BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to meter clamping rings for securing and locking a utility meter cover to its base housing.
2. Description of the Prior Art
Utility electric meters have transparent covers that are secured to the meter mechanism in a base unit. The covers are typically circular cylindrical transparent glass cup shaped members and have an annular rib at an edge flange. The meter base unit has a circular cylindrical housing with an annular flange that abuts the cover edge flange. A meter ring engages the flanges of the cover and base unit clamping the cover to the base unit housing.
The clamping ring is usually a metal split ring with a flange at a first end with an aperture. A second end adjacent to the first end has a locking device attached. The locking device is used to lock the two ends together. The locking device has a bore which receives a locking bolt or barrel, which is a separate piece which is releasably inserted into the device bore. The barrel is inserted into the bore to engage the flange aperture and when engaged precludes the withdrawal of the flange. The barrel also includes a mechanism that locks the barrel in place in the locking device bore. See U.S. Pats. Nos. 4,674,304 and 4,446,603 to Guiler, and U.S. Pat. No. 4,008,585 to Lundberg, for example.
U.S. Pat. No. 4,015,456 discloses a plunger operated lock, which more recently has been used with meter rings to lock the rings in the clamped state. The plunger is in the form of a barrel, which is inserted into the lock bore as discussed above. The lock opened by a separate retracting device, known in this art as a key, which engages the plunger or barrel and retracts the plunger from its lock state and withdraws it from the bore. The key may take different forms and examples of which appear in FIGS. 8 and 23 herein, and which are respectively known in this industry as F and G type keys. The plunger is a separate unit that is inserted into the bore of the lock housing secured to one end of the meter clamping ring and which engages a bore of a second element secured to the other end of the meter clamping ring to lock the ring ends together in the locked state, clamping the ring to the meter and securing the meter cover to the meter base unit.
U.S. Pat. No. 5,301,524 discloses a repairable key for a plunger lock of the type used for locking utility meter clamping rings and is incorporated by reference herein in its entirety. This key has a camming frusto-conical head which engages split resilient fingers at the end of the key. The camming head spreads the normally closed fingers apart to cause the fingers to releasably frictionally engage the bore of a clamp ring locking plunger. The spread fingers when cammed radially outwardly, frictionally grip the interior of the locking plunger bore into which the fingers of the key are inserted, enabling the plunger to be pulled free of the plunger lock housing bore to free the two ends of the ring and release the meter cover from the base unit. The key has a camming lever which when rotated cams the fingers apart and also lifts the fingers and grasped plunger from the lock bore. A key of this type is commonly used today with utility meter plunger locks. Utility meter employees thus carry with them keys of this type to open the meters for repair or internal meter work.
U.S. Pat. Nos. 5,315,849 and 5,378,030 disclose still other types of plunger lock devices for use with utility meter clamping rings. As in the previously discussed patents, these plunger locks are separate from the utility meter clamp rings.
SUMMARY OF THE INVENTION
The present inventors recognize a problem with the aforementioned plunger lock devices for use with utility meter clamping rings. Utility meters are installed initially by electricians not associated with utility companies that utilize and service the meters. The electricians can not lock the meters with clamping rings as they do not have the associated keys. The keys are important because the utility company needs to exercise tight control over them. The keys permit the meters to be opened and thus tampered with if the keys are in the wrong hands. Control of the keys presents a problem to the utility companies. Each time a meter needs to be clamped with roost clamping devices in use, a service technician is required to carry a key to lock the plunger lock. Thus for each installed meter that requires a clamping ring, a technician and key are required to lamp the ring to lock the meter. This requires numerous keys. Since such keys can open the clamping ring, tight control of such keys requires a tracking system to keep track of all keys in use at all times. This can be costly and cumbersome.
Also, the plunger locks generally are separate devices and sometimes can be lost or become inoperative. This can create a further problem with respect to locating or carrying spare plunger locks, which is also costly and cumbersome to utility companies which have hundreds, if not thousands, of such meters which require service.
There are clamping rings available which include plunger locks attached to the clamping rings. These plunger locks do not need keys to lock, but do need to be manually actuated to lock the ring by pushing the lock into locking engagement. This creates a problem if the operator overlooks pushing the lock into locking position.
