The Laser Rock Measure (LRM) was developed to provide a quick and simple method of determining how far a rock is from the pin. Only one official is needed to make the measurements.

The LRM employs laser distance measuring technology to determine the distance a rock is from the dead-centre of the pin. The laser itself is set back 0.15m (15 cm) from the dead-centre of the pin which permits the device to accurately measure rocks that are biting the pin. This set back (0.15m) should be subtracted from readings on the laser if the rock’s actual distance from the dead-centre of the pin is desired.

The LRM has been designed to maintain the laser beam parallel to the ice surface when it is resting flat on the ice surface. This is important so the laser beam will strike the same height on a rock’s hitting band no matter how near or distant it is from the pin.

Since there is no need to physically touch the measured rock, there is no danger the rock will be moved during the measurement.

Although the LRM was originally developed specifically for “draw to the button” for first end hammer or to resolve tied games, it can also be used as a general measuring device in determining shot rock during play of a game.

Although the LRM has some limitations when measuring multiple rocks that closely surround the button, we have developed the LRM Mirror Accessory (LMA) described below, which alleviates this limitation and makes the LRM capable of determining shot rock in virtually all scenarios requiring a measure.

LRM Storage Box (LSB)

The LRM Storage Box (LSB) is a clear plastic box with a hinged lid that can be used to store the LRM in the curling club ice shed. It can be mounted on a shelf using the included double sided tape or with two #6 screws (not included) through the pre-drilled holes in the base. When installing the screws, be careful not to overtighten and crack the plastic case.

The LRM Plus

The LRM Plus has essentially the same configuration as the original LRM but incorporates a newer Bosch laser measure, the GLM 50C. The GLM 50C provides enhanced functionally and accuracy compared to the laser measure used in the original LRM. It has a resolution of +/- 0.5 mm compared to +/- 1.0 mm for the older Bosch laser measures, a backlit display and Bluetooth capability.

Since the laser measures the distance from the back of the laser measure to the target, actual readings shown on the LRM Plus are 15 cm greater than the actual distance. This is only significant when an absolute distance from the rock to the pin is required. For relative measurements (i.e. which rock is closer to the pin), it is only necessary to note the difference between the readings for each rock; the rock with the lowest reading is shot rock.

The following describes the significant features that the LRM Plus provides:

1. Sweep and hold measurement of a rock's distance from the Pin or Tee. Using the LRM Plus a user merely has to slowly sweep the laser beam across the hitting-band of the rock being measured and the top line of the display shows and holds the shortest distance between the Pin and the rock
2. With resolution of +/- 0.5 mm, compared to +/- 1.0 mm for the older Bosch laser measures, it is less likely to have a tie when determining shot rock.
3. The back lit display provides better visibility especially in poor lighting conditions.
4. The LRM Plus has Blue Tooth capability which facilitates the remote display of the GLM 50c readings on a tablet or mobile phone possible. This feature will be useful for future applications to save data and display readings on scoreboards and TV monitors.

The functionally described above allows the LRM Plus to be used to determine shot during play rather than a micrometer measuring stick. For measurements inside the four-foot circle measuring sticks lack lateral support, compromising their accuracy. This is not a problem for the LRM family of measuring devices. Using the LRM Plus in conjunction with the Laser Mirror Accessory (LMA), described separately, covers virtually all rock position scenarios encountered during play.

LRM with Backlit Display (LRM BL)

We introduced the LRM with a backlit display (LRM BL) in December 2018. This version costs a bit more but is easier to read in low light conditions. It is otherwise functionally equivalent to the basic LRM. Now that the non-backlit versions of the Bosch display are no longer available, the LRM BL has replaced the LRM in our inventory.

The LRM Mirror Accessory (LMA)

The LMA has been designed to enable measurements with the LRM in cases where the LRM alone cannot make a measurement. The upper portion of the LMA (the reflector) has a mirror embedded in a rotatable knob to redirect the laser beam. This enables measurements to be made in tight quarters where the LRM cannot be maneuvered due to rock placement.

Instructions for using the LRM Mirror Accessory (LMA)

Follow the “Initial Set-up” instructions in the Operating Manual for the Laser Rock Measure. Make sure the nut is tightened on the set screw.

Screw the LMA onto the set screw. Make sure it is screwed all the way down so it is snug on the base.

When the LMA is installed, all measurements must be done by adjusting the mirror so the laser beam strikes the target rock's hitting band.

Follow the “Making Measurements” instructions in the Operating Manual for the Laser Rock Measure. Note that either the LRM or the mirror may be rotated to “direct the beam at rock to be measured” and “adjust for closest measurement”.

Caution

The mirror used in the LMA is a special type of “first Surface Mirror”, meaning the reflecting surface is the face of the mirror rather than the back surface as in conventional mirrors. This is required to prevent multiple reflections that would reduce accuracy of the LRM.

Care should be taken to avoid scratching the mirror. If cleaning is required, use only a soft lint-free cloth and mild cleaning solution such as camera lens cleaner or eye glass cleaner. Never use abrasive materials to clean the mirror's surface.

Product Evolution 

The Auto-adjust pin, described on the “ What's New” page, represents a significant upgrade to the capabilities of the LRM. However, due to the higher cost of this precision machined assembly, we have decided to upgrade only the LRM Plus at this time. All new orders for the LRM Plus will include the Auto-adjust pin.

We will offer the Auto-adjust pin as a factory installed option on the backlit LRM and as a retro-fit kit for units in the field. Modification of LRMs in the field is not offered due to the requirement for machining of the base to accommodate the Auto-adjust pin installation.

The Auto-Adjust Pin Base (AAPB) retro fit kit includes a new LRM base with the auto-adjust pin installed. Assembly involves removing the existing base (2 screws) and installing the Auto-adjust pin assembly.