APPARATUS AND METHOD FOR SELF-ADJUSTING, RANGE FINDING AIM POINT FOR RIFLE MOUNTING OPTICS

[0001] The present invention relates to apparatus and method for finding aim for a firearm, and more particularly, to self-adjusting rifle-mounted optics.

[0002] Modern war fighters, i.e., soldiers, snipers, marksman use many different types of rifle-mounted optics to more effectively aim and engage a target while compensating for bullet drop, or the pull of gravity exerted on a bullet in flight that causes the bullet to drop to the ground. Current solutions require a user to compensate for bullet drop by manually lifting the barrel at his/her own discretion to ensure that the round reaches and strikes the target at the desire location.

[0003] Currently, there are numerous rifle-mounted optics that attempt to compensate for bullet drop. Some optics provide reticles that are formed by physical tic marks on the internal optics of the sight, and that allow the user to estimate the effect of bullet drop at an estimated distance. Examples of these can be seen in scout/sniper optics, scopes or telescopic sights. However, the tic marks are oftentimes based off of physical characteristics of the target (i.e. shoulder width) that may drastically vary from target to target or from the user's point of view. Other common war fighter optics, red-dot sights and popular electro-optic sights utilize a see-through lens with a simple red-dot reticle that a user zeroes in on a target. These sights do not provide tics or any other form of adjustment other than intuition on the user's behalf. Again the user estimates the distance to the target, i.e., “range distance” and also the effect of bullet drop at that range distance.

[0004] Laser range finders are a common tool utilized by soldiers, snipers, marksman and relate to many aspects of the duties of the war fighter. To date there has been no combination of a range finder and a rifle-mounted optic that provides range finding ability with automated bullet drop compensation.

[0005] Wherefore, it is an object of the present invention to overcome the above mentioned shortcomings and drawbacks associated with the prior art.

[0006] A further object of the present invention is to provide rifle-mounted optics having a range finding capability to detect the distance to the target and automatically adjust the reticle to compensate for the bullet-drop.

[0007] Yet another object of the present invention is to enable automated calculation of estimated bullet drop and the real-time visual projection of an adjusted reticle onto the display of the optic, thereby enhancing the accuracy and efficiency of shooting by quick and accurate range-to-target identification, reticle adjustment and shot placement assistance. By providing the technology to calculate for bullet drop and an auto adjusting reticle on the optic, the user only has to focus on placing the fixed reticle on the center-mass of the target. This is a significant advantage to war fighters and increases the chances that soldiers may more safely and effectively engaged enemies.

[0008] A further object of the present invention is to enable any soldier equipped with this self-adjusting rifle-mounted optic system to call in close air support (CAS) and indirect fire (including mortars and artillery) quicker and with greater accuracy than the current need for manual estimation, decreasing the need for additional weight bearing equipment designed and currently utilized to provide this ability.

[0009] The present invention relates to a method for finding aim for a rifle comprising the steps of: acquiring a range to a target; calculating an estimated bullet drop based on the range to the target; adjusting a reticle to compensate for the estimated bullet drop; and displaying the adjusted reticle on the optic to allow for an accurate shot.

[0010] The present invention also relates to a self-adjusting optic system for mounting on a firearm that comprises a range finder for acquiring a range to a target. A processor which calculates an estimated bullet drop based on the acquired range to the target. A reticle which is adjustable so as to compensate for the estimated bullet drop based on the acquired range to the target. An optic having a display device on which the adjustable reticle is displayed to facilitate an accurate shot with the firearm.

[0011] The present invention also relates to method for finding aim for a firearm comprising steps of: initially aiming the firearm to align a fixed reticle in an optical scope of the firearm with a desired point of impact of a bullet on the target; actuating a range finder with a pressure switch to acquire a range to the target; transmitting the acquired range to the target to a processor; calculating, with the processor, a bullet drop based on the acquired range to the target; determining, with the processor, a position on a display device at which an adjusted reticle is to be displayed in the optical scope based on the calculated bullet drop; displaying the adjusted reticle on the display device in the optical scope in the determined position, the adjusted reticle defining an actual point of impact of the bullet on the target; and realigning the firearm such that the adjusted reticle is aligned with the desired point of impact of the bullet on the target.