A solution to these problems according to an embodiment of the present invention is provided by a clamping ring assembly comprising a split ring for clamping a cover to a base, e.g., a utility meter cover and base. The ring has opposing adjacent free ends. A locking device has mating male and female elements attached to the respective opposing free ends of the ring. The mating male and female elements automatically lock the ring free ends together in a cover clamping mode when the mating male and female portions become engaged in the clamping mode.
In one embodiment, the female element includes a reciprocating latch for engaging the male element in a lock position of the latch, the latch reciprocating on an axis, the latch having a bore for receiving a key for frictionally engaging the latch and for axially displacing the latch to an unlock position disengaged from the male element along the axis.
In a further embodiment, the female element includes a housing with a reciprocating resiliently secured latch attached to a first ring end and interior of the housing, the male element comprising a blade attached to a second ring end and having an aperture for automatically receiving the resiliently secured latch in a locking mode, the housing for receiving the blade in the housing interior, the latch for locking the blade to the housing upon insertion of the blade into the housing interior.
Preferably the housing has a slot for receiving the blade.
In a further embodiment, the locking device is arranged to be permanently locked requiring either the locking device or the ring of the ring assembly to be destroyed to unlock the assembly.
In accordance with an embodiment of the present invention, the latch does not need a key to lock, locks automatically upon clamping the ring to the utility meter and does not separate from the housing in the unlock state of the blade, avoiding the problems with the prior art ring clamping devices. One problem avoided is where a key is required for installation of each clamping ring, requiring numerous keys and their attendant tight control. A further problem is avoided where the separated plungers may become lost or damaged, such as when dropped or otherwise mishandled, and require replacement plungers to be carried by service technicians, not necessary with the various embodiments of the present invention. With the embodiments of the present invention, the service technician need not carry a key to install the clamping ring minimizing the extent to implement key control for numerous keys no longer necessary. Installation of meter clamping rings is widespread as compared to merely servicing an occasional meter for repair, which requires a key for opening the meter. In addition, non-utility company workers such as electricians can install the clamping rings according to embodiments of the present invention, since no key is required. This results in substantial cost savings.
In a further embodiment, there is at least one weakening groove in the ring for destructively opening the locked ring for that embodiment in which the locking device can not be key opened.
In a further embodiment, the locking device has no key and can not be non-destructively opened.
In as further embodiment, an anti tampering split sleeve is used in a locking device for precluding tampering unlocking of a latch of the type for use with an F type key.
IN THE DRAWING
FIG. 1 is an isometric view of an electric utility meter with a clamping ring and locking device attached according to an embodiment of the present invention;
FIG. 2 is an isometric view of the clamping ring used in the embodiment of FIG. 1 without the ring locking device attached;
FIG. 3 is an isometric view of a portion of the ring locking device showing the adjacent free ends of the ring of FIG. 2;
FIG. 4 is an isometric view of the locking device of FIG. 1 which is attached to the free end of the ring of FIGS. 2 and 3 adjacent to the end with a blade having an aperture used for locking the blade to the locking device;
FIG. 5 is an exploded view of the locking device of FIG. 4 showing the components of the device in section with the device housing shown partially in section for use with an F type key (FIG. 8);
FIG. 6 is a side elevation view of the locking device housing of FIGS. 1, 4 and 5, shown partially in section for use with the F type key, FIG. 8;
FIG. 7 is a sectional side elevation view of the embodiment of the locking device of FIGS. 5-6 in the locked state for use with an F type key, FIG. 8;
FIG. 7
a is a sectional side elevation view of an alternate embodiment of a locking device similar to that of the device of FIG. 7 for use with a G type key, FIGS. 23-26;
FIG. 7
b is a side elevation view of a component used in the embodiment of FIG. 7a;
