utilize gasketed swing doors or self-closing doors with standard slamtype latches, the bolt catching the keeper or strike when the door is slammed shut. Because of the design of these compartments, the doors usually slam shut when someone enters the interior, and there are means on the inside of the compartment to cause the bolt to be retracted when someone wishes to leave the compartment.
Due to the value of merchandise in the enclosure, all such units contain means to lock the box for prevention of unauthorized entrance. Usually such security means consist of cylinder locks or padlocks, or both. However, if someone is accidentally caught in the interior after the locks have been secured, the results could be fatal. Complicated involved means have been developed in the past to by-pass the esterior locks, and allow the bolt to be retracted from the interior.
INVENTION Accordingly, among the principal objects of the present invention is to provide a new and novel by-pass construction which will allow egress from the interior of a box when the exterior locks have been actuated, all with a resultant overall economy of design.
Yet a further object of the present invention is to provide construction in which the interior actuating means simultaneously releases the cylinder locking means, bypasses the padlock, and retracts the bolt.
Yet another object of the present invention is to provide a simplified by-pass structure within a slam-style safety lock, which can be manufactured and produced on a relatively inexpensive basis, from inexpensive materials, and yet will be durable to a high degree in use.
BRIEF DESCRIPTION OF INVENTION The invention consists of a casing which is secured to a door by mounting screws. Housed within the casing is a handle having an exteriorly extending lever, pivoted to the casing. Located inside the casing is a retractable bolt, which is maintained in an outwardly extended position by a compression spring. The exposed portion of the bolt engages a strike in its closed position, the strike being mounted on the jamb of the door. The bolt has an inner lip, and then a centrally positioned aperture defining a rear shoulder, which acts as a cam follower and is contacted by a cam hub (which will hereinafter be referred to as the hub), pivotally mounted in the aperture and positioned in a seat located in the housing. The hub has an opening to receive a spindle which extends through the door of the compartment into the interior thereof.
Positioned below the hub is a locking plate having an aperture through which the spindle extends, the plate extending rearwardly and forwardly with an upwardly extending shoulder just forward ,ofthe front surface of the hub, and then an upwardly extending tongue. Positioned below the plate is a leaf spring which maintains upward pressure on the locking plate.
The locks include a padlock which may be passed through apertures in the casing and the wings of the handle to prevent pivotal movement of the handle. The locks also include a cylinder lock having a truncated cylindrical member designed so that in its unlocked position, the non-truncated portion of the member engages the forward portion of the plate depressing it and allowing the bolt to move without obstruction. When .the cylinder lock has been actuated to its blocking position, the non-truncated portion is positioned so as not to depress the plate which is then urged upwardly, and rearward movement of the bolt causes the forward edge or the tongue of the plate to engage the lip in the bolt, preventing other than nominal movement.
When the cylinder lock has been so actuated and the padlock hasp is in position, a person on the inside of the box may open the door by simply rotating the spindle in either a clockwise or counter-clockwise direction. This will cause the hub to pivot in either direction with its forward surface bearing against the upward shoulder of the plate, causing the tongue to be depressed, and the rear surface of the hub bearing against the cam follower shoulder of the bolt, allowing the bolt to be retracted, thus by-passing the tongue and the padlock.
The above description and objects of the present in vention will become apparent from a reading of the following description, taken with reference to the accompanying drawings, in which FIG. 1 is a perspective view of an improved slamstyle safety lock embodying the present invention, showing the lock on the door (partly cut away) and the keeper on the jamb;
FIG. 2 is an enlarged, side-elevational view of the lock, keeper and lever, with sections cut away;
FIG. 3 is a bottom planned view with the bottom plateremoved;
FIG. 4 is a side elevational view showing the cylinder lock in the unlocked position and with the padlock removed, and the handle partially actuated, causing a partial retraction of the bolt;
FIG. 5 is a view similar to FIG. 2 with the interior lever rotated and the cam hub depressing the tongue and bearing against the cam follower shoulder of the bolt;
FIG. 6 is a bottom plan view of FIGS with the bottom plate removed; and
FIG. 7 is an exploded, perspective view of the strike.