[0023] It should be understood that the drawings are not necessarily to scale and that the disclosed embodiments are sometimes illustrated diagrammatical and in partial views. In certain instances, details which are not necessary for an understanding of this disclosure or which render other details difficult to perceive may have been omitted. It should be understood, of course, that this disclosure is not limited to the particular embodiments illustrated herein.

[0024] The present invention will be understood by reference to the following detailed description, which should be read in conjunction with the appended drawings. It is to be appreciated that the following detailed description of various embodiments is by way of example only and is not meant to limit, in any way, the scope of the present invention.

[0025] Turning now to FIGS. 1-3, a brief description concerning the various components of the present invention will now be briefly discussed. As can be seen, FIG. 1 depicts a firearm 2 including a trigger 4 which can be actuated by a user to fire a bullet through a barrel 6 and along a trajectory towards a target. A magazine 8 holds a number of cartridges such that when a bullet is discharged from the cartridge located in the firing chamber 10 at the end of the barrel 6, the now empty cartridge is ejected from the firing chamber 10 and a new cartridge is transferred from the magazine 8 and loaded into the firing chamber 10. Cartridges hold the bullet and enclose an amount of propellant, also called load which is ignited to shoot the bullet from the firearm 2. A sight 12 is mounted to the firearm 2 and comprises a self-adjusting range finding optic system 13 having a sight housing 14, an optical scope 16, a range finder 18, a display screen 20, a processor 22, a memory unit 24, a power switch 26, a source of electrical power 28, a user input device 30, an electronic port 32, and variety of different sensors and instrumentation, which will be described in more detail below.

[0026] The sight housing 14 is generally mounted at the top of the firearm 2 in the illustrated manner such that the line of sight 34 through the optical scope 16 (illustrated as a dashed line) and the axis of the barrel 36 (illustrated as a solid line) are at least substantially parallel. The sight housing 14 according to the current invention houses the elements of the self-adjusting range finding optic system 13 including the optical scope 16, processor 22, the display screen 20 and the electronic port 32. The range finder 18, power switch 26, power source 28, user input device 30 as well as the variety of different sensors and instrumentation can either be housed within or integrated on the sight housing 14. It is however possible that one or more of these elements can be independent of the'self-adjusting range finding optic system 13 and connected to thereto through the sight housing 14 by means of an input connection 38 which accepts simple communication, for example a USB connection.

[0027] An electrical power source 28 can be either located within the sight housing 14 and connected, via electrical leads, to the elements arranged within the sight housing 14 or can be located outside the sight housing 14 and connected to the self-adjusting range finding optic system 13 by means of a power cable that can be received by a power port 42. The power source 28 is formed by one or more removable batteries, the number and electrical power of which is generally based upon the configuration of the self-adjusting range finding optic system 13, It is to be appreciated that the power source 28 can comprise a permanently enclosed battery that can be recharged via the power port 42.

[0028] The supply of electrical power to the self-adjusting range finding optic system 13 can be controlled by a power switch 26 such as a pressure switch 26′. As switches 26, 26′ for selectively connecting a power source 28 to an electrical consumer are generally well known, the electrical connections between the electrical power source 28 and the self-adjusting range finding optic system 13 will not be discussed in further detail here. In one variation of the self-adjusting range finding optic system 13, the power switch 26 is arranged on the sight housing 14. In another variation, the power switch 26′ is arranged at a location remote from the sight housing 14. It is beneficial to position the power switch 26 at a location that does not necessitate the user from diverting his/her view from the target so as to activate the switch 26′ for example at a position adjacent the trigger guard 25. In either case the electrical power switch 26, 26′ connects the power source 28 to the elements of the self-adjusting range finding optic system 13. In another variation, a pair power switches 26, 26′ can be connected to the self-adjusting range finding optic system 13. In this case, the self-adjusting range finding optic system 13 can have a first power switch located 26 located on the sight housing 14 which is utilized to initially “power up” the self-adjusting range finding optic system 13. The second power switch 26′ is formed as a pressure switch which communicates with the self-adjusting range finding optic system 13 by way of a communication line 5. The pressure switch 26′ is utilized to “wake up” the self-adjusting range finding optic system 13 from a “sleep mode.” A sleep mode of type of operation is utilized in a manner to conserve electrical energy when the self-adjusting range finding optic system 13 is not actively functioning. The pressure switch 26′ can be arranged near the trigger 4 within reach of the trigger finger on the firearm 2 so as to “wake up” the self-adjusting range finding optic system 13 at a time when the user is preparing to engage a target 48. In this case, the pressure switch 26′ is located adjacent the trigger guard 25 such that when the user lifts and initially aims the firearm 2 in preparation for engaging the target 48, the user is able to press the pressure switch 26′ with his/her trigger finger to activate the self-adjusting range finding optic system 13 without significant movement of the hand from it's current position. The pressure switch 26′ can communicate with signaling unit 44 such when the pressure switch 26′ is actuated, the signaling unit 44 issues an indicator signal to notify the user, for example, by means of a visual, audible or tactile signal that the self-adjusting range finding optic system 13 has been powered on. That is to say, when the pressure switch 26′ is actuated, a light can be illuminated or a beep or click can be produced.