FIGS. 8 and 23 are sectional elevation views of representative prior art F and G type keys, the F type key for unlocking the lock device of FIG. 1, the G type key for use with the locking device of FIG. 7a;
FIG. 9 is a top plan view of a clamping ring in the locked state with a locking device according to a second embodiment without the utility meter in place;
FIG. 10 is a more detailed bottom plan view of the clamping ring locking end similar to the view of FIG. 9 in the locked state;
FIG. 11 is a side elevation sectional view of the locking device of FIG. 9 taken along lines 11-11;
FIG. 12 is a top plan view of the clamping ring of FIG. 9 without the locking device attached;
FIG. 13 is a fragmented side elevation view of a portion of the ring of FIG. 15 showing weakening grooves in the ring to permit destructive removal of the locked ring from the utility meter;
FIG. 14 is a side elevation sectional view of the locking device of FIG. 12 taken along lines 18-18;
FIG. 15 is an isometric view of the locking ends of the clamping ring of FIG. 15;
FIG. 16 is a sectional side elevation view of a locking device according to a further embodiment employing a sleeve according to FIGS. 17 and 18 to prevent picking of the latch used with the F type key of FIGS. 4-6, 9-11 and 14;
FIG. 17 is a side elevation view of the sleeve of FIG. 16 in more detail;
FIG. 18 is an isometric view of the sleeve of FIGS. 16 and 17:
FIG. 19 is an isometric view of the interior of the latch of the embodiment of FIG. 16;
FIGS. 20-22 are sectional side elevation views of the device of FIG. 16 in combination with its associated unlocking F type key, FIG. 8, showing various stages of releasing the locking latch of the locking device from its locked state with the antipicking sleeve in place;
FIGS. 24-26 are sectional side elevation views of the device of FIG. 7a in combination with its associated unlocking G type key, FIG. 23, showing various stages of releasing the locking latch of the locking device from its locked state;
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIGS. 1 and 2, meter 10 comprises a base 12 mounted on a support (not shown). A transparent cover 14 is clamped to the base 12 by meter ring clamp assembly 16 in a clamping mode, i.e., locked state, of the assembly. The assembly 16 has locked and unlocked states. The cover 14 has an annular radially outwardly extending flange 18 which abuts an annular radially outwardly extending flange 20 on the base 12. The ring clamp assembly 16 comprises a U-shaped (in portions as described below) generally annular stamped sheet steel ring 22, preferably stainless steel. The ring 22 comprises a base wall 21, an upper radially inwardly directed flange 32 and lower spaced radially inwardly directed flanges 34 and 34′. The base wall 21 and flanges 32, 34, 34′ form an annular channel that receives the cover and base flanges 18, 20 (FIG. 1). The flanges 34, 34′ are of circumferentially different size portions that partially extend about the ring circumference in spaced relationship to each other.
The ring 22 is split at location 24 forming the ring 22 with two adjacent facing free ends 26 and 28. A ring locking device 30, forming a female element, FIG. 1, is attached to free end 28 of the ring, FIG. 2. The female locking device 30 locks the two free ends 26 and 28 together with the ring clamped about and to the flanges 18 and 20 of the meter 10, locking the cover 14 to the base 12 in the locked state.
FIGS. 2 and 3 illustrate the ring 22 without the locking device 30 attached, FIG. 3 showing the split location 24 in more detail. The ring sections formed by the split at location 24 are resilient so that the free ends 26 and 28 can be resiliently displaced away from and toward each other in a circumferential direction as known in this technology. This resilient displacement permits the ring free ends to be displaced radially away from and toward the cover 14, FIG. 1, to either remove or clamp the ring in place to lock the cover to the meter base 12.
In FIG. 3, end 26 has an end portion 36 and end 28 has end portion 38. Both end portions are U-shaped and extend approximately at right angles to the circumferential portions of the attached ring 22 section. The end portions 36 and 38 are juxtaposed with respect to each other. A flat blade 40, forming a male element mates with the female element, the locking device 30, which is attached to end portion 36. The flat blade 40 extends perpendicular from the ring end portion 36 toward the facing ring end portion 38 at ring end 28. The blade 40 passes through a slot (not shown) in the ring end portion 36. The blade 40 has an enlarged end 37 that is welded to the ring end portion 36 at welds 42. The flat blade 40 has a chamfered end 44 and a through aperture 46.