Turning to the drawings, and particularly to FIGS. 1 and 2, there is shown an improved slam-style safety lock 10 embodying the present invention and broadly comprising a yieldable latch 11, a keeper 12, the latch and keeper being respectively mounted on a door I4 and a jamb l6, and a lever 18. I
More specifically, the latch is housed in a casing 20 which may be die cast or formed in any other conventional manner.
The casing includes a somewhat rectangular shaped central portion 22 which is defined by a top wall 23, sidewalks 24, a front wall 26, and a rear wall 28 (FIG. 2). A channel 30 (FIG. 4) is defined in the central portion, and extends from the front wall 26 to the rear wall 28,.and partially down the rear wall, ending at edge 32.
A rectangular aperture 34 is also formed in the front wall 26 and a round aperture 36 in the top wall 23.
A pair of shoulders 38 extend outwardly from the lower edges of the side walls and contain apertures 40 for receipt of screws or bolts 42 to secure the latch to the door.
Positioned towards the rear of the casing and extending downwardly from the top wall 23, is an inverted cup member 44 (FIG. 2) defining a receptacle 46 for the purpose hereinafter appearing.
Also positioned within the central cavity is a post 48 with a threaded bore 50. Covering the entire cavity is a bottom plate 52 having a counter-sunk opening 54, a location dimple 56, and a back edge 58. The bore 50 and the opening 54 mate and receive a screw 60 to secure the bottom plate 54 and close off the central portion cavity. The bottom plate is flush with the base of the shoulders 38 to insure a proper fit against the door.
Turning to FIGS. 4-5, there is shown a handle 64 which is of the pivotal type and is used to retract the bolt from the strike when the latch is unlocked. The handle includes a gripping portion 66 (which is partially shown) to the rear with a forward bottom edge 67 and a forwardly placed pivot 68 which is received in apertures 69 of the handle and in apertures 70 (FIG. 6) within the casing 20. Forwardly of the pivot is a downwardly extending finger 72.
The handle is received within the channel 30 of the casing and in its normal position the forward bottom edges 67 of the gripping portion rest against the edge 32 in the rear wall 26 of the casing 20. The handle also includes two downwardly extending wings 74. The wings contain apertures 76 which are aligned with openings 78 in the casing to allow the passage of the hasp 80 of the padlock 82 (FIG. I) to provide one if the means for locking the latch.
As previously mentioned, the handle actuates a retractable bolt 84. The bolt extends through a major portion of the casing and includes a forward strike portion 86 with a rear first shoulder 87 causing a substantial decrease in thickness of the bolt, to an elongated basically rectangular portion 88 having a lip 89 (FIG. and then followed by an elongated rectangular twostepped aperture 90 defined therein. This aperture is narrower and ends at rear surface 92 of an intermediate rear shoulder 94 which receives the finger 72 of the handle 64.
Emanating rearwardly from the intermediate shoulder 94 is a second substantially rectangular portion 96 having defined therein a rear semi-cylindrical aperture 98 which terminates in a rear shoulder 100, below which is located a rear cross-member 101 having symmetrical sections 102 as defined from a center line 103. Extending rearwardly from the member and shoulder is a stop bar 104 (FIG. 4) which is aligned with a bearing shoulder 106 adjacent the rear wall 28 of the casing 20.
The shoulder 106 acts to receive and guide a compression spring 108 which encircles the stop 104 and bears against the back wall 28 of the casing 20 and the rear shoulder 100 and the member 101 urging the bolt 84 outwardly to a normal extending position with the handle in alignment with the rest of the casing. The bolt is properly guided during its retractable travel in the casing by means of the forward inner surfaces just behind the aperture 34 and the front wall 26, as well as the upward forces from the locking plate.
The bolt is received by the keeper 12 containing a roller 109 engaging the top surface of the forward portion 86 of the bolt. The keeper may be secured to the door jamb by means of screws or the like. The roller is journaled in a carriage 110 riding in a channel member 111. The carriage and roller may be adjustably positioned with respect to each other. The carriage and rol ler have abutting and mating ridged surfaces 112, 11211 and they are held in positive contact with each other by means of screws passing through opposed elongated slots and received within threaded apertures. Extending downwardly from the roller and enclosing the same are side guards 112 which completely enclose the forward portion of the bolt. This prevents tampering or forcing the bolt from outside of the door.