[0029] The sight 12 can be implemented using a layout that is common to many current war fighters and can include a telescopic sight such as scout/sniper sight which provides a fixed power magnification level, e.g., 3× magnification. The self-adjusting range finding optic system 13 can include a multifunction laser/illumination device, which can be connected to or rather integrated within the telescopic sight for enhancing precise aiming of the firearm 2, target acquisition and illumination of a target and/or specific area. The multifunction laser device can include a red light laser and/or an IR laser. A red light laser is visible and can therefore assist the user with aiming the firearm when sighting the target with the naked eye. To sight the target in this manner, the user turns on the red laser light and points the firearm at the target. When viewed through the sight, the user is able to clearly see and align a red laser dot at the target. If properly calibrated for distance to the target, the red laser dot viewed on the target signifies the point of impact. One drawback of the red light laser is that it is visible by the target, thus providing the target with a warning of the impending shot. As the red light laser is visible, the position of the user may also easily be detected and therefore compromised. The IR laser on the other hand emits infra-red laser light which is generally not visible. The IR laser can be used in combination with a night-vision system which enables the infra-red light to be seen by the user. The IR laser/night-vision system together make it possible to illuminate targets in low light conditions without the target detecting visible light. Such a multifunction laser device can be integrated with the telescopic sight within the sight housing 14 or can be remote from the telescopic sight. If a remote multifunction laser device is utilized with the self-adjusting range finding optic system 13, the laser device will include an output cable or the like that is able to be connected to the telescopic sight by way of the input connection 38. The multifunction laser/illumination device further includes a floodlight which can be used in dark or rather low-light situations to assist in identifying targets.

[0030] An important aspect of the self-adjusting range finding optic system 13 is the range finder 18. As indicated above the range finder 18 can be arranged within or remote from the sight housing 14, but in either case the range finder 18 is connected to or integral with the processor 22. It is to be appreciated that the range finder 18 can also comprise the processor 22. If the range finder 18 is remote from the sight housing 14, the range finder 18 will communicate with the processor 22 by way of the input connection 38. The range finder 18 can be a laser range finder which is utilized in conjunction with the multifunction laser device described above or the range finder 18 can be used instead the multifunction laser device. In the case that the range finder is utilized in conjunction with the multifunction laser device, the processor 22 communicates with and coordinates the function of both, such that the multifunction laser device will be controlled so as to emit coded-laser pulses 46, while the range finder 18 is controlled by the processor 22 to detect the reflected laser light pulses 46′ and start and stop a timer 48 as discussed below in further detail. If the multifunction laser device is however not used in combination with the range finder 18, the range finder 18 will perform both of these functions. In general, the laser range finder 18 can be actuated by the pressure switch 26′ when the user initially aims the firearm 2 at the target 48.

[0031] When actuated the laser range finder 18 directs focused coded pulses of laser light 46 at the target 48 and simultaneously starts a connected timer 48. Upon striking the target 48, the pulses of laser light 46 reflect off the target 48 and are directed back toward the user. That is to say, when the pulses of laser light hit 46 the target 48, a portion of the laser light is reflected back to the laser range finder 18 mounted on the firearm 2. The laser range finder 18 has a light sensor 50 which detects the reflected pulses of laser light 46′. Upon detecting the reflected laser light 46′, the laser range finder 18 stops the timer 48 and records the amount of time that has lapsed from the time the pulses of laser light 46 were emitted by the laser range finder 18 to the time the reflected pulses of laser light 46′ were detected by the light sensor 50. As the speed at which light travels is known, the laser range finder 18 can calculate the distance to the target 48 based on the amount of time that had lapsed from the time the pulses of laser light 46 were emitted by the laser range finder. 18 to the time reflected pulses of laser light 46′ were detected by the light sensor 50. The distance from the range finder 16, i.e. the user, to the target 48 is hereinafter referred to as the “range distance”.