The end portion 38 has a slot 48 through which the flat blade 40 passes as shown in FIG. 3. The flat blade 40 can be totally withdrawn from the slot 48 due to the resiliency of the ends 26 and 28 with respect to each other.
In FIGS. 4-7, locking device 30 has a housing 50, a plunger latch 52 and a latch guide 54. The housing 50 has a bore 56 having a longitudinal axis 60. The bore 56 is in communication with slot 58, which defines a plane that is at right angles to the longitudinal axis 60 of the bore 56. The slot 58 is in communication with chamber 62 of the housing 50, FIGS. 5 and 6. A camming member 64 is in the chamber 62 and includes an inclined surface 66. The member 64 is adjacent to the slot 58 such that the inclined surface 66 intersects the plane of the slot 58 at an angle of inclination. The surface 66 serves as a guide ramp for the blade 40 as the blade enters into the slot 58 in the direction of the arrow 65, FIG. 6.
In FIG. 6, a rib 68 is also molded to the housing 50 in the chamber 62 adjacent to and spaced from the inclined surface 66 of the camming member 64. The rib 68 serves as a guide for the blade 40 as it enters into the slot in cooperation with the camming member 64. The chamfer 44 at the blade 40 leading edge may engage the rib 68 for guiding the blade during insertion into the slot 58. The member 64 and rib 68 may be molded in one piece with the housing 50, which may be cast metal, such as zinc and the like. A further rib 67, FIG. 5, extends into the chamber 62 from housing wall 69. The ribs 67 and 68 serve to secure the ring free end 28 (FIG. 3) to the housing as shown by way of example in FIG. 11 in a further embodiment of a ring free end 142 and corresponding respective ribs 270 and 268.
In FIG. 5, the guide 54 is circular cylindrical steel having a circular cylindrical bore 70 for receiving the latch 52. A circular cylindrical bore 72 of smaller diameter than bore 70 is next adjacent to and in communication with the bore 70 and forms a shoulder 73. A still smaller diameter bore 74 is next adjacent to and in communication with the bores 70 and 72, all bores being coaxial with each other and with axis 60. The guide 54 is inserted into and press fit in the housing bore 56 (FIG. 7). A further bore 76 of larger diameter than bore 72 is recessed from the edge 78 and opening 80 at the edge 78 of the guide 54. The opening 80 is of smaller diameter than bore 76. A pliable flap (not shown) made of rubber or similar material for forming a seal has a central key receiving slit and may be optionally inserted into the bore 76 for enclosing the bores 70, 72 and 74. If the flap is not used, then the small diameter bore 74 may extend to adjacent to the outer surface of the body of the guide 54. In this case, the bores 76 and 80 are not necessary. The guide 54 has an annular tapered surface 75 adjacent to end surface 77.
The latch 52, FIG. 5, is circular cylindrical steel with a central axially extending bore 82 that is coaxial with the axis 60 when assembled to the housing 50 and guide 54. A blind smaller diameter bore 84 is between bore 82 and the bottom wall 86 of the latch 52. A coil compression spring 88 is in the bore 82. The bottom wall 86 has an annular peripheral chamfer 90 which serves as a ramp for receiving the blade 40 during insertion of the blade 40 into the housing slot 58, FIG. 7.
In FIG. 7, the latch 52 and spring 88 are then inserted into the bore 70 of the guide 54 with the spring 88 abutting the shoulder 73 (FIG. 5) of the guide. The spring normally biases the latch 52 in a blade locking direction 92 when the guide 54 and latch 52 are inserted into the housing bore 56. The latch 52 chamfer 90 at bottom wall 86 is inserted first into the housing bore 56. The guide 54 is press fit into the housing bore 56 so it is held by high interference friction forces with the latch 52 located in and captured to, and for reciprocation in, the guide bore 70 in directions 92, 93 (FIG. 7). In FIG. 5, the end portion 87 of the latch 52 bottom wall 86 and the chamfer 90 are located in the slot 58, FIG. 7. The latch 52 bottom wall 86 bottom surface normally abuts surface 58 of the slot 58, FIG. 5, as best seen in FIG. 7. The latch 52 is spring loaded by spring 88 so that it can be resiliently retracted from the slot 58 by the insertion of the blade 40 via the blade chamfer 44 (FIG. 3).