Extending into the cavity of the casing through the aperture 36 is a standard cylinder lock 114. As shown in FIGS. 2, 4-6, extending downwardly from the lock 114 is a cylindrical support 116 carrying a drop action or truncated cylindrical member 118.
More particularly, the member 118 consists of an annular shoulder 120 (FIG. 5) from which depends a cylindrical surface 122. At its longest length the surface extends down to a bottom surface 124 which in the end view (FIG. 3) represents a portion of a circle. Commencing from the forward edge 126 of surface 124, a sloping surface 128 extends upwardly towards the surface 122, meeting it at edge 130 which is its shortest length.
Positioned just below the member 118 and extending towards the rear of the casing is the locking plate 132 (FIGS. 2, 4, and 5). More specifically, it consists of an upwardly extending forward tongue portion 134 terminating in an edge 136. The tongue joins a second upwardly extending portion 138 at 140, the two portions forming an obtuse angle of greater than 90. The second portion 138 terminates in a downwardly extending shoulder 142 at 144 and then at 146 the tongue has a portion 148 which extends rearwardly and substantially horizontally, and has an aperture 150 defined therein and terminating at a rear edge 152. Located just beneath the tongue is a leaf spring (FIG. 2) 154 having an upwardly extending forward portion 155 which extends just forwardly of the joinder 140 of the portions 134, 138; a horizontal central portion 156 with an aperture 157 defined therein; and an upwardly extending rearward portion 158, whose rear edge 159 contacts the rearward portion 148 of the tongue. The purpose of the leaf spring is to constantly urge and maintain the locking plate in an upward direction, and because of the non-movable mechanism in the rear of the latch, the force is all translated to the forward portion of the tongue.
The receptacle 46 in the dish 44 is designed to receive a cam hub 160. The hub includes (FIG. 2) a cylindrical body section 162 which is received within the apertures 150, 146, and 98. The cam hub also includes two symmetrical arms 164, 166 (FIG. 3 having rear bearing shoulders 168, 170, and a forward bearing shoulder 172. The rear shoulders face the shoulder 101 and the forward shoulder faces shoulder 146.
The hub also includes a central aperture 174 which may be non-circular in cross-section and is shown as square. The aperture is designed to receive a spindle 176 (FIG. 2) of similar cross-section and dimension, which forms a portion of the lever 18. The lever also consists of an arm 178, the arm and the inner portion of the spindle being located within the interior of the environment when the unit is assembled. The spindle is of sufficient length to pass through the entire door and may have an ascutcheon or rose 180 to receive the release lever 18. The lever is secured to the inside of the door by screws (not shown) passing through the rose.
Because of the simplified construction of the locking by-pass means, the resultant structure of the entire safety latch is not only more economical, but durable to a high degree in use. FIG. 4 shows the normal operational position of the cylinder lock 114 when the refrig erator box is in use. The lock is turned so that the 'surface 124 is to the left, and bears against the forward edge 136 of the plate 132 depressing it. Thus, when the handle 64 is actuated and the finger 72 contacts the surface 92 of shoulder 94, the bolt 84 passes into the latch without meeting any obstructions until the stop bar 104 contacts the rear wall 106. However, the handle 64 allows opening of the door before-this inward travel position is reached.
In order to lock the door solely with the cylinder'lock 114, the key is turned so that the member 118 assumes the position as shown in FIGS. 2, 3, 5, and 6. In this position the surface 124 is to the right as viewed in the drawings and the leaf spring 154 forces the plate 132 upwardly until the upper surface of portion 138 contacts surface 124. Furthermore, the slope angle of the surface 128 is closer to the vertical than the slope of the portion 134 so that there is no contact between these sections in this position. In this position, when the handle 64 is turned, rearward movement of the bolt is stopped because the forward edge 136 engages the lip (FIG. 2) 89 of the bolt 84. Additional security can be provided by passing the hasp 80 of a standard padlock 82 through the apertures 76, 78.