[0032] It is to be appreciated that the range finder 18 can determine the range distance at a time selected by the user by actuating the pressure switch 26, 26′, or at certain intervals of time (for example, every second) or the range distance can be determined continuously. In the case that the range distance is continuously determined, the range distance will automatically change as the user aims the firearm at different targets.

[0033] The inventive self-adjusting range finding optic system 13 utilizes an optical scope 16 having a fixed reticle 52 and a display screen 20 which is able to display a variable reticle 54. The position at which the variable reticle 54 is displayed on the display screen 20 is controlled by the processor 22, such that the position of the variable reticle 54 in the view field of the optical scope can be adjusted automatically depending on determined range distance range distances and, optionally, based on a number of other factors to be discussed below.

[0034] The display screen 20 enables the user to view the variable reticle 54 in the optical scope 16 in addition to various other data and information that may be relevant to precise aiming of the firearm 2 on the target 48. In one variation of the self-adjusting range finding optic system 13, a “honeycomb” attachment of a telescopic sight or scope could be used as a display screen 20 on which the variable reticle 54 as well as other data and information, e.g., distance, direction and/or location are projected. Such a display screen 20 enables the user to view the variable reticle 54 and pertinent other data and information while at the same time maintaining a view of the target 48. Another variation of the self-adjusting range finding optic system 13 may utilize an electro-optical sight having a 3× attachment as the sight 12 which allows the user to look through the optical scope 16 and adjust the aim of the firearm 2 based on the position of the variable reticle 54 in the view field of the optical scope 16. A further variation may combine an electro-optical sight with a small prism which are used in combination to reflect the variable reticle 54, data and information from a base onto the display screen 20. In yet a further variation of the self-adjusting range finding optic system 13, digital optics may be used to digitally project a variable reticle 54 in the sight picture.

[0035] In any case a fixed reticle 52, which may include a vertical crosshair 56 and horizontally aligned tick marks 58, is permanently imprinted on or etched in the optics of the optical scope 16. The variable reticle 54 on the other hand is projected as a red dot onto the display screen 20 and can be automatically adjusted in the manner described below so as to compensate for bullet drop based on the determined range distance as well as other factors that are known to cause changes in the trajectory 60 of a bullet. Although the figures illustrate the variable reticle 54 as a solid colored dot, it is to be appreciated that the variable reticle 54 can be displayed in any other form and color, for example crosshairs or an arrow head. The important aspect of the variable reticle 54 is that it be distinctly visible within the view field.

[0036] Before describing the process of automatically adjusting the variable reticle 54, a number of other factors will be discussed that can impact the trajectory 60 of a bullet and therefore negatively impact aiming of the firearm 2 based on the range distance. Such factors can include ballistic information, environmental information and geographic information. In addition to these factors, it is further possible to project system status information onto the display screen 20 such as the remaining supply of power in the power source 28 or the location coordinates of the target 48.

[0037] As briefly noted above, ballistic information can be taken into consideration when adjusting the variable reticle 54 in relation to the target 48 or rather aiming the firearm 2 on the target 48. Ballistic information can include the size, shape, weight and grain of a bullet, the muzzle velocity, and perhaps characteristics of the barrel 6. According to the invention such ballistic information can be input into the processor 22 of the self-adjusting range finding optic system 13 by a user input device 30. The user input device 30 can include a keyboard, a number pad, and/or a touchpad and can facilitate communicating such information to the processor 22 as well as the other components of the self-adjusting range finding optic system 13. An external user input device can communicate with the processor 22 by the input connection 38 located in the sight housing 14. In another variant as shown in FIG. 2, the user input device 30 is integrated into the sight housing 14 and comprises a series of buttons 62 which are pressed in correlation to the image shown on an interface screen 64, such as an LCD that is located on the exterior of the sight housing 14.