The housing 50, FIG. 6, has a pair of opposing slots 94 adjacent to housing end 96 at which an unlocking key is inserted. The slots 94 receive an optional padlock security seal or other type of security seal (not shown) which is used to provide evidence of tampering with the lock 30. The hollow region 98 in the housing 50 minimizes the amount of material used in forming the housing and serves no functional purpose in the operation of the locking device 30.
FIG. 8 depicts a conventional prior art F type key as used in the lock described in the aforementioned U.S. Pat. No. 5,301,524 incorporated by reference herein and which may be used with the lock 30, FIGS. 5-7. Key 100 has an axially displaceable rod 102 having a frusto-conical camming head 104. The head 104 engages split resilient fingers 106 at the end of sleeve 113 of the key 100. The camming head 104 spreads the normally biased closed fingers 106 apart to cause the fingers to releasably frictionally engage the side wall of the bore 84 (FIG. 5) of the clamp ring locking latch 52. The fingers 106 are spread apart by raising the camming head 104 (FIG. 8). The head 104 is raised when the handle 108, a cam device, is rotated in the counterclockwise direction 110 as shown in FIG. 3.
The fingers are spread radially outwardly by rotation of the handle 108 cam 119 against the top surface 115 of the key cap 117. The spread fingers form an enlarged diameter that frictionally grips the smaller interior of the locking latch bore 84 into which the fingers 106 of the key are inserted. As the handle is rotated, its camming action at the same time lifts the sleeve 113 of the key 100 in direction 112. This lifting action causes the expanded fingers to pull the latch 52 in the withdrawal unlocking direction 112, and in direction 93, FIG. 7.
This action disengages the pulled latch from the blade 40 aperture 46 (FIG. 3). The key 100 camming lever 108 and cam 119 are rotated in direction 110 about pin 107, which is pinned to shank 109. This camming action also lifts the shank and the rod 102 which is attached to the shank 109, and thus the head 104 in direction 112. This lever action cams the fingers 106 apart and thus at the same time also lifts the shank 109 and the fingers 106 in direction 112. The expanded fingers having gripped the latch 52, FIG. 7, thus also lift the latch 52 out of engagement with the blade 40 aperture to unlock the blade.
In operation, in FIG. 7, the blade 40 of the ring 22, in the unlocked state, is inserted into the slot 58 of the locking device 30 to place the ring in the locked state. The chamfered edge 44 of the blade engages the bottom chamfered end portion 87 of the latch 52 (FIG. 5). This action resiliently axially displaces the latch 52 in the retracted direction 93, FIG. 7, as the blade 40 is being inserted into the slot 58. When fully inserted in the slot, in the meter cover clamping mode lock position of the latch, the latch 52 bottom end portion 87 snaps into the aperture 46 of the received blade 40 (FIG. 3). This action automatically locks the blade 40 to the locking device 30 in the locked state. Thus, the free ends of the ring 22 are locked together (FIGS. 1-3) immediately upon insertion of the blade into the slot 58. The latch 52 is permanently attached to the housing 50 and is not removed as in the prior art locking plunger devices. No separate plunger is required or needed to be carried by a person and inserted into the locking device.
There is a tampering problem in industry in use of the F type key in the lock device of FIGS. 5-7. The problem is that thieves may defeat the lock 30. Therefore, the lock 30 of FIGS. 5-7 needs to be modified to address the tampering problem.
The clamping ring lock 97 embodiment of FIG. 16 addresses this tampering problem. In FIG. 16, parts with identical reference numerals as the embodiment of FIGS. 4-7 are identical. The lock 97 has most of the same parts as the lock 30 of FIGS. 4-7 except for the sleeve 99. The sleeve 99 prevents tampering with the latch 52 in an attempt to defeat the lock.