However, in these positions, it is still possible to open the latch, by-passing both of the locks, from the interior of the box. This is done by rotating the handle 178 of the-lever 18 in either direction, clockwise or counterclockwise. This causes the spindle to rotate and since the spindle is secured to the cam hub within opening 174, which is non-circular, the cam itself turns in either direction. As a result, either of the surfaces 168, 170 may bear against the rear cam follower shoulder. 100 to initiate retraction of the bolt. Simultaneously, the forward shoulder 172 contacts the shoulder 142 of the tongue 132 both of which are somewhat rounded to insure proper co-action. Continued movement of the cam causes the plate to be forced downwardly so that the edge 136 is forced below the lip 89, and this allows the bolt to move rearwardly. Because of the forward length of the aperture 90, the finger 72 also does not prevent sufficient rearward movement of the bolt for it to disengage from the strike.
All that is necessary for the system to work is that the force on the shoulder 100 overcome the force within the compression spring-Since the handle is not actuated, there is no need for any complicated mechanism to release the handle. The only moving element within the latch is the bolt itself and the cam, everything else being completely by-passed.
The tongue and the leaf spring are fabricated from strong durable materials, and thus the whole unit will be capable of extended use without break-down.
The terms and expressions which have been employed here are used as terms of description and not of limitation and there is no intention in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that various modifications are possible within the scope of the invention claims.
What is claimed is:
1. An improved slam-style safety lock for enclosed environments allowing egress from the interior when the exterior lock has been actuated, comprising:
a. a retractable bolt b. means for housing the bolt, the housing having an opening, to allow passage of the bolt therefrom c. means to secure the housing means to a door allowing access into the environment d. keeper means on the door jamb in alignment with and receiving a portion of the bolt in its normal extended position when the door is closed e. means mounted on the housing means for actuating the bolt between its engagement position with the keeper means to which it is normally yieldingly biased and its retracted position, out of engagement with the keeper means f. the bolt having an aperture, cam means within said aperture g. hand grip and spindle means movably mounted on the door inside the environment, the spindle means passing through the door and engaging the cam means for retracting the bolt from inside the environment without utilizing the actuating means,
h. a locking plate positioned inwardly of the bolt, the
plate having an outwardly extending forward portion, the bolt having a lip adjacent the forward portion i. means urging the plate outwardly and particularly the forward portion into the path of travel of the bolt and engagement with the lip j. locking means positioned within the housing and extending inwardly toward the locking plate, the locking means in its locking position being free of the locking plate which prevents opening of the lock from the exterior, and the locking means having a second position which pushes the locking plate out of the path of travel of the bolt so that the lock may be actuated from the exterior k. and means operable only from inside the environment for pushing the locking plate inwardly to a position free of said lip, thus allowing unobstructed rearward movement of the bolt by actuation of the hand grip and spindle means even when such movement is precluded from the exterior.
2. The invention according to claim I, the means urging the plate outwardly, being a leaf spring positioned inwardly of the locking plate.
3. The invention according to claim 1, the locking plate having a shoulder adjacent the forward portion of said cam means.
4. The invention according to claim 3, the cam means having a forwardly extending shoulder facing and adjacent to the shoulder of the locking plate so that upon actuation of the cam means in either rotational direction, the forward shoulder of the cam means contacts the shoulder of the locking plate and upon extended rotational movement, forces the locking plate inwardly to a position out of the path of travel of the lip of the bolt.
5. The invention according to claim 4, the locking plate having a substantially planar portion placed in between and connecting the shoulder and the outwardly extending forward portion, and then having another rearwardly extending substantially planar portion having an opening defined therein to allow passage of the spindle-means into engagement with the cam means.
6. The invention according to claim 5, the means urging the plate outwardly, being a leaf spring positioned inwardly of the locking plate.
7. The invention according to claim 6, the leaf spring having an outwardly extending forward portion and a central portion depending rearwardly therefrom, having an aperture defined therein to allow passage of the spindle means, and an outwardly and rearwardly extending rear portion, the forward and rear portions engaging the inward surfaces of the locking plate, and the forces being translated from the leaf spring to continually urge the locking plate outwardly.
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