[0038] The self-adjusting range finding optic system 13 can further include environmental instrumentation 66 such as sensors that respectively detect environmental and geographic information which might further alter the trajectory of a bullet. Such instrumentation 66 can communicate with the processor 22 and can include a barometer for measuring barometric pressure, a thermometer for measuring atmospheric temperature, a hygrometer for measuring the amount of humidity in the atmosphere, a wind vane and anemometer for measuring wind direction and speed, and an altimeter which can detect the altitude or rather the distance above sea level. External instrumentation (not shown) can transmit associated readings, data and information to the processor 22 via the input connection 38 or they may be integrally associated within the sight housing 14 of the self-adjusting range finding optic system 13.

[0039] The self-adjusting range finding optic system 13 can also have geographical instrumentation 68 such as an inclinometer which determines the incline/decline of the firearm 2 with respect to horizontal. As is known, shooting at a target 48 that is located at an incline or a decline from horizontal with respect to the shooter can alter the range distance. It is therefore desirable that an inclinometer be used in conjunction with the laser range finder 18 so as to more accurately calculate the range distance. When detected by the inclinometer, the angle of incline/decline with respect to horizontal is transmitted to the processor 22 and utilized in the range distance calculation. The geographical instrumentation 68 may also include a GPS and/or digital compass which can provide the self-adjusting range finding optic system 13 with geographic information such as location coordinates and direction orientation that can be relayed by the user when calling in close air support or indirect fire such as mortars and artillery.

[0040] The method of using the self-adjusting range finding optic system 13 will now be described with reference to FIGS. 4-6A. FIGS. 4A, 5A, and 6A depict a series of point-of-view diagrams (according to one embodiment) from the user's perspective looking down the optical scope 16. Although FIGS. 4A, 5A, and 6A illustrate this embodiment as being implemented on scout/sniper type sight comprising the fixed reticle 52 as described above, it is to be appreciated that the self-adjusting range finding optic system 13 may be implemented for example on any other common war fighter optics, red-dot sights or an electro-optical sight.

[0041] In the following description of the method of adjusting a range finding optic system 13, it is to be understood that the axis of the barrel 36 and the line of sight 34 through the optical scope 16 always extend from the firearm 2 parallel with respect to each other. Further the fixed reticle 52 is permanently set in position in the view field of the optical scope 16. That is to say the fixed reticle 52 does not move in relation to the line of sight 34 through the optical scope 16 and is therefore also fixed in position with respect to the axis of the barrel 36 of the firearm 2.

[0042] To initiate the method, the user raises the firearm 2 and looks through the optical scope 16 so as to identify the target 48 and adjust the firearm 2 such that the vertical crosshair 56 and horizontal tick marks 58 of the fixed reticle 52 are approximately centered horizontally on the target 48 as seen in FIG. 4A. The user in addition aims the fixed reticle 52 at the target 48 such that the fixed reticle 52 is generally aligned with a desired point of impact 63 on the target 48 in accordance to what the user was trained to zero in on so as to eliminate the target 48. The desired point of impact 63 on the target 48 is identified in the FIGS. 4-5A by means of an open dot. It is also to be appreciated that the user may view the target 48 through an optic with target identification. Although FIG. 4A indicates that the laser range finder 18 has not been yet been activated, as the variable reticle 54 is not shown in the view field of the optical scope 16, it is to be understood that the laser range finder 18 may alternatively be activated prior to the initial identification of the target 48 and alignment of the fixed reticle 52 on the target 48. The variable reticle 54 first appears in the view field the optical scope 16 when the self-adjusting range finding optic system 13 is actuated and the range distance is determined.

[0043] The user then “wakes up” or rather activates the laser range finder 18 by actuating the pressure switch 26 in STEP 1. As described above in more detail, upon being activated, the laser range finder 18 emits focused, coded pulses of laser light 46 at the target 48 which then strike the target 48 and reflect back toward the laser range finder 18. The reflected pulses of laser light 46′ are then detected by the light sensor 50 of the laser range finder 18 at which point, in STEP 2, the laser range finder 18 determines the distance to the target 48, i.e., range distance based on the amount of time that it takes for the pulses of laser light 46 to travel to and return from the target 48. The laser range finder 18 transmits the determined range distance to the processor 22 in STEP 3.