In FIG. 17, the sleeve 99 is a steel tube that has a longitudinally extending slit 101. The slit is arranged such that the sleeve 99 is radially resilient in a direction normal to axis 60, which is the longitudinal axis of the latch 52, guide 54 and of the sleeve 99. The sleeve has an outer diameter d that is slightly smaller than the diameter of the latch bore 84. Thus the sleeve 99 may axially displace in the bore 84 along axis 60. The diameter d of the sleeve 99 however is greater than the diameter d′ (FIG. 16) of the bore 74 in the guide 54 formed by flange 103 of the guide 54. Thus the flange 103 and latch bottom wall 86 (FIG. 5) axially capture the sleeve 99 therebetween. The guide 54 is frozen in place to the housing 50 since it is press fit to the housing 50 bore 56, FIG. 16, in interference fit. The latch 52 is captured to the housing 50 between the housing wall 107 and the guide shoulder 111. The latch 52 is free to axially displace in the guide 54 bore 70 in directions 92, 93.
Spring 88 is captured between flange 103 of the guide 54 and the shoulder 105 of the latch 52 (FIG. 19). The spring 88 resiliently urges the latch in the blade 40 locking direction 92. The latch 52 sleeve 99 and spring 88 are first assembled to the guide 54 before the guide is fixed to the housing 50 bore 56. Then the latch 52, sleeve 99, spring 88 and guide 54 assembly are inserted as a subassembly into the housing bore 56 and fixed thereto in the position of FIG. 16. This arrangement permanently captures the latch, the sleeve and the spring to the guide in the housing bore 56.
In operation, a tampering tool can only engage the sleeve 99. If the tampering tool engages the sleeve it can only slide the sleeve partially along the axis 60 until the sleeve abuts the flange 103. Thus a tampering tool can not defeat the lock. This lock 97 is used with the F type key of FIG. 8.
In operation, in FIGS. 20-22, the locking device 97 with the anti tampering sleeve 99, is shown schematically in section for purposes of illustrating its operation. To release the free ends 26 and 28 (FIG. 2) of the ring relative to each other to the unlocked state from the locked state, the sleeve 113 of the key 100 is inserted into the bore 82 (FIG. 5) of the latch 52 until the fingers 106 (FIG. 8) abut the bottom of the blind bore 84 in the latch 52, FIG. 20.
In FIG. 21, the camming handle 108 is then rotated in direction 110 about pin 107 which pulls the camming head 104 (FIG. 8) in directions 112 and 93 (FIG. 7). At the same time the fingers 106 are expanded to grip and spread apart the split sleeve 99. The expanded sleeve 99 then grips the latch 52, FIGS. 21 and 22, inside of the bore 84. The handle 108 is further rotated in direction 110, FIG. 22, which pulls the rod 102 and head 104 (FIG. 8) in the latch release directions 112 and 93 pulling the sleeve 99 and the latch 52 gripped by the sleeve 99 at the same time. This frees the latch from the locking engagement with the aperture 46 of the blade 40.
The ends 26 and 28 of the ring 22, FIG. 2, can then be separated and the cover 14 (FIG. 1) removed in the unlocked state. The key 100 handle 108 is rotated back to the original position of FIG. 8 from that of FIG. 22 to release the fingers from gripping the sleeve 99 and the latch 52. The key is removed from the lock 30. The key, as explained above, is only used to place the ring assembly in the unlocked state and is not used to place the ring assembly in the locked state.
To lock the cover 14 to the base 12, FIG. 1, the procedure discussed above in connection with FIG. 7 is followed. No externally separate carried plunger is necessary to lock the ring free ends together. The mere full insertion of the blade 40 (permanently attached to the ring end 36 (FIG. 3) into the lock device slot 58 of the housing 50 (FIG. 7) automatically locks the ring free ends together in one simple operation.
In FIG. 9, a meter ring clamp assembly 114 according to a further embodiment includes a stamped sheet steel ring 116, preferably stainless steel, and a locking device 118. The ring 116 is generally similar to and split similar to the ring 22, FIG. 2. The ring 116, FIGS. 12 and 13, comprises a U-shaped channel member that includes a relatively flat base wall 120, an upper flange 122 and an array of spaced radially inwardly directed lower flanges 124, 126, 128, 130 and 132. The flanges extend from the base wall 120 to form a channel like structure. The ring 116 has a pair of spaced weakening grooves 134 in the base wall 120 and in the upper and lower flanges forming a weak region 136 in the base wall and adjacent flange portions. The weak region 136 forms a tear strip that can be destructively torn with a pair of pliers or similar tool to open and remove the ring from the utility meter cover.
In FIGS. 12 and 15, the ring 116 is split at location 138 forming the ring 116 with two adjacent facing free ends 140 and 142. Ring locking device 118, FIG. 14, is attached to free end 142 of the ring. The locking device 118 locks the two free ends 140 and 142 together with the ring clamped about and to the meter base and cover flanges 18 and 20, FIG. 1, locking the cover 14 to the base 12.
FIGS. 12 and 15 illustrate the ring 116 without the locking device 118 attached, FIG. 15 showing the split location 138 in more detail. The ring sections terminating at the ends 140 and 142 formed by the split at location 138 are resilient so that the free ends 140 and 142 can be resiliently displaced away from and toward each other in a circumferential direction as known in this technology. This resilient displacement permits the ring free ends 140 and 142 also to be displaced radially away from and toward the center of the ring to either remove or clamp the ring in place to the cover 14 (FIG. 1).
In FIGS. 12 and 15, ring end 140 has an end portion 144 and ring end 142 has end portion 146. The end portions 144 and 146 are U-shaped in cross section forming a channel as does all of the ring 116 and extend approximately at right angles to the circumferential portions of the attached ring 116 section. The end portions 140 and 142 are normally juxtaposed with respect to each other as shown in FIGS. 12 and 15. A flat blade 148 is attached to end portion 144. The blade 148 extends perpendicular to end portion 144 toward the facing end portion 146. The blade 148 passes through a slot in the end portion 144 and has an enlarged member 152 that is welded to the end portion 36 at weld 150. The blade 148 has a chamfer 154 at the end 156 of the blade and a through cylindrical aperture 158, which serves to lock the blade as will be described below. A rectangular opening 160 is at the end 156 of the blade 148 for receiving a security seal (not shown). The security seal provides tamper evidence in case the lock 118 is tampered with and opened. The ring end portion 146 has a slot 162 through which the blade 148 passes as shown in FIGS. 12 and 15.
In FIGS. 11 and 14, the lock 118 includes a housing 250, a plunger latch 252 and a latch guide 254. The housing 250 has a bore 256 having a longitudinal axis 260. The bore 256 is in communication with a transverse slot 258, which defines a plane that is at right angles to the longitudinal axis 260 of the bore 256. The slot 258 is in communication with chamber 262 of the housing 250. A wedge shaped camming member 264, FIG. 11, is in the chamber 262 and includes an inclined surface 266. The member 264 is adjacent to the slot 258 such that the plane of its inclined surface 266 intersects the plane of the slot 258. The surface 266 serves as a guide ramp for the blade 148 as the blade enters into the slot 258 via chamber 262.
A rib 268 is molded to the housing 250 in the chamber 262 adjacent to and spaced from the cam surface 266 of the camming member 264. The rib 268 serves as a guide for the blade 148 as it enters into the slot 258 in cooperation with the camming member 264. The chamfer 154 at the blade 148 leading edge may engage the rib 268 for guiding the blade during insertion into the slot 258. The member 264 and rib 268 may be molded in one piece with the housing 250, which may be cast metal, such as zinc and the like. A second rib 270 extends into the chamber 262 from housing wall 272. The ribs 268 and 270 lock the ring 116 at end 142 to the housing 118 in the housing chamber 262.
In FIGS. 11 and 14, the guide 254 is circular cylindrical steel having a circular cylindrical blind bore 274 for receiving the cylindrical latch 252. The bore 274 terminates at end wall 269 of the guide 254. The latch 252 has a circular cylindrical blind bore 275 in which is received a coiled compression spring 276. The spring 276 is also located in bore 274 of the guide 254. The spring 276 is compressed between the latch 252 and the end wall 269 of the guide 254. The guide 254 is permanently fixed to the housing 250 by interference press fit in the housing bore 256. As a result of the compression force of the spring 276, the latch 252 is normally resiliently biased in direction 273, FIG. 14, into and across the slot 258 of the housing 250 into engagement with housing wall 271 as shown in FIGS. 11 and 14.