[0044] Depending at least on the determined range distance and the alignment of the fixed reticle 52 in relation to the target 48, the processor 22 determines the appropriate location at which the variable reticle 54 is projected and set into position on the display screen 20 of the optical scope 16. Once the variable reticle 54 is set in position with respect to the fixed reticle 52, the variable reticle 54 and the fixed reticle 52 remain fixed in this arrangement until the bullet is shot, the user reactivates the laser range finder 18, or it is detected that the range distance has changed. When activated, the variable reticle 54 is recognized as being the same as the actual point of impact of the bullet on the target 48 in STEP 4 and is illustrated in 5-6 as being a lack dot. FIGS. 5 and 6 show the trajectory 60 of the bullet based on the determined range distance. As illustrated, the trajectory 60 of the bullet drops due to the pull of gravity as well as other factors generally described herein. As shown in FIG. 5A, with the fixed reticle 52 being aligned on the target 48 in the manner described above in relation to FIG. 5, if the user were to take this shot without adjustment or realignment of the firearm 2 so as to compensate for bullet drop, the target 48 would have a higher chance of survival than a shot to center mass, thus leaving the user susceptible to the threat. In other words, if the bullet were shot while the firearm 2 was aligned using only the fixed reticle 52, the actual point of impact of the bullet would not match the desired point of impact 63 of the bullet. The actual point of impact shown in FIGS. 5 and 5A and identified by the variable reticle 54 is significantly lower than the desired point of impact 63 as identified by the fixed reticle 52. As stated above the trajectory 60 of a bullet can be impacted by a number of factors such as ballistic information, environmental information and geographic information for example. For this reason, the processor 22 communicates with the associated sensors and/or instruments and receives signals therefrom and subsequently considers these signals when determining the distance to the target 48. To effectively utilize these factors when determining the range distance, the processor 22 is connected to a memory unit 24 which for example can store characteristic tables. It should be appreciated that the term “memory unit” herein is intended to include various types of suitable data storage media, whether permanent or temporary, such as transitory electronic memories, non-transitory computer-readable medium and/or computer-writable medium, With the variety of data and information that can be detected by the associated sensors and instrumentation, the processor 22 can access and utilize the characteristic tables so as to increase the accuracy of setting the position of the variable reticle 54 based on the detected range distance. As an example, one characteristic table can relate to the effect that the shape of the bullet has on the bullet trajectory or another characteristic table can relate to the effect that bullet weight has on the bullet trajectory. Thus with the ballistics information input by the user, the processor 22 accesses these ballistic characteristic tables to determine the measures by which bullet shape and/or weight alters the trajectory of the bullet over the detected range distance. The processor 22 then factors in the information gathered from the characteristic tables and the determined range distance when controlling the location at which the variable reticle 54 is projected and set on the display screen 20 of the optical scope 16.

[0045] Once the position of the variable reticle 54 is set in the view field in relation to the fixed reticle 52, as in FIG. 5A, the user then realigns the aim of the firearm 2 so as to compensate for the amount of bullet drop over the determined range distance. The user realigns the firearm 2 until the actual point of impact 54 matches the desired point of impact 63 as shown in FIGS. 6 and 6A. In the illustrated example, the user lifts the end of the barrel 6 so as to raise the axis 36 of the barrel 6 and line of sight 34 through the optical scope 16. As the variable reticle 54 is now set in position with respect to the fixed reticle 52, both the fixed and variable reticles 52, 54 are also raised in relation to the target 48 when the user raises the view field. In FIGS. 6 and 6A, the firearm 2 and the view field have been lifted such that the actual point of impact, as demarcated by the adjustable reticle 54, is aligned with the desired point of impact 63 on the target 48. In short, the user realigns his/her sight picture to utilize the variable reticle 54 when taking aim and engaging the target 48 in STEP 5.

[0046] While many varieties and/or embodiments of the present invention have been described in detail, it is apparent that various modifications and alterations of those embodiments will occur to and be readily apparent to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the appended claims. Further, the self-adjusting range finding optic system described herein is capable of other embodiments and of being practiced or of being carried out in various other related ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items while only the terms “consisting of” and “consisting only of” are to be construed in a limitative sense.