As seen in FIGS. 11 and 14, the latch 252 end surface is chamfered. The chamfer is located in the slot 258. The end surface of the latch 252 normally abuts the surface of the wall 271. The latch 252 is spring loaded by spring 276 so that it can be resiliently retracted from the slot 258 in response to insertion of the blade 148 into the slot 258. Because of the presence of the guide upper enclosure wall 269, no key can access the latch 252 and open it. In this way the ring or lock must be destructively opened. The weakening grooves 134, FIGS. 12, 15 and 16 serve this purpose.
In FIG. 7a, an alternative embodiment of a meter ring lock 30′ is shown. In FIG. 7a, reference numerals that are identical to the reference numerals in FIG. 7 refer to identical parts. Reference numerals in FIG. 7a that are the same as reference numerals in FIG. 7, but are primed (have (′)), are different than the parts in FIG. 7 with the same reference numerals without the prime. The housing 50, guide 54 and spring 88 are identical to components in FIG. 7 with the same reference numerals. The latch 52′ of FIG. 7a is different than the latch 52 of FIG. 7. The latch 52′ has a through bore 121 in bottom wall 86′ which is in communication with the bore 84 of the latch 52′.
In FIG. 7b, a post 123 is secured in the bore 121 of the latch 52′ of FIG. 7a. The post 123 comprises a cylindrical base 125 which is mounted in the bore 121 and fixed thereto by press fit or any other arrangement such as by bonding and so on. The post 123 has a post portion 129 that extends upwardly from the base 125. The portion 129 is frusto-conical and terminates at its upper end 131 in a further portion 133 that is conical. The post 123 is preferably steel or other metal but may be molded plastic for example. The portions 129 and 133 are located centrally within the bore 84. As noted above, there is a tampering problem with the use of the latch 52 of FIG. 5.
The latch 52′ of FIG. 7a employing the post 123 of FIG. 7b addresses this problem. The post 123 tends to prevent a tampering tool from defeating the lock. The post takes up a significant amount of space in the bore 84 allowing little room for the tampering.
Because of the presence of the post, the F type key of FIG. 8 is not used as this key does not fit with the post 123 present. Instead, the G type key 100′, FIG. 23, is used with the latch 52′. In FIG. 23, key 100′ has components with the same reference numerals as the key 100, FIG. 8, except the key 100′ reference numerals are primed. The parts with the same numerals in FIGS. 8 and 23, are identical, and where primed, are substantially the same as the parts with the same unprimed numerals and differ only slightly. The rod 104′ is attached to shank 109′ which is pinned to the handle 108 by pin 107. The rod 104′, however, unlike rod 104 of the F key of FIG. 8, is positioned spaced from the bottom of the fingers 106′ to create a hollow region 135. This hollow region provides room to receive the post 123 in FIG. 7a of the lock 52′. The F key does not have this hollow region 135.
Reference is made to FIGS. 24-26 which are respectively similar to FIGS. 20-22 with respect to showing the successive stages of unlocking the latch.
Thus there has been shown a utility meter clamping ring that automatically locks when the locking blade at one end of the ring is inserted into the mating slot of the lock attached to the other end of the split ring. In one embodiment a key can open the lock and in another embodiment, the ring or lock need to be destroyed in order to open the ring.
Locks are disclosed which may be used with different key types such as F or G keys used with commercially available plunger locks.
It will occur to one of ordinary skill that various modifications may be made to the disclosed embodiments. For example, the latch bore 84, FIGS. 5 and 7, and the guide bores 72, 74 and 76, FIG. 5, may be optional and omitted in a further embodiment as shown in FIGS. 12-18. In this embodiment, it is desired that the latch not be capable of being opened and permanently locked as may be desired by some utility companies. In this case, the ring assembly needs to be permanently destroyed to open the meter cover as described. Thus no key is required for this clamping ring embodiment. An installation of a new replacement clamping ring assembly is required if the meter needs to be opened. It is intended that the scope of the invention be defined by the appended claims.
Patent Application
20060277955
